title: Redescription of Marstonia comalensis (Pilsbry & Ferriss, 1906), a poorly known and possibly threatened freshwater gastropod from the Edwards Plateau region (Texas).
abstract: Marstonia comalensis, a poorly known nymphophiline gastropod (originally described from Comal Creek, Texas) that has often been confused with Cincinnatia integra, is re-described and the generic placement of this species, which was recently allocated to Marstonia based on unpublished evidence, is confirmed by anatomical study. Marstonia comalensis is a large congener having an ovate-conic, openly umbilicate shell and penis having a short filament and oblique, squarish lobe bearing a narrow gland along its distal edge. It is well differentiated morphologically from congeners having similar shells and penes and is also genetically divergent relative to those congeners that have been sequenced (mtCOI divergence 3.0-8.5%). A Bayesian analysis of a small COI dataset resolved Marstonia comalensis in a poorly supported sub-clade together with Marstonia hershleri, Marstonia lustrica and Marstonia pachyta. The predominantly new records presented herein indicate that Marstonia comalensis was historically distributed in the upper portions of the Brazos, Colorado, Guadalupe and Nueces River basins, south-central Texas. The species has been live collected at only 12 localities and only two of these have been re-visited since 1993. These data suggest that the conservation status of this snail, which has a critically imperiled (G1) NatureServe ranking and was recently proposed for federal listing, needs to be re-assessed.
authors: Department of Invertebrate Zoology, Smithsonian Institution, P.O. Box 37012, Washington, D.C. 20013-7012, USA.
authors: Robert
authors: R
authors: Hershler
authors: Hsiu-Ping
authors: HP
authors: Liu
references: Mol Phylogenet Evol. 2001 Oct;21(1):17-25
references: 11603933
references: Bioinformatics. 2003 Aug 12;19(12):1572-4
references: 12912839
references: Mol Biol Evol. 2007 Aug;24(8):1596-9
references: 17488738