A Review of the North American Freshwater Snail Genus Pyrgulopsis

NUMBER 554 65
Pyrgulopsis simplex Hershler, 1988
Pyrgidopsis simplex Hershler in Hershler and Landye, 1988:32, figs. 21g-j,
26b, 27, 28.—USDI, 1991b:58822.
DIAGNOSIS.—Shell ovate-conic, medium-sized, umbilicate.
Penial filament medium length, lobe short. Penial ornament a
variably shaped terminal gland.
DESCRIPTION.—Shell (Figure 25a) ovate-conic; height,
2.0-2.5 mm; whorls, 3.5-4.25. Early protoconch finely
punctate, later portion near smooth except for weak adapical
spiral striae. Teleoconch whorls slightly convex, shouldered;
sculpture of weak growth lines. Aperture usually separated
from body whorl, sometimes narrowly adnate. Inner lip
complete, thickened; columellar lip reflected. Outer lip slightly
thinner, weakly prosocline. Umbilicus near absent to broadly
rimate. Periostracum light brown.
Operculum (Figure 25b,c) ovate, light amber, nucleus highly
eccentric; dorsal surface smooth. Attachment scar margin
slightly thickened along portion of inner edge; callus moderately
developed.
Central radular tooth (Figure Z9e) with moderately indented
dorsal edge; tooth face near-square; lateral cusps, 4-5; central
cusp pointed, narrow, slightly longer and broader than laterals;
basal cusps, 1, medium-sized, with moderate dorsal support.
Basal process narrow; basal sockets deep. Lateral margins
thickened; neck moderate.
Head-foot pale except for internal black pigment patch on
sides of neck and (sometimes) black internal streak along inner
edge of opercular lobe. Pallial roof black; visceral coil black.
Ctenidial filaments, 18, medium height and width. Osphradium
centered slightly posterior to middle of ctenidial axis.
Kidney opening white. Stomach caecum very small.
Testis, 1.5 whorls, overlapping stomach to edge of style sac.
Prostate gland small, ellipsoidal, with short pallial section;
pallial vas deferens simple. Penis (Figure 50/) medium-sized;
base elongate-rectangular, filament medium length, tapering;
lobe short, slightly narrower than base. Terminal gland
medium-sized, variably shaped, borne along distal edge of lobe
(ventral surface). Filament dark.
Ovary, 0.5 whorl, overlapping posterior stomach chamber.
Pallial albumen gland short (24%). Capsule gland as long as
albumen gland. Genital aperture a broad subterminal pore with
short vestibule. Coiled oviduct a horizontal loop. Oviduct and
bursal duct join just behind pallial wall. Bursa copulatrix ovoid,
short (33%), medium width, with 45%-60% of length
posterior to gland. Bursal duct medium width, shallowly
embedded in albumen gland, about as long as bursa copulatrix.
Seminal receptacle pouch-like, slender, short, overlapping
anteriormost bursa copulatrix or proximal bursal duct
TYPE LOCALITY.—Spring near Strawberry, Gila County,
Arizona (T 12N, R 7E, SW1/4 sec. 22). Holotype, USNM
859049; paratypes, USNM 859050.
DISTRIBUTION.—Springs along Fossil Creek, lower Verde
River drainage.
MATERIAL EXAMINED.—USNM 847236 (topotypes).
Pyrgulopsis sola Hershler, 1988
Pyrgulopsis solus Hershler in Hershler and Landye, 1988:30, figs. 21d-f, 24,
25, 26a.—USDI, 1991b:58822.
DIAGNOSIS.—Shell ovate-conic, small, weakly umbilicate.
Penial filament medium length, lobe short, often bifurcate
distally. Penial ornament a transverse, often fragmented
terminal gland.
DESCRIPTION.—Shell (Figure 25d) ovate-conic; height,
1.4-2.0 mm; whorls, 3.5-4.0. Early protoconch weakly
punctate, later portion near-smooth. Teleoconch whorls moderately
convex, often slightly shouldered; sculpture of moderate
growth lines. Aperture usually slightly separated from body
whorl, sometimes narrowly adnate. Inner lip complete, thickened;
columellar lip strongly reflected. Outer lip thick, slightly
prosocline. Umbilicus narrowly rimate or weakly perforate.
Periostracum light amber.
Operculum (Figure 25e,f) broadly ovate, amber, nucleus
slightly eccentric; dorsal surface frilled. Attachment scar
margin thickened all around, broadly so along inner edge;
callus moderate.
Central radular tooth (Figure 39/) with weak-moderately
indented dorsal edge; tooth face square; lateral cusps, 6; central
cusp pointed, narrow, slightly longer and wider than laterals;
basal cusps, 1, small to medium-sized, with strong dorsal
support. Basal process narrow; basal sockets deep. Lateral
margins thickened; neck weak.
Cephalic tentacles pale or with scattered light brown patches
on proximal half. Snout pale to moderate brown. Foot pale.
Opercular lobe darkly streaked along inner edge. Neck with
light-dark internal gray-black pigment Pallial roof, visceral
coil moderate to (more commonly) dark brown-black.
Ctenidial filaments, 15, medium height and width. Osphradium
centered posterior to middle of ctenidial axis. Kidney
opening slightly thickened. Stomach caecum medium-sized.
Testis, 1.5 whorls, overlapping stomach to edge of style sac.
Prostate gland with large (32%) pallial section; pallial vas
deferens simple. Penis (Figure 50a) very small; filament
medium length, narrow; lobe short, broad, often distally
bifurcate. Terminal gland large, transverse, borne along distal
edge of lobe (both surfaces), usually fragmented into two units.
Filament dark.
Ovary, 0.5-0.75 whorl, very slightly overlapping posterior
stomach chamber. Pallial albumen gland short (23%). Capsule
gland as long as albumen gland. Genital aperture a subterminal
slit with very short vestibule. Coiled oviduct a weak horizontal
kink followed by broad, horizontal loop slightly behind pallial
wall. Oviduct and bursal duct join just behind pallial wall.
Bursa copulatrix sub-globular, short (30%), narrow (37%),
with 33%-50% of length posterior to gland Bursal duct
medium width, about as long as bursa copulatrix, shallowly
embedded in albumen gland proximally. Seminal receptacle