Upper Cretaceous Zingiberalean fruits with in situ seeds from southeastern Coahuila, Mexico

In the southeastern region of Coahuila, Mexico, 1,844 fruits with characteristics that relate them to the order Zingiberales have been recovered from Upper Cretaceous (Campanian) sediments. They are tricarpellate and trilocular and have axial placentation and numerous anatropous, operculate, small seeds per locule. Two types of fruits are distinguishable. Striatornata sanantoniensis gen. et sp. nov. is closely related to Spirematospermum, and both are interpreted as members of the Musaceae based on the presence of a chalazal chamber and hilar cavity. Tricostatocarpon silvapinedae gen. et sp. nov. is difficult to accommodate within an extant family of the Zingiberales; however, the opercular structure, integumentary anatomy, and general fruit morphology strongly support its recognition as a member of the order, perhaps related to Musa cardiosperma. Comparison of integumentary anatomy reveals that while the integuments of the fossil seeds have a similar construction pattern, this is not comparable to any of the patterns so far known among the seeds of extant members in Zingiberales, indicating changes in the reproductive biology of the order.