acipenserid

— 1989, Laurie J. Bryant, Non-dinosaurian Lower Vertebrates Across the Cretaceous-Tertiary Boundary in Northeastern Montana, Geological Sciences: Volume 134, University of California Press, page 17, A second distinct acipenserid morphotype occurs in the Hell Creek and Tullock formations. It is not found in the Lance Formation in Wyoming, although acipenserids are so rare in the Lance Formation that this is possibly the result of sampling error.