A Review of the North American Freshwater Snail Genus Pyrgulopsis

NUMBER 554 41
visceral coil black.
Ctenidial filaments, 36, very tall, broad. Osphradium
centered posterior to middle of ctenidial axis. Kidney opening
white. Stomach caceum prominent, triangular, darkly pigmented.
Tbstis, 1.5 whorls, overlapping stomach to edge of style sac.
Prostate gland very broad posteriorly, thickened, with large
pallial section (40%). Pallial vas deferens thickened, with
proximal kink. Penis (Figure 46/) very large, extending well
beyond edge of mantle collar, base elongate-rectangular,
filament very short, narrow, tapering; lobe large, broad. Dgl
elongate, extending along right edge (sometimes slightly
overlapping proximal filament), to mid-penis; gland curving
inward posteriorly where weakly raised; smaller glandular dots
sometimes present to left of above. Dg2 usually short,
sometimes fused with Dg3, sometimes fragmented into or
accompanied by several short strips; Dg3 borne on welldefined
lobule. Terminal gland elongate, transverse, straight,
borne along distal edge of lobe, usually ventrally. Ventral gland
small, stalked, centrally positioned (sometimes absent). Filament
darkly pigmented internally.
Ovary, 1.5 whorls, overlapping stomach to edge of style sac.
Pallial albumen gland large (30%). Capsule gland longer than
albumen gland. Genital aperture a short terminal slit; vestibule
very short or absent. Coiled oviduct a horizontal loop (kinked
proximally) well behind pallial wall near posterior end of
albumen gland. Oviduct and bursal duct join anterior to oviduct
coil behind pallial wall. Bursa copulatrix ovoid, about as long
and as wide as albumen gland, with most of length (about 70%)
posterior to gland. Bursal duct medium width, very short
Seminal receptacle finger-like, short, overlapping anterior
bursa copulatrix, extending to posterior edge of albumen gland.
TYPE LOCALITY.—South of Burns, Oregon. Holotype,
ANSP 145951; paratypes, ANSP 396668.
DISTRIBUTION.—Hamey Lake basin, Malheur River drainage,
Harney County, Oregon (Gregg and Taylor, 1965; Taylor
and Smith, 1981).
REMARKS.—Distinguished from similar P. idahoensis (from
Snake River) by broader shell; simple, circular oviduct coil;
consistent presence of ventral penial gland; elongate, ovate
bursa copulatrix; dorsal position of bursal duct, and anterior
position of seminal receptacle.
Recent field survey by the author (and T. Frest, pers. comm.)
indicated that this species is probably extinct in its type locality
area. Anatomical data were obtained from material collected
from the western Harney Lake basin.
MATERIAL EXAMINED.—USNM 874386, Lower Sizemore
Spring, Warm Springs Valley, Harney Lake basin, Harney
County, Oregon (T 27S, R 29E, NW1/4 sec. 15).
Pyrgulopsis idahoensis (Pilsbry, 1933)
Amnicola idahoensis Pilsbry. 1933:11, pi. 2: figs, 3, 4, 5.—Henderson,
1936*137, fig. 6.—Branson et al., 1966:145.
Fontelicella (Natricola) idahoensis.—Gregg and Taylor, 1965:109.—Burch,
1982:26, figs. 241,242.
Fontelicella idahoensis.—Taylor, 1966a:73; 1975:101.—Tbrgeon et al.,
1988:61.—USDI, 1991b:58819.
Pyrgulopsis idahoensis.—-Hershler and Thompson, 1987:29.—Bowler and
Frest, 1992:30.—Frest and Bowler, 1992:45.—USDI, 1992:59244.
DIAGNOSIS.—Shell narrow to elongate-conic, large, weakly
umbilicate. Penial filament and lobe medium length; lobe
broad. Penial ornament an elongate Dgl, short Dg2, Dg3 borne
on lobule; elongate, transverse terminal gland, and sometimes
a ventral gland. Dorsal glands sometimes fused.
DESCRIPTION.—Shell (Figure \6e) narrowly- to elongateconic;
height, 5-7.5 mm; whorls, 5-6. Protoconch very weakly
punctate near apex, otherwise smooth except for several faint
spiral lines on later portion; often eroded, whitish. Teleoconch
whorls slightly to moderately convex, often with weak to
strong peripheral angulation; sculpture of weak growth lines
and numerous, faint spiral lines. Aperture ovate, broadly adnate
to or slightly separated from body whorl. Inner lip complete,
medium thickness; columellar lip with weak or no reflection.
Outer lip prosocline. Umbilicus absent to narrowly rimate.
Periostracum olive-tan.
Operculum (Figure 16/,g) ovate, generally light amber, but
dark red in nuclear region and along inner edge; nucleus
slightly eccentric; dorsal surface weakly frilled. Attachment
scar margin highly thickened all around, broadly so between
nucleus and mid-point of inner edge (sometimes slightly raised
between nucleus and inner edge); callus moderate.
Central radular tooth (Figure 36ft) with moderately indented
dorsal edge; tooth face square; lateral cusps, 4-5; central cusp
rounded, considerably broader, slightly longer than laterals;
basal cusps, 1, short, with strong dorsal support Basal process
medium width; basal sockets deep. Lateral margins thickened;
neck very weak-absent.
Cephalic tentacles, snout light-moderate brown. Foot pale or
moderate brown along anterior edge. Opercular lobe pale or
with dark sides. Neck pale-light Pallial roof, visceral coil
black.
Ctenidial filaments, 35, very tall, broad. Osphradium
elongate (35%), centered slightly posterior to middle of
ctenidial axis. Kidney opening white. Stomach caecum broadly
triangular, large.
Testis, 2 whorls, overlapping anterior stomach chamber.
Prostate gland large, posterior section extremely broad; pallial
section large (27%). Pallial vas deferens with strong proximal
kink. Penis (Figure 47a) large; base broadly rectangular,
filaifient medium length, narrow; lobe about as long as
filament, broad. Dgl crossing penis width at mid-length to
outer edge and extending onto base of filament, borne on
swelling proximally; small glandular dots sometimes present to
left of above. Dg2 usually short, sometimes fused with Dg3;
Dg3 large (sometimes fragmented into smaller units), borne on
well-defined lobule. Terminal gland transverse, narrowly
elongate, straight, positioned along distal edge of lobe, usually
largely ventral. Ventral penis with central swelling rarely