Pyrgulopsis ventricosa

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	MOLLUSCA	GASTROPODA	LITTORINIMORPHA	HYDROBIIDAE

Scientific Name:

Pyrgulopsis ventricosa

Species Authority:

Hershler, 1995

Common Name/s:

English

–

Clear Lake Pyrg

Synonym/s:

Pomatiopsis intermedia Cooper, 1876

Assessment Information [top]

Red List Category & Criteria:	Critically Endangered B1ab(i,ii,iii,iv)+2ab(i,ii,iii,iv) ver 3.1
Year Published:	2012
Assessor/s:	Cordeiro, J. & Perez, K.
Reviewer/s:	Bohm, M., Collen, B. & Seddon, M.
Contributor/s:	Dyer, E., Soulsby, A.-M., Whitton, F., Kasthala, G., McGuinness, S., Milligan, HT, De Silva, R., Herdson, R., Thorley, J., McMillan, K., Collins, A., Offord, S., Duncan, C. & Richman, N.
Justification: Pyrgulopsis ventricosa has been assessed as Critically Endangered under criterion B1ab(i,ii,iii,iv) and B2ab(i,ii,iii,iv) due to its restricted distribution with an extent of occurrence of 17 km² and an area of occupancy which is less than 10 km². It had a historically more widespread distribution but is now only found in one location and continues to be impacted by water loss, diversion and development. This is causing continuing declines in extent of occurrence, area of occupancy, habitat quality and number of subpopulations.

Geographic Range [top]

Range Description:	This species is restricted to the Seigler Creek drainage in the south end of the Clear Lake basin, in California (Hershler 1995). Its extent of occurrence is estimated as less than 20 km²and its area of occupancy is likely to be less than 10 km².
Countries:	Native: United States (California)
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	This species was commonly found in the stream where it is endemic, although historical records suggest as recently as 1970 it was more widespread in the Clear Lake region (Hershler 1995).
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	This species inhabits springs and small spring-fed streams, where it is found on vegetation (Hershler 1995).
Systems:	Freshwater

Threats [top]

Major Threat(s):	The only locality of this species, a small spring-fed stream, has been diverted and additionally impacted by human activities (Hershler 1995). Due to its highly restricted distribution, this snail is in danger of extinction from even minor alterations to its habitat.

Major Threat(s):

The only locality of this species, a small spring-fed stream, has been diverted and additionally impacted by human activities (Hershler 1995). Due to its highly restricted distribution, this snail is in danger of extinction from even minor alterations to its habitat.

Conservation Actions [top]

Conservation Actions:	This species has a Global Heritage Status of G1 - Critically Imperilled (NatureServe 2009). Due to its highly restricted nature, protection of both this species and its habitat is essential to the continuing viability of the known population(s).

Conservation Actions:

This species has a Global Heritage Status of G1 - Critically Imperilled (NatureServe 2009). Due to its highly restricted nature, protection of both this species and its habitat is essential to the continuing viability of the known population(s).

Citation:	Cordeiro, J. & Perez, K. 2012. Pyrgulopsis ventricosa. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 18 May 2013.
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