UNA NUEVA ESPECIE DE TOUCASIA EN EL CRETACICO MEDIO DE LOS ESTADOS DE OAXACA Y PUEBLA,EQUINOIDES DEL CRETÁCICO MEDIO DE COLIMA,TETRAGRAMMA GLORIAE N. SP., EQUINOIDE DE LA FORMACIÓN SAN LUCAS (HUATERIVIANO-APTIANO) DE LA REGIÓN DE HUETAMO, MICHOACAN.

In the Mixteca  Alta region of the state of Oaxaca, and in the southeast of the State of Puebla, there are several outcrops of a biostroma interstratified with beds of the Teposcolula Limestone, or of the Cipiapa Formation. A new species which is now named Toucasia polygyra , constitutes the biostroma. Because of its great resemblance with Toucasia patagiata (White) , from the Albian of Texas, and its association with Chondrodonta musoni (Hill) and Coalcomana ramose (Boehm), it is concluded that the new species characterizes an age extended from the late Albian to the Cenomanian. It is discussed briefly the way of life of the species and the difficulties in the study of this group of requieniid rudists when the specimens are not adequately preserved.