Tryonia minckleyi, Hershler, Robert, Liu, Hsiu-Ping & Landye, Jerry, 2011

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, Zootaxa 3001, pp. 1-32 : 23-24

publication ID	https://doi.org/ 10.5281/zenodo.278442
DOI	https://doi.org/10.5281/zenodo.5629209
persistent identifier	https://treatment.plazi.org/id/03E687C5-BF61-8319-FF2E-14C9FA901B10
treatment provided by	Plazi
scientific name	Tryonia minckleyi
status	sp. nov.

Treatment

Tryonia minckleyi new species

( Figs 5 View FIGURE 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 View FIGURE 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 View FIGURE 10 H–I). Radula ( Fig. 10 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 2 ).