Equinoideos del Cretácico Tardío del Norte de Coahuila, México.

Ten species of fossil echinoids are herein described from different outcrops of the Austin Formation (Upper Cretaceous) in the El Freno and El Tecolote streams, located within the municipality of Jiménez, northern Coahuila. The assignment of the studied sections to the lower Campanian is based on the presence of the ammonites Scaphites hippocrepis and Delawarella delawarensis. Some of the taxa reported here, such as Cidaris texanus Clark, Salenia mexicana Schluter, Holectypus sp., Heteraster texanus Röemer, and Diplodetus sp, have also been reported at other localities in Mexico. In addition, in this paper Cidaris splendens Morton, Diplopodia hilli Clark, Orthopsis casanovai Cooke, Micraster uddeni Cooke, Mecaster batnensis (Coquand), and Diplodetus sp. are reported for the first time from Mexico, extending the paleogeographic distribution of these taxa into the western part of the proto-Atlantic Ocean. On the other hand, the presence of the species Cidaris texanus, Cidaris splendens, Selenia mexicana and Heraster texanus in the Austin Formation extends the temporal distribution of such species within the lower Campanian in Mexico and contributes to future biostratigraphic interpretations for the Cretaceous system based on echinoids. [ABSTRACT FROM AUTHOR]