UPPER CRETACEOUS ZINGIBERALEAN FRUITS WITH IN-SITU SEEDS FROM SOUTHEASTERN COAHUILA, MEXICO

In the southeastern region of Coahuila, Mexico, 1,844 fruits with char acteristics that relate them to the order Zingiberales have been recov ered from Upper Cretaceous (Campanian) sediments. They are tricarpella te and trilocular and have axial placentation and numerous anatropous, operculate, small seeds per locule. Two types of fruits are distingui shable. Striatornata sanantoniensis gen. et sp. nov. is closely relate d to Spirematospermum, and both are interpreted as members of the Musa ceae based on the presence of a chalazal chamber and hilar cavity. Tri costatocarpon silvapinedae gen. et sp. nov. is difficult to accommodat e within an extant family of the Zingiberales; however, the opercular structure, integumentary anatomy, and general fruit morphology strongl y support its recognition as a member of the order, perhaps related to Musa cardiosperma. Comparison of integumentary anatomy reveals that w hile the integuments of the fossil seeds have a similar construction p attern, this is not comparable to any of the patterns so far known amo ng the seeds of extant members in Zingiberales, indicating changes in the reproductive biology of the order.