Pyrgulopsis torrida Hershler, Liu, Babbitt, Kellogg & Howard

Hershler, Robert, Liu, Hsiu-Ping, Babbitt, Caitlin, Kellogg, Michael G. & Howard, Jeanette K., 2016, Three new species of western California springsnails previously confused with Pyrgulopsisstearnsiana (Caenogastropoda, Hydrobiidae), ZooKeys 601, pp. 1-19 : 9-11

Taxon classification Animalia Littorinimorpha Hydrobiidae

Pyrgulopsis torrida Hershler, Liu, Babbitt, Kellogg & Howard sp. n. Figs 3C, 6

Pyrgulopsis stearnsiana .- Hershler and Liu 2010 (in part).

Types.

Holotype, SBMNH 74238, Little Sycamore Canyon, creek 3.2 km up flow from Hwy 1, Ventura County, California, 34.07509°N, 118.95508°W, 11/11/1961, W. B. Miller. Paratypes, SBMNH 460492 (ca. 200 dried shells), from same lot.

Referred material.

California. Ventura County: SBMNH 74236, * USNM 1120443, ibid, 9/9/1956, 10/21/2008, respectively.

Diagnosis.

A medium-sized congener (maximum shell height, 2.8 mm) having an ovate-conic shell. Distinguished from Pyrgulopsis stearnsiana by its shorter penial filament and larger terminal gland.

Description.

Shell (Fig. 6 A–B, Table 5) ovate-conic, whorls 4.00. Teleoconch whorls medium convex, narrowly shouldered. Aperture ovate, slightly angled above; parietal lip complete, nearly straight, narrowly adnate adapically or slightly disjunct, thin or slightly thickened; umbilicus small. Outer lip thin, orthocline. Teleoconch smooth or sculptured with weak spiral striae.

Operculum (Fig. 6 C–D) as for genus; portion of attachment scar margin slightly thickened on inner side. Radula (Fig. 6 E–G) as for genus; dorsal edge of central teeth concave, lateral cusps three–six, basal cusps one to (rarely) two. Lateral teeth having two–four cusps on inner and three–five cusps on outer side. Inner marginal teeth with 19-24 cusps, outer marginal teeth with 21-27 cusps. Radula data are from SBMNH 460492.

Penis (Fig. 3C) small, filament weakly pigmented or pale, filament short, narrow, horizontal, weakly tapering; lobe small, rectangular, horizontal; terminal gland fairly large, narrow, overlapping dorsal and ventral edges of lobe. Penial data are from USNM 1120443 (2 specimens).

Etymology.

The species name is an adjective derived from the New Latin torridus, meaning dry or parched, and refers to the recent desiccation of the stream in Little Sycamore Canyon. We propose "Little Sycamore pyrg" as the common name for this species.

Distribution.

Endemic to the type locality, a small, shallow stream which runs for about 1.6 km. Snails were collected from the mud bottoms of a series of small puddle-like pools along the middle section of the stream.

Conservation status.

Pyrgulopsis torrida was found only rarely in the Little Sycamore Canyon creek in 2000. The entirely length of the canyon was dry when re-visited in 2015, suggesting that this population may now be extirpated.