Boletín de la Sociedad Geológica Mexicana
Volumen 69, núm. 1, 2011, p. 199 ‒ 208
Two new subfossil species of springsnails (Hydrobiidae: Pyrgulopsis) from North Mexico and their relation with extant species from Cuatrociénegas
Alexander Czaja1, José Luis Estrada-Rodríguez1,*, Ulises Romero-Méndez1, Anselmo Orona-Espino1
1Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango, 35010 Gómez Palacio, Durango, México.
We describe two new species of the genus Pyrgulopsis Call and Pilsbry from subfossil spring deposits of Viesca, Coahuila, in the northern part of Mexico. The first species, P. paleominckleyi sp. nov., has trochiform shells with flat whorls and bulbous shoulders. Extant endemic species Pyrgulopsis minckleyi (Taylor) displayssimilar shell features — this species was originally described as Nymphophilus minckleyi Taylor from the spring complex of the Cuatrociénegas valley, Coahuila. Some specimens of P. paleominckleyi sp. nov. show wing-like shoulders that have never been observed among fossil or extant members of the genus. In addition, shells of the second new species from Viesca, P. paleoacarinatus are similar to P. acarinatus, which is other endemic Pyrgulopsisspecies from Cuatrociénegas. We suppose that both sub-fossil springsnails of Viesca are sister species or, likely, direct precursors of the two extant endemic springsnails from Cuatrociénegas valley.
Keywords: Pyrgulopsis, new species, sub-fossil, North Mexico, Viesca, Cuatrociénegas.