Pyrgulopsis lustrica (Pilsbry 1890)

Pyrgulopsis lustrica (Pilsbry, 1890)

Amnicola lustrica Pilsbry, 1890:53.—Baker, 1964:174.

Amnicola lacustris Pilsbry, 1891a:iii [of Index; nomen nudum, probably misspelling of above].

Amnicola (Marstonia) lustrica.—Baker, 1926:195.—Berry, 1943:29, fig. 3; pl. 1: figs. 4–6; pl. 3: fig. 3; pl. 5: fig. 6.—Robertson and Blakeslee, 1948:84, pl. X: fig. 11.

Lyogyrus (Marstonia) lustrica.—Thiele, 1928:378.

Marstonia lustrica.—Thompson, 1977:124, figs. 2, 4d, 5, 16.—Turgeon et al., 1988:61.

Pyrgulopsis lustrica.—Hershler and Thompson, 1987:29, fig. 5.

Amnicola lustrica gelida Baker, 1921:22.

Marstonia gelida.—Clarke, 1973:247, pl. 21: figs. 7, 8.—Nielsen et al., 1987:1480.

Amnicola lustrica decepta Baker, 1928:108, fig. 45 [in part].

Marstonia decepta.—Clarke, 1973:244, pl. 21: fig. 6.

Amnicola lustrica perlustrica Baker, 1928:109, pl. VI: figs. 15, 45 [in part].

Amnicola oneida Pilsbry, 1917:46.—Baker, 1964:175.—Richardson et al., 1991:64.

DIAGNOSIS.—Shell ovate- to narrowly-conic, medium to large-sized, umbilicate. Penial filament short, stubby; lobe short, oblique. Penial ornament an elongate, usually transverse terminal gland.

DESCRIPTION.—Shell (Figure 29a) ovate- to narrowly-conic; height, 3–5 mm; whorls, 4.5–6.0. Early protoconch strongly punctate. Teleoconch whorls moderate to highly convex; sculpture of weak growth lines. Aperture ovate, small, adnate or slightly separated from body whorl. Inner lip complete, sometimes slightly thickened; columellar lip sometimes slightly reflected. Outer lip usually thin, orthocline to slightly prosocline. Umbilicus open. Periostracum olive-gray.

Operculum (Figure 29b,c) ovate, amber, slightly indented along outer edge; nucleus slightly eccentric; dorsal surface weakly frilled. Attachment scar margin slightly thickened along outer edge and between nucleus and inner edge; callus weak.

Central radular tooth (Figure 41f) with weakly indented dorsal edge; lateral cusps, 3–5; central cusp rounded, slightly broader and considerably longer than laterals; basal cusps, 1 (sometimes with weak suggestion of outer cusp), medium-sized, curved, with moderate dorsal support. Basal process broad; basal sockets deep. Lateral margins thickened; neck weak-absent.

Head-foot entirely pale or with light brown tentacles, light-dark snout, light-moderate brown foot (especially anterior and posterior edges). Pallial roof uniform brown-black or pale except for strong black bands along edges of ctenidium and (sometimes) along dorsal edge of glandular gonoduct (Figure 2e). Visceral coil light to dark.

Ctenidial filaments, 25, medium height and width. Osphradium centered from middle to within posterior half of ctenidial axis. Kidney with moderate-large bulge into pallial cavity. Hypobranchial gland well-developed, often with thickened amber portion near kidney. Stomach with small to medium-sized caecum.

Testis, 1.5–2.0 whorls, overlapping stomach to edge of style sac. Prostate gland broad, with small-large pallial section (15%–25%); pallial vas deferens with proximal loop. Penis (Figure 52f) medium-sized; filament short, stubby, without taper; lobe shorter than filament, oblique. Terminal gland elongate, often transverse, borne along distal edge (both surfaces). Filament light to darkly pigmented internally.

Female genitalia are shown in Figure 5c. Ovary, 0.5–1.0 whorl, overlapping posterior stomach chamber. Pallial albumen gland large (35%). Capsule gland longer than albumen gland, thickened. Genital aperture a sub-terminal slit with vestibule. Coiled oviduct a slight anterior bend followed by tall, narrow, vertical loop just behind pallial wall. Oviduct and bursal duct join well anterior to oviduct coil in front of pallial wall. Bursa copulatrix ovoid, medium length, broad (65%), with about half of length posterior to albumen gland. Bursal duct medium width, deeply embedded in albumen gland, about twice as long as bursa copulatrix. Seminal receptacle pouch-like, short, with very short duct, positioned lateral to proximal bursal duct along ventral edge of albumen gland.

TYPE LOCALITY.—Pyrgulopsis lustrica: “New York to Illinois and Minnesota” (Pilsbry, 1890). The type is labeled Little Lakes (Wayne County), New York. Holotype, ANSP 284061; paratypes, ANSP 396955. Pyrgulopsis oneida: Lower South Bay, Oneida Lake, New York. Lectotype (Baker, 1964:175), ANSP 283876; paralectotypes, ANSP 317030, ANSP 396989. Pyrgulopsis gelida: Pleistocene, near Morris, Grundy County, Illinois. Holotype, UIMNH P926 (possibly lost); paratypes, UIMNH P927. Pyrgulopsis decepta: Silver Lake, Waukesha County, Wisconsin. Holotype, UIMNH Z22501; paratypes, UIMNH Z22502. Pyrgulopsis perlustrica: Michigan shore east of Sturgeon Bay, Door County, Wisconsin. Holotype, UIMNH Z18365a (presumably lost; Franzen, 1956:22); paratypes, UIMNH Z18365a.

DISTRIBUTION.—Great Lakes region, upper Mississippi River drainage and (rarely) Atlantic Coastal drainage, northeastern United States and southeastern Canada (Thompson, 1977, fig. 15).

MATERIAL EXAMINED.—FSM 22227, Midland, Clarke County, Ohio.