BioOne.org will be down briefly for maintenance on 12 February 2025 between 18:00-21:00 Pacific Time US. We apologize for any inconvenience.
How to translate text using browser tools
1 January 2010 A New Small Short-Snouted Dyrosaurid (Crocodylomorpha, Mesoeucrocodylia) from the Paleocene of Northeastern Colombia
Alexander K. Hastings, Jonathan I. Bloch, Edwin A. Cadena, Carlos A. Jaramillo
Author Affiliations +
Abstract

The fossil record of dyrosaurid crocodyliforms spans the Late Cretaceous to Middle Eocene of Africa, Asia, Europe, North America, and South America. Prior to this study, specimens from South America have been limited to a few fossils with only two taxa diagnosed. We describe a nearly complete skull and unassociated mandible of a new dyrosaurid, Cerrejonisuchus improcerus gen. et sp. nov., from the Paleocene Cerrejón Formation of northeastern Colombia. The skull of C. improcerus has relatively elongate supratemporal fenestrae and well-developed occipital tuberosities, both diagnostic characteristics of Dyrosauridae. The rostrum of adult C. improcerus comprises 54–59% of the length of the skull, making it the shortest snout of any known dyrosaurid. A cladistic analysis using 82 cranial and mandibular characters for all species of Dyrosauridae known from crania yielded two most-parsimonious cladograms with C. improcerus as the sister taxon to a clade including Arambourgisuchus, Dyrosaurus, Hyposaurus, Congosaurus, Rhabdognathus, Atlantosuchus, and Guarinisuchus. Only Chenanisuchus, Sokotosuchus, and Phosphatosaurus, all known only from Africa, are more primitive within Dyrosauridae. Chenanisuchus from the Paleocene of Morocco, the only other known short-snouted dyrosaurid, is not closely related to C. improcerus and a short-snouted condition appears to have evolved independently at least twice within Dyrosauridae. Our analysis supports an African origin of Dyrosauridae with dispersals to the New World by the Late Cretaceous or earliest Paleocene. The presence of C. improcerus, together with undescribed taxa from the Cerrejón Formation, suggests a radiation of dyrosaurid crocodyliforms, possibly following the K-P boundary, in tropical South America.

© 2010 by the Society of Vertebrate Paleontology
Alexander K. Hastings, Jonathan I. Bloch, Edwin A. Cadena, and Carlos A. Jaramillo "A New Small Short-Snouted Dyrosaurid (Crocodylomorpha, Mesoeucrocodylia) from the Paleocene of Northeastern Colombia," Journal of Vertebrate Paleontology 30(1), 139-162, (1 January 2010). https://doi.org/10.1080/02724630903409204
Received: 11 December 2008; Accepted: 1 March 2009; Published: 1 January 2010
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top