IUCN Red List Assessment Drafts — 36 Canarian Endemic Spider Species

IUCN Guidelines v16 (March 2024) · Categories v3.1 · Threats Classification v3.3 (Dec 2022)

Overview

Draft IUCN Red List assessments for 36 endemic spider species of the Canary Islands (Spain), prepared following the most current IUCN standards:

• Categories & Criteria: Version 3.1 (IUCN 2001, 2012)
• Guidelines: Version 16, March 2024
• Threats Classification Scheme: Version 3.3, December 2022
• Supporting Information: “Required and Recommended Supporting Information for IUCN Red List Assessments” (SSC 2016, Annex 1 to the Rules of Procedure)

CR (Critically Endangered): 19 speciesEN (Endangered): 13 speciesDD (Data Deficient): 4 species

Summary table

Species	Family	Cat.	Criteria	EOO (km²)	AOO (km²)	Loc.	Islands	Rec.	Georef
Canarionesticus quadridentatus	Nesticidae	CR	B1a(i)b(iii); D2	82.5	16	3	Tenerife	6	6
Dysdera gibbifera	Dysderidae	CR	B1a(i)b(iii); D2	72.4	20	4	Tenerife	35	34
Dysdera gollumi	Dysderidae	CR	B1a(i)b(iii); B2a(i)b(iii); D2	8.0	8	2	Tenerife	14	13
Dysdera hernandezi	Dysderidae	CR	B1a(i)b(iii); B2a(i)b(iii); D2	8.0	8	2	Tenerife	10	10
Dysdera labradaensis	Dysderidae	CR	B1a(i)b(iii); D2	89.2	16	3	Tenerife	25	24
Dysdera sibyllina	Dysderidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	8.0	8	1	Tenerife	10	10
Dysdera unguimmanis	Dysderidae	CR	B1a(i)b(iii); D2	12.0	12	2	Tenerife	37	32
Dysdera volcania	Dysderidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	8.0	8	1	Tenerife	7	7
Lepthyphantes palmeroensis	Linyphiidae	CR	B1a(i)b(iii); B2a(i)b(iii); D2	8.0	8	2	La Palma	3	3
Metopobactrus cavernicola	Linyphiidae	CR	B1a(i)b(iii); B2a(i)b(iii); D2	8.0	8	2	Tenerife	7	7
Ossinissa justoi	Pholcidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	El Hierro	6	6
Pholcus baldiosensis	Pholcidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	Tenerife	3	1
Spermophorides anophthalma	Pholcidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	La Palma	4	4
Spermophorides fuertecavensis	Pholcidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	Fuerteventura	2	2
Spermophorides reventoni	Pholcidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	Tenerife	5	5
Troglohyphantes labrada	Linyphiidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	Tenerife	1	1
Troglohyphantes roquensis	Linyphiidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	Gran Canaria	2	2
Walckenaeria cavernicola	Linyphiidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	Tenerife	1	1
Zimirina grancanariensis	Prodidomidae	CR	B1a(ii)b(iii); B2a(ii)b(iii); D2	4.0	4	1	Gran Canaria	1	1
Agraecina canariensis	Liocranidae	EN	B1a(i)b(iii); B2a(i)b(iii); D2	3539.0	24	5	Gran Canaria, Tenerife	57	53
Dysdera ambulotenta	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii); D2	240.5	24	5	Tenerife	31	30
Dysdera breviseta	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii)	445.4	64	6	Tenerife	221	218
Dysdera brevispina	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii)	3798.5	80	13	Gran Canaria, Tenerife	148	130
Dysdera chioensis	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii)	228.6	24	6	Tenerife	28	28
Dysdera cribellata	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii)	843.8	68	11	Tenerife	326	264
Dysdera curviseta	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii); D2	205.5	12	3	Tenerife	17	17
Dysdera esquiveli	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii); D2	307.2	20	5	Tenerife	48	44
Dysdera guayota	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii)	918.5	40	10	La Gomera, Tenerife	63	50
Dysdera iguanensis	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii)	3208.1	60	9	Gran Canaria, Tenerife	187	178
Dysdera madai	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii)	483.9	28	6	Tenerife	59	59
Dysdera ratonensis	Dysderidae	EN	B1a(i)b(iii); B2a(i)b(iii)	328.2	40	10	La Palma	43	43
Troglohyphantes oromii	Linyphiidae	EN	B1a(i)b(iii); B2a(i)b(iii)	301.0	28	7	Tenerife	50	38
Centromerus fuerteventurensis	Linyphiidae	DD	Data Deficient — no records in databases	0.0	0	0		0	0
Lepthyphantes styx	Linyphiidae	DD	Data Deficient — no records in databases	0.0	0	0		0	0
Spermophorides flava	Pholcidae	DD	Data Deficient — 1 records, none georeferenced	0.0	0	0	Gran Canaria	1	0
Walckenaeria subterranea	Linyphiidae	DD	Data Deficient — no records in databases	0.0	0	0		0	0

