The Gobiosuchidae in the early evolution of Crocodyliformes

ABSTRACT

The anatomy and phylogenetic relationships of the Las Hoyas gobiosuchid (upper Barremian, La Huérguina Formation, Cuenca, Spain) are discussed on the basis of two fully articulated specimens. Phylogenetic analysis supports the monophyly of Gobiosuchidae, defined by the Las Hoyas taxon, Cassissuchus sanziuami, gen. et sp. nov., as the sister taxon of the Asian clade Gobiosuchus + Zaraasuchus. The family Gobiosuchidae is diagnosed by a large number of synapomorphies, such as the presence of extensively sutured palpebrals, ridges on the dorsal surface of the posterolateral region of the squamosal, a longitudinal ridge along the dorsolateral surface of the surangular, appendicular osteoderms, and closure of the supratemporal fenestra. Specimens attributed to Lisboasaurus estesi, a putative gobiosuchid, are evaluated and the taxon regarded as a nomen dubium. Cassissuchus sanziuami provides new evidence on the anatomy of the pectoral and pelvic girdles and the forelimb morphology in Gobiosuchidae. The phylogeny of basal Crocodyliformes supports the nested sequence of three clades: Protosuchidae, Gobiosuchidae, and ((Shantungosuchus + Sichuanosuchus) + Shartegosuchidae), but their interrelationships are only partially solved. The early evolution of Crocodyliformes is further characterized by the high number of phenotypic specializations, many of which are related to the dermal skeletal overgrowth of the temporal region, palpebrals, and osteoderms.

http://zoobank.org/urn:lsid:zoobank.org:pub:5317CCDB-FA28-4748-9712-1BC27A166108

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Citation for this article: Buscalioni, Á. D. 2017. The Gobiosuchidae in the early evolution of Crocodyliformes. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1324459.

ACKNOWLEDGMENTS

This study was finished during a sabbatical year granted by the UAM-2014 in California. I thank L. Chiappe who hosted me at LACM and gave me access to the Fruitachampsa fossil material; the University California at Santa Barbara provided me with open access to the library. I thank F. J. Poyato and J. Marugán for their support and C. Gallardo for advice in Latin nomenclature. F. C. Montefeltro and an anonymous referee made specific and precise comments to the manuscript. I also want to acknowledge D. Pol for his valuable comments, C. Mehling and my friend M. Norell who kindly took care of me at AMNH, giving me the possibility to study Zosuchus and Zaraasuchus from the collections of Mongolia; M. Lamanna and A. Henrici gave me all the facilities at the CM, where I revised Hoplosuchus kayi. The field work at Las Hoyas (Cuenca Province) was supported by Junta de Comunidades de Castilla–La Mancha and research funds by MINECO CGL-2013-42643 P. Photographs by G. Kurtz and J. L. Gracia and life restoration by M. Antón have been uploaded to http://www.yacimientolashoyas.es. The grammar was reviewed by the Linguistic Services Office of the UAM.