A Review of the North American Freshwater Snail Genus Pyrgulopsis

66
pouch-like, narrow, medium length, positioned just anterior to
or slightly overlapping bursa copulatrix.
TYPE LOCALITY.—Brown Spring, Yavapai County, Arizona
(T 12N, R 9E, SE1/4 sec. 23). Holotype, USNM 859045;
paratypes, USNM 859046.
DISTRIBUTION.—Endemic to type locality, Verde River
drainage.
MATERIAL EXAMINED.—USNM 850290 (topotypes).
Pyrgulopsis stearnsiana (Pilsbry, 1899)
Paludestrina stearnsiana Pilsbry, 1899:122—Walker, 1918:139—Baker,
1964:176 [in part].
Fontelicella stearnsiana.—-Gregg and Taylor, 1965:108.—Taylor, 1975:180;
1981:152.—Burch, 1982:26—Turgeon et al., 1988:61.
Pyrgulopsis stearnsiana.—Hershler and Thompson, 1987:30.
DIAGNOSIS.—Shell ovate-conic, medium-sized, weakly umbilicate.
Penial filament elongate, lobe very short Penial
ornament a circular terminal gland.
DESCRIPTION.—Shell (Figure 25g) ovate-conic; height,
2.5-3.1 mm; whorls, 4.5-5.0. Early protoconch weakly
punctate, otherwise near smooth, Teleoconch whorls moderately
convex, slightly shouldered; sculpture of weak growth
lines. Aperture narrowly adnate to slightly separated from the
body whorl. Inner lip complete, thin; columellar lip sometimes
slightly reflected. Outer lip near orthocline. Umbilicus rimate
to weakly perforate. Periostracum light brown.
Operculum (Figure 25h,i) ovate, amber, darker centrally;
nucleus highly eccentric; dorsal surface weakly frilled. Attachment
scar margin thickened all around, broadly so along most
of inner edge (sometimes all around); callus weak.
Central radular tooth (Figure 40a) with moderately indented
dorsal edge; lateral cusps, 5-6; central cusp pointed, tonguelike,
slightly broader and longer than laterals; basal cusps, 1,
large, with moderate dorsal support Basal process narrow;
basal sockets deep. Lateral margins slightly thickened; neck
weak-absent
Cephalic tentacles, snout pale to moderate gray-black. Foot
pale to light gray. Opercular lobe dark along margins,
especially sides. Neck pale-light. Pallial roof, visceral coil
black.
Ctenidial filaments, 19, tall, broad. Osphradium centered
slightly posterior to middle of ctenidial axis. Kidney opening
white. Stomach caecum large.
Testis, 2 whorls, overlapping stomach to edge of style sac.
Prostate gland with large (25%) pallial section; pallial vas
deferens with proximal kink. Penis (Figure 51b) medium-sized;
filament almost as long as base, tapering; lobe very short to
near-absent, narrow. Terminal gland small, circular, borne
along distal edge of lobe (ventral surface). Filament dark.
Ovary, 0.5-0.75 whorl, overlapping entirety of posterior
stomach chamber. Pallial albumen gland large (25%-3O%).
Capsule gland as long as albumen gland. Genital aperture a
broad, subterminal slit with short vestibule. Coiled oviduct a
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
posterior oblique coil overlapping broader, horizontal loop
slightly behind pallial wall. Oviduct and bursal duct join
slightly behind pallial wall. Bursa copulatrix ovoid, medium
length and width, with 65%-75% of length posterior to gland.
Bursa duct narrow, shallowly embedded in albumen gland
distally, medium length. Seminal receptacle pouch-like, long
(60%), lateral to proximal bursal duct or slightly overlapping
anterior bursa copulatrix.
TYPE LOCALITY.—Near Oakland (California). Lectotype
(Baker, 1964:176), ANSP 27961; paralectotypes, ANSP
396667.
DISTRIBUTION.—Central, coastal California, from Sonoma
County to Monterey County (Taylor, 1981). Sierra Nevada
populations mentioned by Taylor require confirmation.
MATERIAL EXAMINED.—USNM 873366, USNM 874181,
Palo Seco creek, terminal pool, Alameda County, California.
Pyrgulopsis thermalis (Taylor, 1987), new combination
Fontelicella thermalis Taylor. 1987:28, fig. 13.
"Fontelicella" thermalis.—USDI, 1991b:58819.
DIAGNOSIS.—Shell globose to broadly conical, small,
umbilicate. Penial filament medium length, lobe short. Penial
ornament an elongate penial gland, curved Dgl, Dg2; elongate,
transverse, curved terminal gland; and ventral gland. Dorsal
glands sometimes fused.
DESCRIPTION.—Shell (Figure 26a) globose to broadly
conical; height, 1.5-2.0 mm; whorls, 3.0-3.5. Early protoconch
very weakly punctate, later portion smooth. Teleoconch
whorls moderately convex, strongly shouldered; sculpture of
moderate growth lines. Aperture large, adnate to body whorl.
Inner lip complete, highly thickened (forming broad callus).
Outer lip thick, strongly prosocline. Umbilicus near absent to
perforate. Periostracum tan, thin.
Operculum (Figure 26b,c) ovate, amber, darkened centrally;
nucleus slightly eccentric; dorsal surface weakly frilled.
Attachment scar margin broadly thickened along inner edge
(sometimes to nucleus); outer edge slightly thickened or near
smooth; callus well developed, elongate.
Central radular tooth (Figure AOb) with moderately indented
dorsal edge; tooth face near square; lateral cusps, 4-5; central
cusp pointed, extremely elongate, considerably longer than
laterals; basal cusps, 1, small, short, with strong dorsal support
Basal process broad; basal sockets deep. Lateral margins
slightly thickened; neck moderate.
Cephalic tentacles, snout light-dark brown. Foot usually
light, sometimes dark. Opercular lobe dark along anterior edge,
sometimes moderately pigmented along entire margin. Neck
light-moderate, with central unpigmented strip. Pallial roof,
visceral coil usually dark (near uniformly) brown-black; mantle
pigment rarely light
Ctenidial filaments, 15, short, medium width. Osphradium
centered slightly posterior to middle of ctenidium. Kidney
opening unthickened. Stomach caecum small, narrow.