Sunday, December 16, 2012
Obamadon is Not a Dinosaur
This illustration of Hell Creek fauna at the end of the Cretaceous is the work of Carl Buell [FB]. The big bad in the foreground chasing baby edmontosaurs is Palaeosaniwa. The little blue fellow is a polyglyphanodontian lizard called Obamadon. It is not a dinosaur.
The large fellows in the distance, who you might rightly guess to be Tyrannosaurus and Triceratops? Those are dinosaurs. Palaeosaniwa's breakfast? Those little green dumplings are dinosaurs. Obamadon, I'm sorry to report, is not. A page or two of web search results may lead you to believe it may be a dinosaur, but it is not a dinosaur.
Buell's artwork accompanies press about new research published in the Proceedings of the National Academy of Sciences studying the effect of the end-Cretaceous mass extinction on squamates - lizards and snakes - from Nick Longrich, Bhart-Anjan S. Bhullarb, and Jacques A. Gauthiera. They find that while the exact cause or causes of the extinction are still debated, a devastating and sudden loss in squamate diversity at the K-Pg boundary supports the Chicxulub impact hypothesis. While squamates have generally been seen as coming through the extinction relatively unscathed, Longrich and team found that less than a quarter of species persisted, and these were small and geographically widespread. Today's great diversity of squamate life took tens of millions of years to rise from the catastrophe. Longrich writes in his conclusion that "...the squamate fossil record provides a striking example of how mass extinction works as a form of creative destruction, and shows how the origins of the modern biota can be understood only in light of catastrophes occurring in deep time."
This paper erects a number of new squamate species, one of which is Obamadon. However, being a Cretaceous species does not grant our plucky little lizard membership in the esteemed ranks of the dinosaurs. Still a squamate, despite what headline writers, journalists slumming it in the science beat, and giddy political columnists might have you believe.
Distinguishing this extinct lizard from dinosaurs is just too much hassle when you've got a puff piece to crank out, or a witty analogy about the fiscal cliff and the K-Pg extinction to bestow upon your delighted readers.
Yes, Virginia, there is an Obamadon. But it's not a dinosaur.