Protexanites thompsoni Jones n. sp. from the Upper Cretaceous Funks Formation of Kirby (1943) in California has an early trituberculate stage and a later quadrituberculate stage, both characteristic of Protexanites; however, at a large diameter a pentatuberculate stage characteristic of Texanites appears. The suggested geologic age of this new species is late Coniacian or early Santonian.