Pachyrhizodus caninus Cope, 1872 (Teleostei, Crossognathiformes) from the early Turonian of Vallecillo (Mexico)

In this paper we report on a specimen of Pachyrhizodus caninus Cope, 1872 (Teleostei, Crossognathiformes) from the early Turonian of Vallecillo (North-eastern Mexico). P. caninus is considered to be a typical faunal element of the Western Interior Seaway, however, its occurrence in Vallecillo shows that this species was not restricted to the Seaway realm. The described specimen is the stratigraphically oldest record of this species. Comparisons with the European type species Pachyrhizodus basalis (Dixon, 1850) show that both P. caninus and P. basalis are valid species. The occurrence of a Western Interior faunal element in the assemblage of Vallecillo underlines the importance of this locality in understanding the palaeobiogeographical relations of the Western Tethys and adjacent realms in the late Cretaceous.