Compliance with IUCN Required Supporting Information (2016)

Each species account includes all fields required by Annex 1 of the Rules of Procedure (2017-2020):

RSI requirement (Table 1 of the PDF)	Location in this document
1. Scientific name	“Taxonomy” header
2. Higher taxonomy (Kingdom–Family)	“Taxonomy” section
3. Taxonomic authority	“Taxonomy” section
4. IUCN Category & Criteria (with sub-criteria)	“Red List status” section
5. Rationale for the assessment	“Assessment rationale” section
6. Data for parameters triggering the criteria (EOO, AOO, n locations, severely fragmented)	“Geographic range” and “Population” sections
7. Countries of occurrence, with Presence/Origin coding	“Countries of occurrence” table
8. Geo-referenced distribution data	Interactive map + linked GIS shapefile / CSV
9. Direction of current population trend	“Population” section
10. System coding (terrestrial / freshwater / marine)	“Habitat and ecology” section
11. Suitable habitats (coded to lowest level of Habitats Classification)	“Habitat and ecology” table
12. Bibliography (in full)	“Bibliography” section
13. Assessor(s) and Reviewer(s)	“Assessment information” section
Under specific conditions (Table 2):
8. Severely-fragmented coding / number of locations (for B1a/B2a)	“Assessment rationale”
14. Major threats, coded to lowest level of Threats Classification v3.3	“Threats” table
15. Narrative text on range, population, habitat, threats	Per-species narrative
Recommended (Table 3):
5. Elevation limits	“Habitat and ecology”
6. Stresses and timing for threats	“Threats” table (Stresses column)
7-8. Conservation actions in place and needed	“Conservation” section

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Canarionesticus quadridentatus — CR

Taxonomy

• Scientific name: Canarionesticus quadridentatus Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Nesticidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(i)b(iii); D2) because the extent of occurrence (EOO) is 82.5 km² (below the CR threshold). It is known from 3 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 16 km², 3 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 82.5 km² (MCP); AOO = 16 km² (2×2 km grid).

Key localities: Felipe Reventón, Cueva de; Labrada, Cueva de La; Perdiz, Sima de la; Sobrado, Cueva del.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 6 records across 4 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Canarionesticus quadridentatus is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Dysdera gibbifera — CR

Taxonomy

• Scientific name: Dysdera gibbifera Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(i)b(iii); D2) because the extent of occurrence (EOO) is 72.4 km² (below the CR threshold). It is known from 4 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 20 km², 4 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 72.4 km² (MCP); AOO = 20 km² (2×2 km grid).

Key localities: Agua, Monte del; Cochinos, Barranco de los; Icod de los Vinos; Ijuana; Ijuana, Hoya de; Los Silos; Santa Cruz de Tenerife.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 35 records across 6 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera gibbifera is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Dysdera gollumi — CR

Taxonomy

• Scientific name: Dysdera gollumi Ribera & Arnedo, 1994
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(i)b(iii); B2a(i)b(iii); D2) because the extent of occurrence (EOO) is 8.0 km² (below the CR threshold) and the area of occupancy (AOO) is 8 km² (below the CR threshold). It is known from 2 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 8 km², 2 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 8.0 km² (MCP); AOO = 8 km² (2×2 km grid).

Key localities: Guía de Isora; La Orotava; Roques, Cueva de Los.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 14 records across 2 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera gollumi is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Dysdera hernandezi — CR

Taxonomy

• Scientific name: Dysdera hernandezi Ribera & Arnedo, 1999
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(i)b(iii); B2a(i)b(iii); D2) because the extent of occurrence (EOO) is 8.0 km² (below the CR threshold) and the area of occupancy (AOO) is 8 km² (below the CR threshold). It is known from 2 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 8 km², 2 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 8.0 km² (MCP); AOO = 8 km² (2×2 km grid).

Key localities: El Sauzal; Labrada, Cueva de La; Santa Cruz de Tenerife.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 10 records across 3 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera hernandezi is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera labradaensis — CR

Taxonomy

• Scientific name: Dysdera labradaensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(i)b(iii); D2) because the extent of occurrence (EOO) is 89.2 km² (below the CR threshold). It is known from 3 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 16 km², 3 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 89.2 km² (MCP); AOO = 16 km² (2×2 km grid).

