Nasutoceratops titusi (Ornithischia, Ceratopsidae), a basal centrosaurine ceratopsid from the Kaiparowits Formation, southern Utah

ABSTRACT

The skull and associated postcrania of Nasutoceratops titusi, a basal centrosaurine ceratopsid from the Upper Cretaceous (Campanian) Kaiparowits Formation of Grand Staircase–Escalante National Monument, southern Utah, are herein described. Autapomorphies of this taxon include: an ectonaris that comprises 75% of preorbital skull length; pneumatic nasals; a hyper-robust premaxilla–maxilla contact; a double-faceted, medial flange on the maxilla contributing to the hard palate; and unique supraorbital horncores that are anterolaterally directed, anteriorly curved, torsionally twisted, and relatively enormous. A Bayesian analysis, the first conducted for ceratopsians, is coupled with a parsimony phylogenetic analysis of Centrosaurinae, with both analyses recovering Nasutoceratops as the sister taxon to Avaceratops lammersi from the late Campanian of Montana. Nasutoceratops titusi provides insights into the origins of Centrosaurinae and suggests the existence of a previously unknown clade of short-snouted, long-horned centrosaurines that we here hypothesize to have originated in the southern Western Interior Basin of North America.

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Citation for this article: Lund, E. K., S. D. Sampson, and M. A. Loewen. 2016. Nasutoceratops titusi (Ornithischia, Ceratopsidae), a basal centrosaurine ceratopsid from the Kaiparowits Formation, southern Utah. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1071265.

ACKNOWLEDGMENTS

We thank A. Titus, Grand Staircase–Escalante National Monument, and the Bureau of Land Management for their continuing support of the Kaiparowits Basin Project in GSENM; the 2006 GSENM field crew, especially S. Beardmore, P. Policell, and S. Neabore; and M. Getty (Denver Museum of Nature and Science) for critical field, laboratory, and collections support. We also thank R. Butler, P. Dodson, J. Scannella, and D. Evans for detailed and helpful reviews, which undoubtedly improved the article, and P. O'Connor for helpful discussions. Funding for this study was provided by the University of Utah, as well as grants from the Bureau of Land Management (Grand Staircase–Escalante National Monument) and the National Science Foundation (EAR 0745454, 0819953).

Submitted April 29, 2014; revisions received April 17, 2015; accepted May 3, 2015.

Handling editor: Richard Butler.