Tryonia taylori, 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 : 18-19

publication ID	https://doi.org/ 10.5281/zenodo.278442
DOI	https://doi.org/10.5281/zenodo.5629203
persistent identifier	https://treatment.plazi.org/id/03E687C5-BF66-831C-FF2E-1595FA9D1A78
treatment provided by	Plazi
scientific name	Tryonia taylori
status	sp. nov.

Treatment

Tryonia taylori sp. nov.

( Figs 5 View FIGURE 5 G–H, 9A–D, G–I, L–N)

Types: Holotype, USNM 873254, ouflow of Ojo Caliente at Rancho Ojo Caliente, south of Highway 10, Chihuahua, 29º54'10.2" N, 107º15'27.1" W, leg. J.J.L. et al., 27/viii/1971. Paratypes (from same lot), USNM 1153678.

Etymology. A patronym honoring the late Dwight W. Taylor for his pioneering taxonomic studies of Tryonia ( Taylor 1987) .

Referred material. CHIHUAHUA. USNM 873251, topotypes, leg. J.J.L. et al., 27/viii/1971. USNM 874047, topotypes, leg. J.J.L. and P. Hines, 18/ix/1990. USNM 1135493, topotypes, R.H. and J.J.L., 7/xii/1998. USNM 873283, El Ojo de Servin, 5.6 km west of Rancho Ojo Caliente, 0.2 km north of Highway 10, 29º54'17.2" N, 107º18'27.2" W, leg. J.J.L., 14/iv/1973. USNM 873252, USNM 873297, ibid, leg. J.J.L. et al., 27/viii/1971. USNM 874050, ibid., leg. J.J.L., 18/ix/1990. USNM 892118, ibid., leg. R.H. and J.J.L., 7/xii/1998. UTEP 978, ibid., leg. A. Metcalf and D.W. Taylor, 4/ix/1969. BellMNH 21172, BellMNH 21173, ibid., leg. D.W. Taylor and A. Metcalf, 4/ix/1969.

Diagnosis. Shell medium- to large-sized, conic or elongate-conic; penis having two distal papillae on inner edge and sometimes two–four basal papillae on inner edge and/or dorsal surface. Differentiated from closely similar T. molinae above.

Description. Shell ( Fig. 9 View FIGURE 9 A–D) up to 6.7 mm tall, whorls ca. 5.50–8.75, spire height 135–220% width of shell, male shells smaller than those of females. Teleoconch whorls usually weak to medium convex, rarely high convex, evenly rounded or weakly shouldered with impressed or adpressed sutures. Aperture weakly or sharply angled adapically, parietal lip usually complete, usually adnate, rarely slightly disjunct, umbilicus narrow or absent. Outer lip sometimes slightly thickened adapically, orthocline or weakly prosocline. Sculpture of strong growth lines and weak spiral threads. Periostracum tan.

Shell measurements (mean in parentheses): height 3.42–4.25 mm (3.74), width 1.54–1.84 mm (1.67), body whorl height 1.93–2.22 mm (2.09), body whorl width 1.46–1.73 mm (1.59), aperture height 1.03–1.33 mm (1.22), aperture width 0.89–1.09 mm (1.00), total number of whorls 5.50–6.50 (6.00) (USNM 1153678, n = 15).

Measurements of holotype: height 3.74 mm, width 1.59 mm, body whorl height 2.16 mm, body whorl width 1.55 mm, aperture height 1.24 mm, aperture width 1.01 mm, 6.0 whorls.

Outer side of operculum smooth ( Fig. 9 View FIGURE 9 G) or with edges of last 0.5 whorl frilled; inner side of operculum nearly smooth ( Fig 10 View FIGURE 10 H) or with edges of muscle attachment scar thickened ( Fig. 9 View FIGURE 9 I). Radula ( Fig. 9 View FIGURE 9 L-N): dorsal edge of central radular teeth concave, basal tongue rounded, median cusps elongate, distally pointed, lateral cusps four–seven, basal cusps one–three (innermost larger) ( Fig. 9 View FIGURE 9 M). Lateral teeth having two–five cusps on inner and three–seven cusps on outer side, length of outer wing 160–200% width of cutting edge, central cusp pointed ( Fig. 9 View FIGURE 9 N) or jagged-edged. Inner marginal teeth with 19–32 cusps, outer marginal teeth with 25–49 cusps. Radula data are from USNM 873283, USNM 1153678.