Key localities: Bucio, Cueva del; El Sauzal; Felipe Reventón, Cueva de; Icod de Los Vinos; Icod de los Vinos; La Orotava; Labrada, Cueva de La; Sobrado, Cueva del.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 25 records across 7 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera labradaensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Dysdera sibyllina — CR

Taxonomy

• Scientific name: Dysdera sibyllina Arnedo, 2007
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 8.0 km² (below the CR threshold) and the area of occupancy (AOO) is 8 km² (below the CR threshold). It is known from 1 location(s) on a single island (Tenerife), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 8 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 8.0 km² (MCP); AOO = 8 km² (2×2 km grid).

Key localities: Icod de Los Vinos; Icod de los Vinos; Ingleses, Galería de los.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 10 records across 4 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera sibyllina is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera unguimmanis — CR

Taxonomy

• Scientific name: Dysdera unguimmanis Ribera, Ferrández & Blasco, 1986
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(i)b(iii); D2) because the extent of occurrence (EOO) is 12.0 km² (below the CR threshold). It is known from 2 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 12 km², 2 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 12.0 km² (MCP); AOO = 12 km² (2×2 km grid).

Key localities: Breveritas, Cueva de; Bucio, Cueva del; Cueva del Viento; Felipe Reventón, Cueva de; Icod de Los Vinos; Icod de los Vinos; Ingleses, Cueva de los; La Orotava; Sobrado, Cueva del; Viento, Cueva del.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 37 records across 7 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera unguimmanis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera volcania — CR

Taxonomy

• Scientific name: Dysdera volcania Ribera, Ferrández & Blasco, 1986
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 8.0 km² (below the CR threshold) and the area of occupancy (AOO) is 8 km² (below the CR threshold). It is known from 1 location(s) on a single island (Tenerife), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 8 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 8.0 km² (MCP); AOO = 8 km² (2×2 km grid).

Key localities: Felipe Reventón, Cueva de; Icod de Los Vinos; Icod de los Vinos.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 7 records across 3 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera volcania is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Lepthyphantes palmeroensis — CR

Taxonomy

• Scientific name: Lepthyphantes palmeroensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(i)b(iii); B2a(i)b(iii); D2) because the extent of occurrence (EOO) is 8.0 km² (below the CR threshold) and the area of occupancy (AOO) is 8 km² (below the CR threshold). It is known from 2 location(s) on a single island (La Palma), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 8 km², 2 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (La Palma). EOO = 8.0 km² (MCP); AOO = 8 km² (2×2 km grid).

Key localities: Diablo, Cueva del; Palmeros, Cueva de los.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (La Palma)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 3 records across 2 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Lepthyphantes palmeroensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional de la Caldera de Taburiente. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Metopobactrus cavernicola — CR

Taxonomy

• Scientific name: Metopobactrus cavernicola Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(i)b(iii); B2a(i)b(iii); D2) because the extent of occurrence (EOO) is 8.0 km² (below the CR threshold) and the area of occupancy (AOO) is 8 km² (below the CR threshold). It is known from 2 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 8 km², 2 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 8.0 km² (MCP); AOO = 8 km² (2×2 km grid).

Key localities: Felipe Reventón, Cueva de; Roques, Cueva de Los.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 7 records across 2 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Metopobactrus cavernicola is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Ossinissa justoi — CR

Taxonomy

• Scientific name: Ossinissa justoi (Wunderlich, 1992)
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Pholcidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (El Hierro), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (El Hierro). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Don Justo, Cueva de.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (El Hierro)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 6 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Ossinissa justoi is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

ZEC areas protect some cave habitats. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Pholcus baldiosensis — CR

Taxonomy

• Scientific name: Pholcus baldiosensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Pholcidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (Tenerife), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Baldíos, Cueva de los; Roques, Cueva de Los.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 3 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Pholcus baldiosensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Spermophorides anophthalma — CR

Taxonomy

• Scientific name: Spermophorides anophthalma Wunderlich, 1999
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Pholcidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (La Palma), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (La Palma). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Palmeros, Cueva de los .

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (La Palma)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 4 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Spermophorides anophthalma is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional de la Caldera de Taburiente. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Spermophorides fuertecavensis — CR

Taxonomy

• Scientific name: Spermophorides fuertecavensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Pholcidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (Fuerteventura), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Fuerteventura). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Llano, Cueva del (Villaverde).

