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Thrigmopoeus truculentus 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Arachnida Araneae Theraphosidae

Scientific Name: Thrigmopoeus truculentus Pocock, 1899
Common Name(s):
English Karwar Large Burrowing Spider
Taxonomic Notes: There is some confusion between Thrigmopoeus truculentus and T. insignis since the two have overlapping distribution. Taxonomically, the difference is noticeable in size, colour, chelicerae and maxillary lyra under a stereomicroscope.

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2008
Date Assessed: 2008-01-01
Assessor(s): Molur, S., Siliwal, M. & Daniel, B.A.
Reviewer(s): Spector, S. & Mason, T. (Terrestrial Invertebrates Red List Authority)
Justification:
The species is recorded mostly from the Karnataka part of the Western Ghats and from southern Maharashtra. It could also occur in Goa. It occurs in only certain areas with a very patchy distribution. The extent of occurrence of this species has been estimated as slightly more than 20,000 km² (approximately 25,000 km²). Area of occupancy has not been estimated. The habitat where the species occurs is severely fragmented and degraded due to road widening, cutting of trees, bund maintenance, soil erosion and other kinds of human interference. In protected areas, the situation is better. It is assumed that the area of habitat has decreased over the years. There is evidence of trade in this species as seen on internet web sites of traders advertising and hobbyists exchanging notes. Although the volume of trade is not known, this along with decreasing habitat quality and area of occupancy make the species being close to Vulnerable. It is categorized as Near Threatened since it misses the restricted distribution criteria.

Geographic Range [top]

Range Description:Endemic to the Western Ghats of Karnataka and Maharashtra, this species is found in Amboli in the north and Madikeri in the south at an altitudinal range of 200 to 1,000 m. The extent of occurrence encompassing known and inferred distribution is around 25,000 km², while the area of occupancy has not been estimated. In Karnataka: Karwar in Uttara Kannada district (Pocock 1899, 1900), Agumbe in Chickamagalur district (B. Arthur and C. Shankar pers. comm.), Madikeri, Somwarpet, Virajpet and Bhagamandala in Coorg district (S. Molur pers. comm.); in Maharashtra: Amboli (15°57'37"N, 73°59'58"E) in Kolhapur district (V. Giri pers. comm.).
Countries occurrence:
Native:
India (Karnataka, Maharashtra)
Additional data:
Lower elevation limit (metres):200
Upper elevation limit (metres):1000
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Population estimates are unknown. However, this species is relatively commonly found in some areas, but overall it is not so common in its distribution range. It has been recorded from less than 10 locations. The locations are severely fragmented due to human interference such as road widening, bund maintenance, fire, soil extraction, and related threats such as soil erosion.
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:This ground spider is primarily found in moist deciduous and evergreen forests. The species occurs very patchily, with burrows on soil bunds with adequate vegetation cover. Burrows occasionally occur on flat ground. In examining the burrow aggregations, we have found the composition to have one adult female with several juveniles and sub adults from different clutches in individual burrows close to the adult female's burrow. Observations on population indicates a very high mortality rate in juveniles/subadults, of more than 95% in the first two years. Dispersal rates are unknown. Healthy population of spiders/burrows are usually found in areas with very little disturbance.
Systems:Terrestrial

Threats [top]

Major Threat(s): Habitat loss and degradation are major threats. Road widening is most common threat for these ground theraphosid spiders. Many spiders get killed and their burrows get destroyed during this process. Mud bund maintenance in forested areas along with man made fires and soil erosion are other threats. In more open areas, soil extraction and erosion are the reasons for disappearance of these spiders. An additional threat to the species is collection for the international pet trade market. Although the volume of trade is unknown, we have reports of some locals being involved and paid by European traders to collect and supply either personally, or through courier services. This species is advertised on certain internet sites.

Conservation Actions [top]

Conservation Actions: The species has not been reported from protected areas.

Citation: Molur, S., Siliwal, M. & Daniel, B.A. 2008. Thrigmopoeus truculentus. The IUCN Red List of Threatened Species 2008: e.T63673A12705887. . Downloaded on 24 September 2018.
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