PaleoNews #22: New Years 2016

PaleoNews #22: New Years 2016

Happy new year! It’s been an interesting year this time around, full of new discoveries pertaining to the landmass of Appalachia.

NEW FINDINGS THIS YEAR 

Perhaps the most covered story of a discovery from Appalachia was of the landmass’s newest hadrosaur. Eotrachodon orientalis, known from the likely juvenile holotype specimen MSC 7949, is the only named pre-Campanian non-lambeosaurine hadrosaurid and helps to fill in some of the gaps regarding the evolution of the hadrosaurid dinosaurs (Prieto-Márquez, Erickson & Ebersole, 2016a; 2016b). Eotrachodon is known from the Mooreville Chalk Formation, which has also preserved the remains of the hadrosauroid dinosaur Lophorhothon, the dromaeosaurid Saurornitholestes, and the alligatoroid crocodyliform Deinosuchus (e. g. Schwimmer, 2002; Kiernan & Schwimmer, 2004;Prieto-Márquez, Erickson & Ebersole, 2016a; 2016b). The holotype specimen of this dinosaur is surprisingly complete for an Appalachian dinosaur specimen, consisting of a mostly complete skull and partial skeleton (Prieto-Márquez, Erickson & Ebersole, 2016a; 2016b).

Eotrachodon is especially important because it represents an extremely close outgroup to the clade containing Lambeosaurinae and Saurolophinae (Prieto-Márquez, Erickson & Ebersole,2016a). Alongside the New Jersey taxon Hadrosaurus foulkiiEotrachodon orientalis is one of the most basal hadrosaurids, suggesting that the group may have originated on Appalachia (Prieto-Márquez, Erickson & Ebersole, 2016a; 2016b).

Hadro_bones
Along with HadrosaurusEotrachodon is one of the most basal hadrosaurids. Hadrosaurus foulkii fossils displayed at the Philadelphia Academy of Natural Sciences, Drexel University. Photo from Wikipedia.

Anné, Hedrick & Schein (2016) described the radius and ulna of a hadrosaurid dinosaur from the Navesink Formation of New Jersey. The elements in question were diagnosed with septic arthritis, the first known case of the ailment to be reported from the Dinosauria (Anné, Hedrick & Schein, 2016).

The forelimb elements provide new information on ailments which affected the dinosaurs, and are also significant for being an example of paleopathology from Appalachia (Anné, Hedrick & Schein, 2016).

Paulina-Carabajal, Lee & Jacobs (2016) examined the skull of the Texan nodosaur Pawpawsaurus campbelli. The endocast of Pawpawsaurus is one of the most well-known of a nodosaurid, thus allowing Paulina-Carabajal, Lee & Jacobs (2016) to examine the morphology of the dinosaur’s inner ear in detail.

 Scans of the internal structure of the skull and brain suggest that the nodosaurid had a poor sense of hearing (Paulina-Carabajal, Lee & Jacobs, 2016). However, Pawpawsaurus was also found to have a good sense of smell, albeit less so than more derived ankylosaurian genera (Paulina-Carabajal, Lee & Jacobs, 2016).

IMG_0817.jpg
Pawpawsaurus campbelli walks along an Albian Texas shore alongside Protohadros-like hadrosauroids and a crocodyliform. 

Another nodosaurid from Appalachia was remarked on this year in the literature. Burns & Ebersole (2o16) published an abstract in the program & abstracts book of the 76th SVP annual meeting. The abstract dealt with some exciting new material of a juvenile nodosaurid from the same formation that produced Eotrachodon. The nodosaurid specimen is also one of the smallest known (Burns & Ebersole, 2016).

FEATURED FOSSIL 

This time around, we have the skull of the sebecid crocodyliform Sebecus. This large crocodyliform occupied a predatory niche in Argentina during the Eocene. IMG_3008.jpg

All in all, it has been an exciting year of discoveries regarding the landmass of Appalachia. Here’s hoping for more in the new year. Happy holidays everyone!

 

References 

  1. Prieto-Marquez A, Erickson GM, Ebersole JA. 2016. A primitive hadrosaurid from southeastern North America and the origin and early evolution of ‘duck-billed’ dinosaurs. J. Vert. Paleo. 2016; e1054495. doi: 10.1080/02724634.2015.1054495.
  2. Prieto-Márquez A, Erickson GM, Ebersole JA. Anatomy and osteohistology of the basal hadrosaurid dinosaur Eotrachodon from the uppermost Santonian (Cretaceous) of southern Appalachia. PeerJ 2016; 4:e1872. doi: https://doi.org/10.7717/peerj.1872.

  3. Schwimmer DR. King of the Crocodylians: The Paleobiology of Deinosuchus. Bloomington: Indiana University Press; 2002.

  4. Kiernan K, Schwimmer DR. First record of a Velociraptorine theropod (Tetanurae, Dromaeosauridae) from the eastern Gulf Coastal United States. Mosasaur 2004; 7:89-93.

  5. Anné J, Hedrick BP, Schein JP. 2016. First diagnosis of septic arthritis in a dinosaur. R. Soc. Op. Sci. 3: 160222. doi: 10.1098/rsos.160222.
  6. Paulina-Carabajal A, Lee YN, Jacobs LL. 2016. Endocranial Morphology of the Primitive Nodosaurid Dinosaur Pawpawsaurus campbelli from the Early Cretaceous of North America. PLoS ONE 11(3): e0150845. doi:10.1371/journal.pone.0150845.
  7. Burns ME, Ebersole J. 2016. Juvenile Appalachian Nodosaur Material (Nodosauridae, Ankylosauria) from the Lower Campanian Lower Mooreville Chalk of Alabama. J. Vert. Paleo. 2016; 76: 73B.