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Fuerteventura)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 2 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Spermophorides fuertecavensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Spermophorides reventoni — CR

Taxonomy

• Scientific name: Spermophorides reventoni Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Pholcidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (Tenerife), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Felipe Reventón, Cueva de.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 5 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Spermophorides reventoni is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Troglohyphantes labrada — CR

Taxonomy

• Scientific name: Troglohyphantes labrada Wunderlich, 2012
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (Tenerife), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Labrada, Cueva de La.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 1 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Troglohyphantes labrada is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Troglohyphantes roquensis — CR

Taxonomy

• Scientific name: Troglohyphantes roquensis Barrientos & Fernández-Pérez, 2018
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (Gran Canaria), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Gran Canaria). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Los Roques, Mina.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Gran Canaria)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 2 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Troglohyphantes roquensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Walckenaeria cavernicola — CR

Taxonomy

• Scientific name: Walckenaeria cavernicola Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (Tenerife), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Roques, Cueva de Los.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 1 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Walckenaeria cavernicola is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Zimirina grancanariensis — CR

Taxonomy

• Scientific name: Zimirina grancanariensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Prodidomidae
• Common names: No widely used common name

Red List status

CR — Critically Endangered

Criteria: B1a(ii)b(iii); B2a(ii)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Critically Endangered (B1a(ii)b(iii); B2a(ii)b(iii); D2) because the extent of occurrence (EOO) is 4.0 km² (below the CR threshold) and the area of occupancy (AOO) is 4 km² (below the CR threshold). It is known from 1 location(s) on a single island (Gran Canaria), the species is known from only 1 location(s) [subcriterion a(ii)], and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 4 km², 1 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Gran Canaria). EOO = 4.0 km² (MCP); AOO = 4 km² (2×2 km grid).

Key localities: Tirajana.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Gran Canaria)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 1 records across 1 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Zimirina grancanariensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Agraecina canariensis — EN

Taxonomy

• Scientific name: Agraecina canariensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Liocranidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii); D2) because the extent of occurrence (EOO) is 3539.0 km² (below the EN threshold) and the area of occupancy (AOO) is 24 km² (below the EN threshold). It is known from 5 location(s) on 2 islands (Gran Canaria, Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 24 km², 5 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from 2 islands (Gran Canaria, Tenerife). EOO = 3539.0 km² (MCP); AOO = 24 km² (2×2 km grid).

Key localities: Arico; Baldíos, Cueva de los; Chío, Cueva Grande de; Chío, Pinar de; Felipe Reventón, Cueva de; Marteles, Caldera de los; Robada, Sima de la; Tirajana; Viento, Cueva del.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Gran Canaria)	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 57 records across 7 unique localities. Populations on 2 islands (Gran Canaria, Tenerife) with no genetic exchange between them. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Agraecina canariensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera ambulotenta — EN

Taxonomy

• Scientific name: Dysdera ambulotenta Ribera, Ferrández & Blasco, 1986
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii); D2) because the extent of occurrence (EOO) is 240.5 km² (below the EN threshold) and the area of occupancy (AOO) is 24 km² (below the EN threshold). It is known from 5 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 24 km², 5 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 240.5 km² (MCP); AOO = 24 km² (2×2 km grid).

Key localities: Bucio, Cueva del; Cueva del Viento; El Sauzal; Felipe Reventón, Cueva de; Icod de Los Vinos; Icod de los Vinos; La Orotava; Labrada, Cueva de La; Roques, Cueva de Los; Sobrado, Cueva del.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 31 records across 12 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera ambulotenta is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera breviseta — EN

Taxonomy

• Scientific name: Dysdera breviseta Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 445.4 km² (below the EN threshold) and the area of occupancy (AOO) is 64 km² (below the EN threshold). It is known from 6 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 445.4 km² (MCP); AOO = 64 km² (2×2 km grid).

Key localities: La Orotava; Los Realejos; Los Silos; San Cristóbal de La Laguna; Santa Cruz de Tenerife; Santiago del Teide; Tegeste; Tegueste.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 221 records across 32 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera breviseta is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera brevispina — EN

Taxonomy

• Scientific name: Dysdera brevispina Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 3798.5 km² (below the EN threshold) and the area of occupancy (AOO) is 80 km² (below the EN threshold). It is known from 13 location(s) on 2 islands (Gran Canaria, Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from 2 islands (Gran Canaria, Tenerife). EOO = 3798.5 km² (MCP); AOO = 80 km² (2×2 km grid).

