A new species of Enchodus (Aulopiformes: Enchodontidae) from the Cretaceous (Albian to Cenomanian) of Zimapán, Hidalgo, México

ABSTRACT

A new species of Enchodus (Aulopiformes: Enchodontidae) is described from a quarry exposure of the La Negra facies of the El Doctor Formation (Cretaceous: Albian to Cenomanian) in the state of Hidalgo, central México. It is an elongate fish with many generic and familial characters, including dermal ornamentation of tubercles atop rows of ridges; a palatine with a single, large tooth; and a triangular preopercle. It has a number of unique characters that include the presence of an orbitosphenoid, absence of dorsal scutes, and dorsal fin rays that share common pterygiophores. A phylogenetic analysis places the new species as the sister to Enchodus gladiolus. The new species of Enchodus is the most abundant fish species at the locality. Using mandible length as an indicator of overall size, the range in lengths suggests that this species lived at or near the locality. This is further supported by other species that have individuals of large and small sizes.

ACKNOWLEDGMENTS

We thank V. M. Bravo-Cuevas who provided background on the stratigraphy. Sergio and Ignacio Yáñez, workers of the quarry, helped to collect many of the specimens. D. A. Stanley proofread the manuscript. This work has been funded in part by the Appalachian College Association Fellowship, and the Programa Anual de Investigación (PAI-2006–2008) of the Universidad Autónoma del Estado de Hidalgo. We would also like to thank R. R. Reisz and M. V. H. Wilson for their insightful comments concerning the manuscript.