New species and records of phreatic snails (Caenogastropoda:Cochliopidae) from the Holocene of Coahuila, Mexico

This paper describes 2 new species of phreatic gastropods from the Holocene deposits of Parras and Viesca, Coahuila, northern Mexico. Both new fossil species belong to genera that today are known living only from the Cuatro Ciénegas basin, Coahuila, Mexico, one of the hotspots of extant freshwater gastropod diversity on the North American continent, frequently called the “Mexican Galapagos”. Paludiscala thompsoni n. sp. was found in spring-deposited sediments at the outlet of caves near Viesca, Coahuila, and is the first record of fossil shells of this genus. Our second new species, Coahuilix parrasense n. sp., was collected in sediments of a dry channel near the town El Molino, Parras de la Fuente, Coahuila, and its shell morphology has affinities with that of extant endemic cave snails from Cuatro Ciénegas. Additionally, we present a new record from Parras de la Fuente of Phreatoceras taylori (Hershler & Longley, 1987), previously known only from 2 sites in south-central Texas and Cuatro Ciénegas.