The oldest stratigraphic record of the Late Cretaceous shark Ptychodus mortoni Agassiz, from Vallecillo, Nuevo León, northeastern Mexico

  • Alberto Blanco-Piñón Centro de Investigaciones en Ciencias de la Tierra, Universidad Autónoma del Estado de Hidalgo, Apdo. Postal 1-288, Admón. 1, 42001 Pachuca, Hidalgo, Mexico..
  • Luis M. Garibay-Romero Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México, D.F., Mexico. Universidad Autónoma de Guerrero, Unidad Académica de Ciencias de la Tierra, Ex-Hacienda de San Juan Bautista, Taxco el Viejo, Guerrero. Mexico.
  • Jesús Alvarado-Ortega Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México, D.F., Mexico.
Keywords: Ptychodus mortoni, shark, lower Turonian, Late Cretaceous, Vallecillo, Mexico.

Abstract

In this paper we report the oldest geologic world record of Ptychodus mortoni, from the Vallecillo Member (Agua Nueva Formation), at Vallecillo, Nuevo León, northeastern Mexico. The presence of the ammonite Watinoceras coloradoense, allows the placement of the sediments of the Vallecillo member within the lower Turonian (Watinoceras coloradoense zone). With reference to this new data, the presence of Ptychodus mortoni in the Vallecillo member extend the temporal distribution of this species into the earliest Turonian. Also, this study suggests that the utility of this shark species as biostratigraphic control in late Cretaceous sediments should be revised in greater detail.

Published
2018-02-22
Section
Articles