Placas columnares de crinoideos de la Formación Las Delicias, Pérmico inferior y medio de Coahuila, México

Abstract

Thirteen parataxa of crinoid plates from two localities of the lower-middle Permian of the Las Delicias Formation are described. Both zones are situated in Sierra de las Delicias, to southwestern Coahuila state. The parataxa Pentagonopternix coahuilensis n. sp., Cyclocaudex typicus, C. insaturatus, C. cf. insaturatus, Cyclocaudex sp., Floricyclus diminuta n. sp., Floricyclus sp. Preptopremnum rugosum, P. laeve, Preptopremnum sp., Heterostelechus keithi, Cyclocaudiculus regularis and Epicrinus torreonense new genus and species were found in Las Difuntas locality of the middle Permian (Wordian–Capitanian) whereas Cyclocaudex typicus, C. sp., Preptopremnum laeve and Epicrinus torreonense were also found in Las Sardinas locality whose strata have been dated as early Permian (Kungurian-Roadian). The occurrence of all parataxa in strata from the middle Permian of the Las Delicias Formation allowed extending their stratigraphic range until the Wordian–Capitanian. Most species described have been associated to the Grandian Paleoprovince, nonetheless, the presence of Floricyclus and Pentagonopternix parataxa in the Permian of Coahuila proves the cosmopolitan nature of both genera.