Key localities: Adeje; Agua, Monte del; Aguirre, Monte; Alto, Teno; Batán-Cruz del Carmen, Pista El; Breveritas, Cueva de; Carmen, Cruz del; Cochinos, Barranco de los; Cueva del Viento; Felipe Reventón, Cueva de.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Gran Canaria)	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 148 records across 31 unique localities. Populations on 2 islands (Gran Canaria, Tenerife) with no genetic exchange between them. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera brevispina is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera chioensis — EN

Taxonomy

• Scientific name: Dysdera chioensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 228.6 km² (below the EN threshold) and the area of occupancy (AOO) is 24 km² (below the EN threshold). It is known from 6 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 228.6 km² (MCP); AOO = 24 km² (2×2 km grid).

Key localities: Chío, Cueva Grande de; Guía de Isora; Güímar; La Orotava.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 28 records across 7 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera chioensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Dysdera cribellata — EN

Taxonomy

• Scientific name: Dysdera cribellata Simon, 1883
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 843.8 km² (below the EN threshold) and the area of occupancy (AOO) is 68 km² (below the EN threshold). It is known from 11 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 843.8 km² (MCP); AOO = 68 km² (2×2 km grid).

Key localities: Agua, Monte del; Aguirre, Monte; Anaga. La Laguna; Arafo; Arafo. Subida al Teide; Batán-Cruz del Carmen, Pista El; Bodegas, Las; Carmen, Cruz del; Chío, Pinar de; Guía de Isora.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 326 records across 25 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera cribellata is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Dysdera curviseta — EN

Taxonomy

• Scientific name: Dysdera curviseta Wunderlich, 1987
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii); D2) because the extent of occurrence (EOO) is 205.5 km² (below the EN threshold) and the area of occupancy (AOO) is 12 km² (below the EN threshold). It is known from 3 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to coastal urbanisation, tourism, agricultural intensification (invernaderos), invasive species (Dysdera crocata), pesticides, and climate change (sea-level rise, desertification).

Also qualifies as Vulnerable under D2 (AOO = 12 km², 3 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 205.5 km² (MCP); AOO = 12 km² (2×2 km grid).

Key localities: Fasnia; Granadilla; Tacoronte.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 17 records across 3 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera curviseta is a coastal endemic spider inhabiting lowland tabaibal-cardonal scrub, halophytic vegetation, and sandy fields on Tenerife. Recorded from sea level to ~300 m a.s.l. Active nocturnally; presumably preys on terrestrial isopods.

Habitat (IUCN)	Season	Suitability	Major importance
3.8 Shrubland → Mediterranean-type shrubby vegetation	Resident	Suitable	Yes
8.2 Desert → Temperate (coastal xerophytic)	Resident	Suitable	Yes
12.3 Marine Coastal/Supratidal → Coastal sand dunes	Resident	Suitable	—

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas (coastal urbanisation, land reclamation)	Ongoing	Majority (50-90%)	Rapid declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas (coastal resorts)	Ongoing	Majority (50-90%)	Rapid declines	1.1 Ecosystem conversion
2.1.2	Agriculture → Small-holder farming (invernaderos, banana plantations)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions → Recreational activities (off-road vehicles, beach use)	Ongoing	Minority (<50%)	Slow significant declines	1.3 Indirect ecosystem effects
8.1.2	Invasive non-native species → Named: Dysdera crocata; invasive plants	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.3.3	Pollution → Agricultural effluents → Herbicides and pesticides	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (sea-level rise, desertification)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera esquiveli — EN

Taxonomy

• Scientific name: Dysdera esquiveli Ribera & Blasco, 1986
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii); D2
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii); D2) because the extent of occurrence (EOO) is 307.2 km² (below the EN threshold) and the area of occupancy (AOO) is 20 km² (below the EN threshold). It is known from 5 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Also qualifies as Vulnerable under D2 (AOO = 20 km², 5 locations).

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 307.2 km² (MCP); AOO = 20 km² (2×2 km grid).

Key localities: Bucio, Cueva del; Cueva del Viento; El Sauzal; Felipe Reventón, Cueva de; Icod de Los Vinos; Icod de los Vinos; La Orotava; Los Silos; Sobrado, Cueva del; Viento, Cueva del.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 48 records across 8 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera esquiveli is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera guayota — EN

Taxonomy

• Scientific name: Dysdera guayota Ribera & Arnedo, 1999
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 918.5 km² (below the EN threshold) and the area of occupancy (AOO) is 40 km² (below the EN threshold). It is known from 10 location(s) on 2 islands (La Gomera, Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from 2 islands (La Gomera, Tenerife). EOO = 918.5 km² (MCP); AOO = 40 km² (2×2 km grid).

