This morning I attended a special symposium on the Late Cretaceous fossils from Appalachia. In this context, Appalachia is not simply the Appalachian Mountains. During the Late Cretaceous North America was bisected by the Western Interior Seaway, dividing the continent into two land masses: Laramidia to the west and Appalachia to the east. Laramidia Cretaceous deposits have been intensively studied, and have produced massive numbers of fossils including Triceratops and Tyrannosaurus. The more limited Cretaceous exposures in Appalachia have not received as much attention, especially in the last 100 years or so. Yet there’s a surprising amount of fossil material from these deposits.
Much of the early vertebrate paleontology work in North America took place in the Cretaceous deposits of New Jersey, as reviewed by Barbara Grandstaff and David Parris. Many of the symposium talks were about the faunas at other specific sites, such as those by Bill Garcia and Scott Hippensteel (North Carolina), Cynthia Crane (also North Carolina), David Schwimmer (Georgia), Michael Fix et al. (Missouri), Derek Main et al. (Texas), and Matthew Vavrek and Hans Larsson (Nunavut). Most of the Appalachia deposits are marine or deltaic, and include a range of shark, ray and fish remains. There are also diverse tetrapods, including large numbers of the giant crocodile Deinosuchus in Georgia as reported by Schwimmer. The most common ornithischian dinosaurs were hadrosaurs (Hadrosaurus was the first dinosaur ever described from North America). As described by Stephen Brusatte et al., there are also several types of theropods, including ornithomimosaurs and the tyrannosauroids Dryptosaurus and Appalachiosaurus.
I unfortunately missed the afternoon talks, but I did make it to the poster session. Ali Nabavizadeh examined how the jaw musculature of elephants has changed over time, so that the trunk morphology and bite style of Gomphotherium (above) would have been quite different from a modern elephant’s. Geb Bennett et al. discussed the fauna and depositional setting at the Cretaceous Arlington Archosaur Site in Texas, in a follow-on to Derek Main’s talk in the Appalachia symposium. Daniel Snyder and Susan Turner discussed a freakishly deformed fin spine from the Devonian acanthodian fish Gyracanthides. Tony Martin, author of the blog Life Traces of the Georgia Coast, and colleagues presented data on modern alligator burrows on St. Catherines Island in Georgia. Alligators don’t spend all their time sunning themselves like the example below; they also dig large burrows, big enough for them to turn around. I was disappointed to hear that Tony doesn’t crawl down the burrows to map them, but uses ground-penetrating radar instead!