Tryonia minckleyi Hershler, Liu & Landye, 2011, new species
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 minckleyi

description: Tryonia minckleyi new species
(Figs 5 K, 10D–E, H–I, M– O)
Types. Holotype, USNM 1001751, Balneario de San Diego de Alcala, Chihuahua, 28º35'17.6" N, 105º32'50.8" W, leg. R.H. and J.J.L., 4/xii/2001. Paratypes (from same lot), USNM 1001755, USNM 1153673.
Etymology. A patronym honoring the late Wendell L. Minckley for his remarkable record of research on aquatic biota of the Chihuahuan Desert (Collins et al. 2002) and for leading the collecting expeditions that resulted in the discovery of this (and many other) species.
Referred material. CHIHUAHUA. USNM 873200, USNM 905268, USNM 905269, topotypes, J.J.L. et al., 29/viii/1971.
Diagnosis. Shell small, ovate-conic or conic; penis having two distal papillae on the inner edge and one–two basal papillae on the outer edge. Contrasted with syntopic T. chuviscarae above. Differs from T. julimesensis (described next), which is also distributed in the Río Conchos basin, in having basal penial papillae. Readily distinguished from conchologically similar T. allendae (described below), which is also distributed in the Río Conchos basin, by its more rounded shell whorls, more elongate cusps on the lateral radular teeth, larger penial stylet, weakly undulating penial duct, and smaller lateral expansion of the terminal bulb of the penis.
Description. Shell (Fig. 10 D–E) up to 2.8 mm tall, large females having 4.75–5.50 whorls, spire height 120–140% width of shell, male shells smaller than those of females. Teleoconch whorls high convex, shouldered, sutures impressed. Aperture rounded adapically, parietal lip complete, usually adnate, rarely slightly disjunct, umbilicus narrow or absent. Outer lip thin, orthocline. Sculpture of strong growth lines, weak spiral thread also sometimes present. Periostracum light tan.
Shell measurements (mean in parentheses): height 2.25–2.70 mm (2.48), width 1.17–1.31 mm (1.24), body whorl height 1.44–1.62 mm (1.53), body whorl width 1.06–1.24 mm (1.16), aperture height 0.81–0.95 mm (0.87), aperture width 0.70–0.78 mm (0.74), total number of whorls 4.75–5.25 (4.93) (USNM 1153673, n = 15).
Measurements of holotype: height 2.69 mm, width 1.28 mm, body whorl height 1.62 mm, body whorl width 1.19 mm, aperture height 0.94 mm, aperture width 0.74 mm, 5.0 whorls.
Inner and outer sides of operculum smooth (Fig. 10 H–I). Radula (Fig. 10 M-O): dorsal edge of central radular teeth weakly concave, basal tongue rounded, median cusps distally pointed, parallel-sided proximally, lateral cusps four–five, basal cusps two (equal-sized or innermost larger), small (Fig. 10 N). Lateral teeth having two–three cusps on inner and four–five cusps on outer sides, length of outer wing about 180% width of cutting edge, central cusp pointed, curved (Fig. 10 O). Inner marginal teeth having 19–30 cusps, outer marginal teeth having 25–31 cusps. Radula data are from USNM 1153673.
Animal darkly pigmented. Penis (Fig. 5 K) usually having two distal papillae on the inner edge and one–two basal papillae on the outer edge (19 of 30 specimens). Two specimens differed in having a single distal papilla on the inner edge, one specimen differed in having three distal papillae on the inner edge, two specimens lacked a papilla on the outer edge, two specimens had three basal papillae on the outer edge, one specimen had five basal papillae on the outer edge, and one specimen had two distal and four basal papillae on the outer edge. Distal bulb of penis weakly expanded laterally on inner side, black; stylet large. Penial duct straight or weakly undulating along most of length. Penial data are from USNM 1153673.
Distribution and habitat. Endemic to the type locality in the Río Conchos basin (Fig. 1, locality 9). Habitat as for T. chuviscarae (see above).
Remarks. Tryonia minckleyi was delineated as a well supported lineage in the Bayesian tree (Fig. 2).
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 23-24, DOI: 10.5281/zenodo.278442