Key localities: Pilas, Montaña de las (La Mérica); Adeje; Arona; Conde, Roque del; Cristianos, Los; La Orotava; Lajas, Las; Lajas, Montaña de; Madre del Agua, Pista a; Taucho, Pinar de.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (La Gomera)	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 63 records across 13 unique localities. Populations on 2 islands (La Gomera, Tenerife) with no genetic exchange between them. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera guayota is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera iguanensis — EN

Taxonomy

• Scientific name: Dysdera iguanensis Wunderlich, 1987
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 3208.1 km² (below the EN threshold) and the area of occupancy (AOO) is 60 km² (below the EN threshold). It is known from 9 location(s) on 2 islands (Gran Canaria, Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from 2 islands (Gran Canaria, Tenerife). EOO = 3208.1 km² (MCP); AOO = 60 km² (2×2 km grid).

Key localities: Agua, Monte del; Aguirre, Monte; Anaga. Loc1; Bailadero, El; Bailadero, El (MSS); Bicora, Degollada de (mss); Carmen, Cruz del; Cochinos, Barranco de los; Hoya Ijuana, Pista a; Ijuana, Barranco de.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Gran Canaria)	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 187 records across 24 unique localities. Populations on 2 islands (Gran Canaria, Tenerife) with no genetic exchange between them. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera iguanensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera madai — EN

Taxonomy

• Scientific name: Dysdera madai Arnedo, 2007
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 483.9 km² (below the EN threshold) and the area of occupancy (AOO) is 28 km² (below the EN threshold). It is known from 6 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 483.9 km² (MCP); AOO = 28 km² (2×2 km grid).

Key localities: Agua, Monte del; Cochinos, Barranco de los; Cochinos, Barranco de los (mss); El Sauzal; La Orotava; Las Cañadas; Los Silos; Santa Cruz de Tenerife.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 59 records across 7 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera madai is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

---

Dysdera ratonensis — EN

Taxonomy

• Scientific name: Dysdera ratonensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Dysderidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 328.2 km² (below the EN threshold) and the area of occupancy (AOO) is 40 km² (below the EN threshold). It is known from 10 location(s) on a single island (La Palma), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (La Palma). EOO = 328.2 km² (MCP); AOO = 40 km² (2×2 km grid).

Key localities: Caños, Cueva de los ; Fuencaliente; Garafía; Honda de Gallegos, Cueva ; Mazo; Murciélagos II, Cueva de los; Palmeros, Cueva de los; Palmeros, Cueva de los ; Ratón, Cueva del.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (La Palma)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 43 records across 18 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Dysdera ratonensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Canarian Dysdera have undergone an adaptive radiation into subterranean habitats (lava tubes, MSS), with many species showing troglomorphism (eye reduction, depigmentation, elongated appendages). Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional de la Caldera de Taburiente. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Arnedo, M.A. & Ribera, C. (1999) Radiation of the genus Dysdera in the Canary Islands: the island of Tenerife. J. Arachnol. 27, 604–662.
• Arnedo, M.A. et al. (2007) The dark side of an island radiation: troglobitic Dysdera in the Canary Islands. Invertebr. Syst. 21, 623–660.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Troglohyphantes oromii — EN

Taxonomy

• Scientific name: Troglohyphantes oromii (Ribera & Blasco, 1986)
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

EN — Endangered

Criteria: B1a(i)b(iii); B2a(i)b(iii)
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Endangered (B1a(i)b(iii); B2a(i)b(iii)) because the extent of occurrence (EOO) is 301.0 km² (below the EN threshold) and the area of occupancy (AOO) is 28 km² (below the EN threshold). It is known from 7 location(s) on a single island (Tenerife), the population is severely fragmented [subcriterion a(i)] — each known site is an isolated subpopulation with no genetic exchange, and a continuing decline is inferred in the extent and quality of its habitat [subcriterion b(iii)] due to urbanisation near cave entrances, speleotourism, pollution (solid waste, stormwater), invasive Dysdera crocata, and climate change altering cave microclimate.

Geographic range

Endemic to the Canary Islands (Spain), known from a single island (Tenerife). EOO = 301.0 km² (MCP); AOO = 28 km² (2×2 km grid).

Key localities: Breveritas, Cueva de; Bucio, Cueva del; Chío, Cueva Grande de; Felipe Reventón, Cueva de; Labrada, Cueva de La; Mulo, Cueva del; Perdiz, Sima de la; Roques, Cueva de Los; San Marcos, Cueva de; Sobrado Inferior, Cueva del.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Tenerife)	Extant	Native	—	Resident

Distribution map

Click points for coordinates. Layer control (top-right): switch basemap or toggle AOO/EOO overlays.

Population

Known from 50 records across 11 unique localities. No quantitative population estimates available. Current population trend: Decreasing (inferred from habitat decline).

