Hi all! Just a little update here on my research. Yesterday, a preprint of mine (Brownstein, 2018) describing the first piece of a theropod braincase known from the Late Cretaceous of New Jersey was published at PeerJ Preprints. What follows is a little summary of the research.
As you all know, the fossil record of terrestrial animals from the Cretaceous of North America is poor, especially when compared to that of the American West. Nevertheless, recent discoveries have allowed us to fill in some of the gaps regarding eastern North American dinosaurs. One such gap is our record of dinosaur cranial material from the eastern United States. Material from the skulls of dinosaurs is super rare in this area, and so any chunk can potentially tell us a lot about eastern North American dinosaur anatomy and evolution.
One such specimen is the possible partial prootic (a bone on the side of the braincase) of a juvenile tyrannosauroid dinosaur collected in the mid-1990s from the Ellisdale site of New Jersey. The bone is actually in pretty good condition. The unfused sutures on all sides of the specimen and the prootic’s small size suggest it belonged to a juvenile animal, thus representing one of the few immature dinosaur specimens from northeastern North America.
The prootic in question.
The prootic can tell us several things about eastern North American dinosaurs, including that their braincases were similar in several ways to those of mid-Cretaceous tyrannosauroids from Asia like Timurlengia (Brusatte et al., 2016). The morphology of the prootic overall supports the notion that Appalachian tyrannosauroids were evolutionarily somewhere between the Tyrannosauridae and the basal tyrannosauroids of the Jurassic and Early Cretaceous.
Stay tuned for more, and thanks for reading!
References.
(2018) Prootic anatomy of a juvenile tyrannosauroid from New Jersey and its implications for the morphology and evolution of the tyrannosauroid braincase. PeerJ Preprints6:e26467v1 https://doi.org/10.7287/peerj.preprints.26467v1
New tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies evolution of giant body sizes and advanced senses in tyrant dinosaurs. Proceedings of the National Academy of Sciences of the United States of America 113(13):3447–3452
An Odyssey of Time 