Tryonia angosturae Hershler, Liu & Landye, 2011, sp. nov.
Creators: name: Hershler, Robert
name: Liu, Hsiu-Ping
name: Landye, Jerry
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Hydrobiidae
Tryonia
Tryonia angosturae

description: Tryonia angosturae sp. nov.
(Figs 5 D, 7C–E, H–I, M– O)
Tryonia n. sp. 3.— Hershler et al. 2005: 1757 (COI sequence).
Types. Holotype, USNM 873259, Ojos de Arrey, western-most head spring, south of Galeana, Chihuahua, 30º3'28.3" N, 107º35'26.3" W, leg. J.J.L. et al., 25/viii/1971. Paratypes (from same lot), USNM 873261, USNM 873285, USNM 905267, USNM 1153668.
Etymology. The species name is a geographic epithet referring to a nearby village, La Angostura.
Referred material. CHIHUAHUA. USNM 873268, topotypes, leg. J.J.L., 14/iv/1973. USNM 874250, USNM 874174, ibid., leg. J.J.L. and P. Hines, 16/ix/1990. USNM 854943, ibid., leg. R.H. and J.J.L., 7/xii/1998. USNM 873293, canal outflow from Ojos de Arrey at Hwy 10, 30º4'11" N, 107º36'15" W, leg. J.J.L., 25/viii/1971. BellMNH 21128, Oja del Rey (sic), leg. D.W. Taylor, 3/ix/1969. BellMNH 21175, east Ojo del Rey (sic), northwest end of Cerro Angostura, leg. D.W. Taylor and A. Metcalf, 3/ix/1969. BellMNH 21174, Ojo del Torreon, northwest end of Cerro Angostura, leg. D.W. Taylor and A. Metcalf, 3/ix/1969.
Diagnosis. Shell medium-sized, conic; penis having two distal papillae on the inner edge and a basal papilla on the outer edge. Contrasted with T. ovata above. Differentiated from other Río Santa Maria basin congeners by having a basal papilla on the outer edge of the penis.
Description. Shell (Fig. 7 C–E) up to 4.9 mm tall, large females having 5.0–8.0 whorls, spire height 85–110% width of shell, male shells smaller than those of females. Teleoconch whorls weak to medium convex, evenly rounded, sutures impressed. Aperture weakly angled adapically, parietal lip usually complete, usually adnate, rarely very slightly disjunct, umbilicus absent. Outer lip thin, weakly prosocline. Sculpture of strong growth lines. Periostracum brown or tan.
Shell measurements (mean in parentheses): height 2.69–3.36 mm (3.01), width 1.16–1.38 mm (1.25), body whorl height 1.41–1.68 mm (1.55), body whorl width 1.13–1.45 mm (1.26), aperture height 0.76–0.89 mm (0.82), aperture width 0.65–0.82 mm (0.72), total number of whorls 5.25–6.75 (5.92) (USNM 1153668, n = 15).
Measurements of holotype: height 2.76 mm, width 1.25 mm, body whorl height 1.49 mm, body whorl width 1.19 mm, aperture height 0.82 mm, aperture width 0.68 mm, 5.75 whorls.
Edges of last 0.5 operculum whorl sometimes weakly frilled on outer side (Fig. 7 H); inner side of operculum smooth (Fig. 7 I). Radula (Fig. 7 M– O): dorsal edge of central radular teeth weakly convex, basal tongue rounded Vshaped, median cusps distally pointed, parallel-sided proximally, lateral cusps four–six, basal cusps one–three (innermost larger) (Fig. 7 N). Lateral teeth having two–three cusps on inner and three–four cusps on outer sides, length of outer wing about 180% width of cutting edge, central cusp pointed (Fig. 7 O). Inner marginal teeth having 14–19 cusps, outer marginal teeth having 27–38 cusps. Radula data are from USNM 1153668.
Animal darkly pigmented. Penis (Fig. 5 D) having two distal papillae on the inner edge and a basal papilla on the outer edge (all 36 specimens from three samples). Distal bulb of penis expanded laterally on inner side, dark brown; stylet small. Penial duct undulating along most of length. Penial data are from USNM 873293, USNM 874174, USNM 905267.
Distribution and habitat. Tryonia angostura is endemic to the type locality area in the Río Santa Maria basin (Fig. 1, locality 5). Habitat as for T. ovata (described above). Tryonia angostura has also been collected in the main spring canal (from Ojos de Arrey) at the Highway 10 crossing.
description: Published as part of Hershler, Robert, Liu, Hsiu-Ping & Landye, Jerry, 2011, New species and records of springsnails (Caenogastropoda: Cochliopidae: Tryonia) from the Chihuahuan Desert (Mexico and United States), an imperiled biodiversity hotspot, pp. 1-32 in Zootaxa 3001 on pages 13-15, DOI: 10.5281/zenodo.278442