Fontigens morrisoni

Fontigens morrisoni

Fontigens aldrichi.—Hubricht, 1976:87.—Holsinger and Culver, 1988:22. [In part-]

Fontigens orolibas(?).—Holsinger, 1982:98.

DIAGNOSIS.—A small-sized species with stout, ovate-conic shell. Penis with two accessory lobes containing tubular and bulbous glands.

DESCRIPTION.—Shell (Figure 21, Table 5) 1.5–2.5 mm tall; height/width, 125%–160%. Whorls, 3.25–4.0, well rounded, often with narrow adapical shoulders. Spire convex. Aperture broadly ovate, only moderately angled above. Inner lip slightly thickened and reflected, usually adnate to small portion of body whorl. Umbilicus usually open. Apex (Figure 22c) slightly depressed to slightly protruding; protoconch with numerous well incised striae.

Eyespots pigmented. Head/foot pale or covered with light, brown pigment Dorsal surface of visceral coil brown-black, digestive gland especially darkened.

Radular formula (Figure 22a,b,d–f): 7-1-7/1-1, 2(3)-1-3(4), 20-22, 17-24. Central cusp of lateral tooth enlarged, hoe-like.

Ctenidial filaments, ~17; osphradium slightly elongate compared to that of other congeners. Testis, 1.0 whorl. Penis (Figure 22g) moderate-sized. Penial filament broad, distal portion with pronounced sub-terminal bulge. Proximal lobe short, stout. Ovary, 0.25 whorl. Capsule gland slightly longer than albumen gland. Ventral channel very broad (width almost that of capsule gland) along entire length. Bursa copulatrix gourd-shaped; narrow anterior portion overlapping half of albumen gland length. Duct of bursa originates from near mid-point of structure and extends over much of albumen gland. Oviduct coil enlarged.

ETYMOLOGY.—Named after the late Dr. J.P.E. Morrison of the National Museum of Natural History, who had a deep interest in Fontigens and whose extensive collection of these snails was invaluable to the present study.

TYPE LOCALITY.—A small spring-fed brook SW of Mustoe (along HW 220), Highland Co., Virginia. Holotype, USNM 860466; paratypes, USNM 860467.

DISTRIBUTION AND HABITAT.—Known from two springs and two caves in Upper James River basin, Bath and Highland counties, Virginia (Figure 23).

MATERIAL EXAMINED.—VIRGINIA. Batth County: Blowing Cave, 1.7 km NW of Millboro Springs (LH coll.); Butler Cave, 1.6 km N of Burnsville, LH 38731. Highland County: Spring, 1.1 km SW of Mustoe, LH 40580; Spring, 2.1 km N of Mustoe, LH 40581.