Habitat and ecology

Troglohyphantes oromii is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

May fall within Parque Nacional del Teide, Parque Rural de Anaga/Teno, or Corona Forestal. No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Centromerus fuerteventurensis — DD

Taxonomy

• Scientific name: Centromerus fuerteventurensis Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

DD — Data Deficient

Criteria: Data Deficient — no records in databases
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Data Deficient because there is insufficient georeferenced occurrence data (0 total record(s), 0 georeferenced) in the consulted databases to make a reliable assessment of its extinction risk. Targeted survey effort is required to determine distribution, population size, habitat preferences and specific threats.

Geographic range

Endemic to the Canary Islands. No georeferenced records available.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident

Distribution map

No georeferenced records available for mapping.

Population

No population estimates available. Current population trend: Unknown.

Habitat and ecology

Centromerus fuerteventurensis is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Lepthyphantes styx — DD

Taxonomy

• Scientific name: Lepthyphantes styx Wunderlich, 2011
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

DD — Data Deficient

Criteria: Data Deficient — no records in databases
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Data Deficient because there is insufficient georeferenced occurrence data (0 total record(s), 0 georeferenced) in the consulted databases to make a reliable assessment of its extinction risk. Targeted survey effort is required to determine distribution, population size, habitat preferences and specific threats.

Geographic range

Endemic to the Canary Islands. No georeferenced records available.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident

Distribution map

No georeferenced records available for mapping.

Population

No population estimates available. Current population trend: Unknown.

Habitat and ecology

Lepthyphantes styx is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Spermophorides flava — DD

Taxonomy

• Scientific name: Spermophorides flava Wunderlich, 1992
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Pholcidae
• Common names: No widely used common name

Red List status

DD — Data Deficient

Criteria: Data Deficient — 1 records, none georeferenced
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Data Deficient because there is insufficient georeferenced occurrence data (1 total record(s), 0 georeferenced) in the consulted databases to make a reliable assessment of its extinction risk. Targeted survey effort is required to determine distribution, population size, habitat preferences and specific threats.

Geographic range

Endemic to the Canary Islands. No georeferenced records available.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident
Spain → Canary Islands (Gran Canaria)	Extant	Native	—	Resident

Distribution map

No georeferenced records available for mapping.

Population

No population estimates available. Current population trend: Unknown.

Habitat and ecology

Spermophorides flava is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Walckenaeria subterranea — DD

Taxonomy

• Scientific name: Walckenaeria subterranea Wunderlich, 2011
• Higher taxonomy: Animalia — Arthropoda — Arachnida — Araneae — Linyphiidae
• Common names: No widely used common name

Red List status

DD — Data Deficient

Criteria: Data Deficient — no records in databases
Categories & Criteria version: 3.1 · Guidelines version: 16 (March 2024)

Assessment information

• Assessor(s): [to be completed]
• Reviewer(s): [to be completed]
• Contributor(s): Arnedo, M.A.; Macías-Hernández, N.; Oromí, P.
• Date of assessment: 17 abril 2026

Assessment rationale

This species is assessed as Data Deficient because there is insufficient georeferenced occurrence data (0 total record(s), 0 georeferenced) in the consulted databases to make a reliable assessment of its extinction risk. Targeted survey effort is required to determine distribution, population size, habitat preferences and specific threats.

Geographic range

Endemic to the Canary Islands. No georeferenced records available.

Biogeographic realm: Palearctic

Countries of occurrence

Country	Presence	Origin	Formerly bred	Seasonality
Spain	Extant	Native	—	Resident

Distribution map

No georeferenced records available for mapping.

Population

No population estimates available. Current population trend: Unknown.

Habitat and ecology

Walckenaeria subterranea is a cave-dwelling (troglobitic) endemic spider of the Canary Islands. Inhabits volcanic lava tubes and subterranean cavities. Specialised predator of cave-dwelling isopods.

Habitat (IUCN)	Season	Suitability	Major importance
7.1 Caves & Subterranean Habitats → Caves	Resident	Suitable	Yes
7.2 Caves & Subterranean Habitats → Other (MSS)	Resident	Suitable	Yes

System: Terrestrial · Generation length: Unknown (estimated 2–4 years)

Use and trade

Not used or traded.

