Some Mexican Land Snails of the Genera Coelostemma and Metastoma (Urocoptidae)

Abstract

The following new taxa are described: C. leucostoma n. sp., C. bembix n. sp., C. eclipes n. sp., C. anaclasta n. sp., C. richardi n. sp., C. notogastor n. sp., C. astraxis n. sp., C. fornax n. sp. and C. fornax ix n. ssp. Two new subgenera are also proposed: Crycoryne n. subg. (type species: C. astraxis) and Styloptyx n. subg. (type species: C. fornax): C. antricola Bartsch is reduced to subspecific status as C. bourgeoisana antricola C. amplazis Pilsbry, type species of the subgenus Apertaxis, is synonymized with C. coahuilensis (Bartsch). Metastoma is elevated from a subgenus of Holospira to generic status and is closely related to Coelostemma.  Aspects of the embryonic sculpture are determined for C. elizabethae (Pilsbry), C. b. bourgeoisana Bartsch, C. b. antricola Bartsch, C. iqualaensis (Bartsch), C. hazelae Pilsbry, C. fusca (Martens), C. coahuilensis (Bartsch) and Metastoma roemeri (Pfeiffer). These are features omitted in earlier descriptions of these species.