Pyrgulopsis arizonae (D. W. Taylor 1987)

Pyrgulopsis arizonae (Taylor, 1987)

Apachecoccus arizonae Taylor, 1987:32, fig. 15.—USDI, 1991b:58818.

Pyrgulopsis sancarlosensis Hershler in Hershler and Landye, 1988:35, figs. 13e, 26e, 31a-g, 32, 33.

DIAGNOSIS.—Shell globose to elongate conic, small to medium-sized, umbilicate. Penial filament medium length, broad; lobe elongate. Penial ornament a large, superficial ventral gland often accompanied by a similar dorsal gland. Seminal receptacle absent.

DESCRIPTION.—Shell (Figure 8d) globose to elongate conic; height, 1.1–2.4 mm; whorls, 3–4 whorls. Early protoconch moderately punctate, otherwise smooth except for a few adapical spiral lines on later portion. Teleoconch whorls moderately convex, strongly shouldered; sculpture of faint growth lines. Aperture generally ovate, medium to large-sized, usually widely separated from body whorl. Inner lip complete, moderately thick; columellar lip moderately reflected. Outer lip orthocline to slightly prosocline. Umbilicus narrow to broadly open. Periostracum light brown. Operculum (Figure 8e,f) ovate, pale to light yellow; nucleus highly eccentric; dorsal surface frilled. Attachment scar margin broadly thickened between nucleus and inner edge, otherwise faint; callus small.

Central radular tooth (Figure 33d) with strongly indented dorsal edge; lateral cusps, 3–5; central cusp pointed, narrow, considerably longer than laterals; basal cusps, 1, medium length, with very weak dorsal support. Basal process moderately broad; basal sockets deep. Lateral margins slightly thickened; neck pronounced.

Snout pale to dark brown. Cephalic tentacles usually pale, sometimes light brown. Neck, foot, opercular lobe usually very light, but varying to dark brown. Pallial roof, visceral coil usually dark brown-black, but sometimes quite light.

Ctenidial filaments, 15–18, medium height and width. Osphradium near centrally positioned along ctenidial axis. Kidney opening white. Stomach caecum very narrow, hemispherical.

Testis, 1 whorl, overlapping posterior stomach. Prostate gland with short pallial section; pallial vas deferens proximally kinked. Penis (Figure 43d) very large, with filament extending well beyond edge of mantle; filament broad, longer than base, tapering distally; lobe medium length, with broad distal edge. Dorsal lobe often bearing large, oval, superficial gland centrally. Ventral gland similar in size and shape, borne on central portion of ventral lobe, rarely accompanied by smaller adjacent gland. Penis unpigmented or with dark internal pigment in filament.

Female genitalia shown in Figure 4b. Ovary, 1 whorl, overlapping stomach to edge of style sac. Pallial albumen gland extremely short or absent. Capsule and albumen glands about equal in length; capsule gland very weakly differentiated into two tissue sections. Genital aperture a short terminal slit without vestibule. Coiled oviduct a weak proximal oblique kink followed by thickened, broad, horizontal loop filling half or more of albumen gland length. Oviduct and bursal duct join beneath central portion of loop well posterior to pallial wall. Bursa copulatrix pyriform, posterior end weakly angled, long (66%), almost as broad as albumen gland (73%), with about 85% of length posterior to gland. Bursal duct narrow, slightly shorter than bursa copulatrix. Seminal receptacle absent.

TYPE LOCALITY.—Pyrgulopsis arizonae: Unnamed spring on north side of Gila River about 2 mi (3.2 km) north of Bylas (in T 3S, R 22E, 25,000 ft (7.6 km) west and 15,500 ft (4.7 km) north of the township line, Graham County, Arizona). Holotype, LACM 2203; paratypes, UTEP 10050, ANSP 376020, FSM 160939, USNM 854090. Pyrgulopsis sancarlosensis: Springs west of Tom Niece Springs, Graham County, Arizona (T 4S, R 23E, 0.6 km S, 0.4 km W of SE1/4 sec. 21). Holotype, USNM 859051; paratypes, USNM 859052.

DISTRIBUTION.—Upper Gila River drainage, southeastern Arizona.

MATERIAL EXAMINED.—USNM 847226 (topotypes, sancarlosensis).

Pyrgulopsis arizonae, commonly known as the Apache springsnail, is a species of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the family Hydrobiidae.

This species' natural habitat is springs. It is endemic to an unnamed spring on north side of Gila River about 2 miles (3.2 km) north of Bylas, Arizona, United States.