Phreatoviesca Czaja & Gladstone, 2021

Czaja 1, Alexander, Gladstone 2, Nicholas S., Becerra-Lopez 1, Jorge Luis, Estrada-Rodriguez 1, Jose Luis, SaenzMata 1, Jorge & Hernandez-Teran 3, Fernando, 2021, A remarkable new genus and species of subterranean freshwater snail from a recently dried-up spring of Viesca, Coahuila, Northern Mexico, Subterranean Biology 39, pp. 129-141 : 129

Phreatoviesca Czaja & Gladstone gen. nov.

Type species.

Phreatoviesca spinosa by present designation.

Diagnosis.

Shell small, conical in form, protoconch sculptured with coarsely honeycomb-like pits, teleoconch with curved ribs which are at the carina modified into regularly spaced shovel-shaped spines (Figs 14 , 24 ), body whorl always open-coiled, some specimens with a corkscrew morphology, apertures large, ovate, rarely rounded, often trumpet-like.

Differential diagnosis.

The characteristic combination of three aforementioned shell features (open coiling of the last whorl, shovel-shaped spines, and protoconch with coarsely honeycomb-like pits) separate the new genus clearly from shells of all other subterranean (and epigean) genera. Some members of Phreatodrobia Hershler & Longley 1986 and Paludiscala Taylor 1966, genera which include exclusively subterranean species, also have conical shells, but these are not uncoiled (except the slightly uncoiled Phreatodrobia nugax (Pilsbry & Ferriss, 1906) to this extent do not possess prominent spine ornamentations.

Etymology.

The name is derived from Greek phreato = groundwater environment, and Viesca (referring to the town of Viesca where the shells were found).

Figures

Figures 14 - 17. SEM images of Phreatoviesca spinosa gen. nov. et sp. nov. 14 specimen with strong spines, UJMC 506 15 specimen with ribs, UJMC 507 16 specimen with smooth whorls, UJMC 508 17 specimen with smooth whorls, UJMC 509. Scale bar: 1 mm.

Figures 18 - 24. SEM images of Phreatoviesca spinosa gen. nov. et sp. nov. 18 shell apex with protoconch, UJMC 508 19 paratype 3, shell apex with protoconch, UJMC 503 20 shell apex with protoconch, UJMC 510 21 paratype 1, apex with protoconch, UJMC 501 22 smooth specimen with body whorl shows irregular, strong marked growth lines, UJMC 508 23 paratype 1, body whorl shows irregular, strong marked growth lines, UJMC 501 24 paratype 2, body whorl shows regularly spaced shovel-shaped spines, UJMC 502.