A new specimen of marine crocodile from the Middle Jurassic of northern Chile: revalidation of Metriorhynchus westermanni (Crocodyliformes: Metriorhynchidae)

Abstract

A new specimen of a Callovian marine crocodile (Metriorhynchidae), found in the middle course of quebrada Cherejara, Sierra del Medio, Región de Antofagasta, Chile, allows the revalidation of the species Metriorhynchus westermanni Gasparini. The analysis of the braincase and associated bones shows that the holotype ofMetriohrynchus westermanni is not a juvenile ofM casamiquelai Gasparini and Chong, as recently proposed. Revalidation of M. westermanni is supported by several morphological differences such as frontal and parietal on a single plane, absence of medial depression on the interorbital section of the frontal, base of the supratemporal fossa flat and horizontal, internal nares drop-shaped with the base wider caudally and separated by a complete septum. The revalidation ofM westermanni increases the diversity of Jurassic marine crocodiles in West Gondwana, prevailing the Chilean forms during the Mddle Jurassic.