Animal darkly pigmented. Penis ( Fig. 5 View FIGURE 5 G–H) usually having two distal papillae on inner edge (46 of 56 specimens from two samples), eight specimens differed in having three distal papillae and two differed in having a single distal papilla. Ojo Caliente specimens usually lacking basal penial papillae (25 of 27 specimens), one specimen differed in having a basal papilla both on the inner and outer edges, one specimen differed in having two dorsally positioned basal papillae. Ojo de Servin specimens usually having two–three dorsally positioned basal penial papillae (27 of 29 specimens) and sometimes also having a basal papilla on the inner edge (12 of 29 specimens); one specimen had four dorsally positioned papillae and one specimen lacked basal papillae. Distal bulb of penis evenly rounded or expanded laterally on inner side, black; stylet small. Penial duct nearly straight to strongly undulating along most of length. Penial data are from USNM 873251, USNM 873252.

Distribution and habitat. Narrowly endemic in the Río Santa Maria drainage ( Fig. 1 View FIGURE 1 , locality 7). The type locality (Ojo Caliente) is a thermal spring (36–39°C) that is enclosed in a bath house ( Fig. 6 View FIGURE 6 H). Tryonia taylori was found on mud, rocks and aquatic vegetation in the outflow 5–6 meters below the bath house. We did not discern a marked change in this spring from 1971–1998. The second locality, El Ojo de Servin, is a warm spring complex (23–26°C) about 5 km west of Ojo Caliente. Tryonia taylori is extremely abundant on algae and Chara in the headspring area and somewhat less common in shallow portions of the spring runs on mud. This formerly lush cienega (as observed in 1971, Fig. 6 View FIGURE 6 I) is now severely overgrazed ( Fig. 6 View FIGURE 6 J).

Remarks. The two populations of T. taylori formed a strongly supported clade in the Bayesian tree ( Fig. 2 View FIGURE 2 ). These populations differ in shell size (3.7 vs. 5.8 mm mean shell height, t-test, t = -13.811, df = 18.6, P <0.01, n=13 for the El Ojo de Servin sample), teleoconch whorl convexity, number of cusps on the outer marginal teeth, and the number and arrangement of basal papillae on the penis. However, they do not form reciprocally monophyletic clades in the Bayesian tree and their sequence divergence ranged from 0.3 to 1.7% ( Table 2 View TABLE 2 ). We treat these morphologically distinctive populations as conspecific based on the evolutionary lineage concept used herein.

References

Figures

FIGURE 6. Photographs of habitats of species treated in this paper. A. Ojo Vareleño, Chihuahua, type locality of T. peregrina sp. nov. (photograph taken on 16 / ix / 1990). B. Main spring in Yepomera, Chihuahua, T. peregrina habitat (18 / ix / 1990). C. Springs northeast of Ignacio Zaragoza, Chihuaua, type locality of T. zaragozae sp. nov. (8 / xii / 1998). D. Western-most head spring, Ojos de Arrey, Chihuahua, type locality of T. angosturae sp. nov. and T. ovata sp. nov. (7 / xii / 1998). E. Spring in northern part of El Molino, Chihuahua, type locality of T. molinae sp. nov. (26 / iv / 2010). F. Ojo del Apache, Chihuahua, type locality of T. contrerasi sp. nov. (14 / xii / 1998). G. Ojo Carbonero, Chihuahua, T. contrerasi habitat (2 / iv / 1991). H. Outflow of Ojo Caliente, Chihuahua, type locality of T. taylori sp. nov. (7 / xii / 1998). I – J. El Ojo de Servin, Chihuahua, T. taylori habitat (27 - viii- 1971, 7 / xii / 1998, respectively). K. Seeps in La Cienega, Texas, type locality of T. metcalfi sp. nov. (6 / xii / 2001). L – M. Balneario de San Diego de Alcala, Chihuahua, type locality of T. chuviscarae sp. nov. and T. minckleyi sp. nov. (4 / xii / 2001). N. Springs southeast of Julimes, Chihuahua, type locality of T. julimesensis sp. nov. (5 / iv / 1991). O. El Ojito (outflow), southwest of Talamantes, Chihuahua, type locality of T. allendae sp. nov. (10 / xii / 1998). P. Caroline Spring, Oasis Ranch, Texas, type locality of T. oasiensis sp. nov. (30 / iii / 2009). Q. Spring in Nombre de Dios, Durango, T. seemani habitat (2 / ix / 1971). R. Spring in Amado Nervo, Durango, T. seemani habitat (7 / iv / 1991).