Threats

Code	Threat	Timing	Scope	Severity	Stresses
1.1	Residential & commercial development → Housing & urban areas	Ongoing	Minority (<50%)	Slow significant declines	1.1 Ecosystem conversion; 1.2 Ecosystem degradation
1.3	Residential & commercial development → Tourism & recreation areas	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
6.1	Human intrusions & disturbance → Recreational activities (caving, speleotourism)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation; 1.3 Indirect ecosystem effects
7.3	Natural system modifications → Other ecosystem modifications (entrance sealing, quarrying)	Ongoing	Minority (<50%)	Rapid declines	1.1 Ecosystem conversion
8.1.2	Invasive non-native species → Named: Dysdera crocata (competing in lava tubes)	Ongoing	Unknown	Unknown	2.1 Species mortality; 2.3.2 Competition
9.1.1	Pollution → Domestic & urban waste water → Sewage (stormwater run-off into caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
9.4	Pollution → Garbage & solid waste (illegal dumping in caves)	Ongoing	Minority (<50%)	Slow significant declines	1.2 Ecosystem degradation
11.1	Climate change → Habitat shifting & alteration (cave microclimate: T°, humidity)	Ongoing	Whole (>90%)	Slow significant declines	1.2 Ecosystem degradation
11.2	Climate change → Droughts	Ongoing	Whole (>90%)	Unknown	1.2 Ecosystem degradation

Conservation

No specific management plans exist for cave-dwelling arachnid fauna. Not listed in Catálogo Español de Especies Amenazadas.

Code	Action
1.1	Land/water protection → Site/area protection
1.2	Land/water protection → Resource & habitat protection
2.1	Land/water management → Site/area management
2.3	Land/water management → Habitat & natural process restoration
3.1	Species management → Species management
4.3	Education & awareness → Awareness & communication
5.1.2	Law & policy → National level legislation
5.1.3	Law & policy → Sub-national level

Research needed

Code	Research	Priority
1.2	Research → Population size, distribution & trends	High
1.3	Research → Life history & ecology	High
1.5	Research → Threats	High
3.1	Monitoring → Population trends	High
3.4	Monitoring → Habitat trends	Medium

Bibliography

• Barrientos, J.A. et al. (2018) A new Troglohyphantes from the Canary Islands. Rev. Ibér. Aracnol. 32, 25–32.
• Oromí, P. et al. (2001) Conservación de la fauna invertebrada cavernícola (Tenerife, La Palma, El Hierro). Proyecto LIFE.
• Wunderlich, J. (1991) Die Spinnen-Fauna der Makaronesischen Inseln. Beitr. Araneol. 1, 1–619.
• IUCN (2024) Guidelines for Using the IUCN Red List Categories and Criteria, v16.
• IUCN (2022) Threats Classification Scheme, v3.3.

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Methods

Data sources

Occurrence data compiled from:

1. Spreadsheet Canarian Dysdera (Arnedo Lab, UB) — primary source for Dysdera spp. (9,916 records, 6,303 georeferenced).
2. ER_ubic_DZUL (Departamento de Zoología, ULL) — museum specimen records with GPS/UTM (3,334 spider records).
3. Nuevos registros DZUL — additional recent records.
4. DataBase Unificado (Sep 2022) — presence/absence per cave.
5. DataBase AAMSS — cave arthropod database (Oromí et al., LIFE Project).
6. Species-specific curated files: Dysdera ambulotenta (KMZ), D. labradaensis, D. unguimmanis, D. gollumi.

After deduplication and synonym resolution, 1,458 records of the 36 target species were retained.

Spatial analyses

• EOO: Minimum convex polygon (MCP) of unique georeferenced points, area computed in UTM zone 28N (EPSG:32628). Where EOO < AOO, EOO is set equal to AOO per Guidelines v16 §4.9.
• AOO: Number of occupied 2 × 2 km grid cells multiplied by 4 km² (reference scale, Guidelines v16 §4.10.3).
• Locations (IUCN sense): Single-linkage hierarchical clustering on pairwise geodesic distances at a 2 km threshold — approximately the spatial extent at which one plausible threat could affect all individuals.

Criterion B application

Assessment of Criterion B follows Guidelines v16 strictly:

1. Subcriterion a(i) — severely fragmented (§4.8): applied when ≥ 2 locations exist, because troglobitic or strictly coastal spiders have effectively zero gene flow between sites.
2. Subcriterion a(ii) — few locations: applied only when 1 location is known.
3. Subcriterion b(iii) — inferred continuing decline in habitat (§4.6): supported by the documented threats listed in each species’ threat table (IUCN Threats Classification v3.3).
4. Criterion D2: applied when AOO < 20 km² OR locations ≤ 5 (v16 §8.3).

Software

R (≥ 4.3) with packages sf, leaflet, htmlwidgets, base64enc, jsonlite, dplyr, knitr. Maps use WGS 84 (EPSG:4326) for display and UTM 28N (EPSG:32628) for area calculations.

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Document generated with R Markdown on 17 abril 2026, 10:44.