Morphology and Ontogeny of Palaeocastor peninsulatus


I am interested in burrowing rodents and Arikareean faunas of Montana. As a consequence, I have worked on the palaeocastorine fauna (burrowing beavers) from the Fort Logan Formation (Montana). This fauna includes at least three different taxa. My work has focused on one of these: Palaeocastor peninsulatus. This animal was previously known only from Oregon. The material available from the Fort Logan Formation of Montana includes a juvenile, a sub-adult and an adult. These fossils curated at the University of Washington Burke Museum of Natural History include numerous elements of the post-cranial skeleton giving us an insight into the development of P. peninsulatus, its morphology and paleoecology.

This article is available online. It was mentioned and summarized on the UW BioGrad blog.

Calede, J. 2014. Skeletal morphology of Palaeocastor peninsulatus (Rodentia, Castoridae) from the Fort Logan Formation of Montana (Early Arikareean): ontogenetic and paleoecological interpretations. Journal of Mammalian Evolution 21: 223-241.

Antelope astragali


The Hemphillian (~8Ma) Thousand Creek Fauna of northwestern Nevada contains three species of closely related antilocaprids in two genera, Ilingoceros alexandrae, Ilingoceros schizoceras, and Sphenophalos nevadanus. These species were diagnosed on the basis of their distinct horn morphology, but the little work done comparing their dental or postcranial morphology showed no clear separation between the species, leading to a hypothesis that the two Ilingoceros were age classes and that Ilingoceros and Sphenophalos represented sexual morphs within one species. We used multivariate morphometric comparison of eight linear dimensions of >200 antilocaprid astragali from Thousand Creek to find out if there is enough variation to support the presence of more than one species.

Preliminary results have been presented by Dr. Edward Davis at the annual meeting of the Society of Vertebrate Paleontology in Austin (2007). The results of this research project are published in Palaeontologia Electronica.

Davis, E. B., and Calede, J.2012. Multivariate analysis of Hemphillian (Late Miocene) and recent antilocaprid astragali indicates little divergence between Ilingoceros and Sphenophalos in the Thousand Creek Formation, Nevada. Paleontologia Electronica 15.1.1A.
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Collaborator: Edward Davis

Morphology and Ontogeny of Alphagaulus pristinus


My undergraduate research project at the University of Oregon (during an exchange program) focused on understanding changes in morphology during ontogeny in the poorly known Alphagaulus pristinus described in 1903 by Douglass on the basis of a single isolated partial jaw.

The results of this research were presented at the SVP annual meeting in 2008 and are published in the Journal of Vertebrate Paleontology.

Calede, J., and Hopkins, S.S.B. 2012. New material of Alphagaulus pristinus (Mammalia: Rodentia: Mylagaulidae) from the Deep River Formation (Montana, USA): implications for ecology, ontogeny, and phylogeny. Journal of Vertebrate Paleontology 32:151–165.
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Collaborator: Samantha Hopkins