Katepensaurus goicoecheai, gen. et sp. nov., a Late Cretaceous rebbachisaurid (Sauropoda, Diplodocoidea) from central Patagonia, Argentina

ABSTRACT

We describe Katepensaurus goicoecheai, gen. et sp. nov., a diplodocoid sauropod dinosaur from the Bajo Barreal Formation (Upper Cretaceous: Cenomanian–Turonian) of south-central Chubut Province, central Patagonia, Argentina. The holotypic specimen is a closely associated partial axial skeleton that includes cervical, dorsal, and caudal vertebrae. The dorsal vertebrae of Katepensaurus exhibit the following distinctive characters that we interpret as autapomorphies: (1) internal lamina divides lateral pneumatic fossa of centrum; (2) vertical ridges or crests present on lateral surface of vertebra, overlying neurocentral junction; (3) pair of laminae in parapophyseal centrodiapophyseal fossa; (4) transverse processes perforated by elliptical fenestrae; and (5) well-defined, rounded fossae on lateral aspect of postzygapophyses. Based on the results of previous phylogenetic analyses, we regard the new taxon as a member of Rebbachisauridae; more specifically, it may pertain to Limaysaurinae, a rebbachisaurid subclade that, to date, is definitively known only from southern South America. As currently understood, the rebbachisaurid fossil record suggests that the clade achieved its greatest taxonomic diversity within a few million years of its extinction during the early Late Cretaceous.

ACKNOWLEDGMENTS

For assistance with the recovery of UNPSJB-PV 1007, we thank E. Ivany, M. Krause, V. Mansilla, M. Vilardo (UNPSJB-PV), M. Lyon (CM), M. Herne (The University of Queensland, Brisbane, Australia), P. Fraley (Phil Fraley Productions, Hoboken, U.S.A.), C. Cutler and D. Zvereff (Craig Cutler Studio, New York, U.S.A.), and residents of the village of Buen Pasto (especially H. Hourcade and the staff and students of the Escuela de Buen Pasto). Juan Canale (MMCH), R. Garcia and C. Muñoz (Museo Provincial Carlos Ameghino, Cipolletti, Argentina), and J. Porfiri and J. Calvo (Centro Paleontológico Lago Barreales, Universidad Nacional del Comahue, Neuquén, Argentina) granted access to rebbachisaurid fossils in their care. This work benefited from discussions with J. Whitlock (University of British Columbia, Vancouver, Canada) and J. Canale. J. Harris (Dixie State College, St. George, Utah, U.S.A.) provided access to relevant literature. English translations of several works cited herein are freely available from the Polyglot Paleontologist Web site (http://www.paleoglot.org). The manuscript benefited from constructive comments from editors P. Barrett (The Natural History Museum, London, U.K.) and H.-L. You (Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China) and reviewers M. D’Emic (Stony Brook University, Stony Brook, U.S.A.), P. Mannion (Imperial College London, London, U.K.), and J. Whitlock. This research was supported by the Centro Nacional Patagónico (CENPAT–CONICET), the Jurassic Foundation (grant to LMI in 2011), the CM (Edward O’Neil Field Research Fund grants to MCL in 2006 and 2007), the Facultad de Ciencias Naturales of the UNPSJB, and the Curtice family (Mesa, U.S.A.), whose generous contribution to the UNPSJB-PV in 2003 supported the expedition that discovered the Katepensaurus type locality.

Handling editor: You Hailu