Fossil Vertebrate of the Month: Bretzia pseudalces

Bretzia pseudalces antlers (on an Odocoileus skull)
From Gustafson (2015)

As I'm returning to blogging and to life as a Washingtonian after a hiatus from both, it seemed appropriate to feature an animal first described from the Evergreen State and that was recently the subject of a monograph in a journal emerging from a long hibernation.  The animal in question is Bretzia pseudalces, a deer uncovered from the Pliocene Ringold Formation of eastern Washington (while other species of Bretzia have been found across western North America, B. pseudalces is known from the Pasco Basin, along the Columbia River north of the Tri-Cities).  The Pliocene age of the Ringold Formation is significant: while deer are abundant across the continent today, they are in fact relatively recent arrivals in North America.  Much as another iconic American animal, the bison, would do in the Pleistocene, deer migrated to the continent only at the very end of the Miocene, just over 5 million years ago (as an aside, of the animals mentioned in 'Home on the Range,' only the pronghorn "antelope" has a deep evolutionary history on the North American plains).  This makes B. pseudalces one of the oldest cervids in North America and part of the first radiation of New World deer.  Superficially, it would have appeared similar to another member of this radiation, the still-extant Odocoileus.  In fact, several features differentiate the two genera, with the most readily apparent of these being the antlers.  While modern white-tailed and mule/black-tailed deer have antlers that are a series of branching tines, the antlers of Bretzia were palmate (that is, shaped like the palm of a cupped hand, as in modern moose).  Precisely how Bretzia was related to other deer remains unclear, though hopefully this will change with future research; an assessment of how the genus fits into the broader picture of cervid evolution could, among other things, help refine our understanding of how immigrant taxa respond to new environments on a large scale, a non-trivial thing in an age during which species are shifting their ranges and being introduced into new environments at unprecedented rates.  Fortunately, the groundwork for such a study has been admirably laid by the University of Oregon's Eric Gustafson, who earlier this year published a monograph on the anatomy and taxonomy of B. pseudalces in Volume 25 of the UO Museum of Natural & Cultural History Bulletin.  This makes the monograph remarkable not only because of Gustafson's scholarly achievement, but because Volume 24 was published in 1983.  Given that the earlier run of the bulletin included such highlights as the description of the saber-toothed salmon and a number of papers by the great Oregon paleontologist and pioneering paleoecologist J. Arnold Shotwell, its reemergence is both exciting and a testament to the vibrancy of paleontology in the Northwest.