Osículos columnares de crinoideos pérmicos, incluidos dos géneros nuevos, de la Formación Grupera (Asseliano-Sakmariano) de Chiapas, México

摘要

Eleven morphotypes of columnar ossicles of Permian crinoids collected from the Grupera Formation (Asselian?Sakmarian) are described. Floricyclocion heteromorpha and Cyclo-grupera minor are proposed as new morphogenera and morphospecies. Preserved elements allow relating the depositional paleoenvironment to restricted waters of the inner ramp. The stratigraphical range of Cyclo-caudiculus regularis, Heterostelechus keithi, Lamprosterigma erathense and Cyclocaudex insaturatus is extended from the Pennsylvanian (Upper Carboniferous) to the lower Cisuralian (lower Permian). The record of all parataxa studied is the first in Chiapas, Mexico, and the first formal work on Permian crinoids from the Chicomuselo region. Because the specimens were found in a Permian unit that had been related to the Grandian Province of North America (Texas and New Mexico in USA; Coahuila, Sonora and Chiapas in Mexico; and Palmarito in Venezuela), it is suggested that crinoids should be part of the same paleoprovince.