Pyrgulopsis cedrosensis (Pilsbry 1927)

Pyrgulopsis cedrosensis (Pilsbry, 1927)

Paludestrina cedrosensis Pilsbry, 1927:188, fig. 3.

Fontelicella (Fontelicella) cedrosensis.—Gregg and Taylor, 1965:108.

Fontelicella cedrosensis.—Taylor, 1975:55.

DIAGNOSIS.—Shell ovate-conic, small to medium-sized. Penial lobe, filament medium length. Penial ornament unknown.

DESCRIPTION.—Shell (Figure 11d) ovate-conic; height, 1.7–2.3 mm; whorls, 3.5–4.0. Apex near-flat, appearing smooth, but eroded. Teleoconch whorls convex, often shouldered; sculpture of weak growth lines. Aperture large, ovate, usually slightly separated from body whorl. Inner lip complete, slightly thickened. Outer lip orthocline to slightly prosocline. Umbilicus near absent to shallowly perforate. Periostracum very thin, virtually colorless.

Operculum (Figure 11e,f) ovate, near-colorless except for light amber nuclear region; nucleus slightly eccentric; dorsal surface smooth. Attachment scar margin weak-moderately thickened all around; callus weak.

Central radular tooth (Figure 34a) with moderately indented dorsal edge; lateral cusps, 5; central cusp pointed, elongate, slightly broader than laterals; basal cusps, 1, elongate-triangular, with weak dorsal support. Basal process with very narrow distal section; basal sockets deep. Lateral margins slightly thickened; neck weak.

Head-foot, visceral coil dark brown-black.

Penial filament medium length, tapered; lobe about equal to filament in length, broad. Proximal filament with scattered black pigment.

TYPE LOCALITY.—Bernsteins Spring, east side of Cedros Island, Baja California Norte, Mexico. Holotype, CAS 66145; paratypes, CAS 66146, ANSP 141408.

DISTRIBUTION.—Probably was endemic to Cedros Island (one or more springs). The type locality and other springs on this island were visited in 1991 and found to be devoid of hydrobiid snails.