Analyses

Paper Published: Appalachian Dinosaur Biogeography and Ecology

After four years of research, I am very pleased to announce that my paper reviewing all known Appalachian dinosaur faunas and analyzing Appalachian dinosaur biogeography and ecology was published in the journal Paleontologia Electronica (Brownstein, 2018). As usual, I will give an overview of the paper on this website.

In the past several years, we’ve learned a considerable amount about many aspects of Laramidian dinosaur biology, including their ecology, evolutionary relationships, and distribution. Such research has manifested in papers like Lehman (1997), Gates et al. (2010), Sampson et al. (2010), Gates et al. (2012), Sampson et al. (2013), etc. However, a major gap has persisted in the data, stemming from the poorly-documented fossil record east of the American Interior.

The new paper, which systematically reviews the dinosaurs of each fauna known from eastern North America and compares them using the Simpson similarity index, Jaccard coefficient, and Jaccard distance (e.g., Jaccard, 1902; Simpson, 1943), was written by me with the intention of helping to alleviate this issue.

My analyses seem to suggest several points about Appalachian dinosaur genera. Firstly, the data suggests that Appalachian dinosaurs represented relict forms surviving in isolation, an often-proposed hypothesis (Denton and O’Neill, 1995, 1998; Schwimmer, 1997; Kiernan and Schwimmer, 2004). Additionally, dinosaur provincialism on Appalachia seems to (maybe) be a thing, something proposed by Schwimmer (2016). Finally, competition between predatory dinosaurs and large crocodylians is also discussed, a topic that has actually attracted quite a lot of attention that has resulted in several extensive pieces of literature (e.g., Gallagher, 1995; Schwimmer, 2002; Noto et al., 2012).

I’d like to extend my utmost gratitude to all the researchers who provided me with information for this project and to everyone at PE for their helpfulness in getting this piece of research out there.

Refs.-

  1. Brownstein, CD. 2018. The biogeography and ecology of the Cretaceous non-avian dinosaurs of Appalachia. Paleontologia Electronica 21.1.5A: 1-56. DOI: https://doi.org/10.26879/801
  2. Lehman TM. 1997. Late Campanian dinosaur biogeography in the western interior of North America, p. 223-240. In: Wolberg D, Stump E, eds: Dinofest International Proceedings. Philadelphia Academy of Natural Sciences, Philadelphia,  USA.
  3. Gates TA, Sampson SD, Zanno, LE, Roberts, EM, Eaton, JG, Nydam RL, Hutchison JH, Smith JA, Loewen MA, Getty MA. 2010. Biogeography of terrestrial and freshwater vertebrates from the Late Cretaceous (Campanian) Western Interior of North America. Palaeogeography, Palaeoclimatology, Palaeoecology 291:371-387. https://doi.org/10.1016/j.palaeo.2010.03.008
  4. Sampson SD, Loewen MA, Farke AA, Roberts EM, Forster CA, Smith JA, Titus AL. 2010. New horned dinosaurs from Utah provide evidence for intracontinental dinosaur endemism. PLoS ONE 5(9):e12292.
  5. Gates TA, Prieto-Márquez A, Zanno LE. 2012. Mountain building triggered Late Cretaceous North American megaherbivore dinosaur radiation. PLoS ONE 7(8):e42135. https://doi.org/10.1371/journal.pone.0042135
  6. Sampson SD, Loewen MA, Roberts EM, Getty MA. 2013. A new macrovertebrate assemblage from the Late Cretaceous (Campanian) of southern Utah, p. 599-617. In: Titus AL, Loewen MA, eds: At the Top of the Grand Staircase: The Late Cretaceous of Southern Utah. Indiana University Press, Bloomington, USA.
  7. Jaccard P. 1902. Lois de distribution florale. Bulletin de la Socíeté Vaudoise des Sciences Naturelles 38:67-130.
  8. Simpson GG. 1943. Mammals and the nature of continents. American Journal of Science 241:1-31.
  9. Schwimmer DR. 1997. Late Cretaceous dinosaurs in Eastern USA: A taphonomic and biogeographic model of occurrences, p. 203-211. In: Wolberg E, Stump E, eds: Dinofest International Proceedings. Philadelphia Academy of Natural Sciences, Philadelphia, USA.
  10. Denton RK, O’Neill RC. 1995. Prototeius stageri, gen. et sp. nov., a new teiid lizard from the Upper Cretaceous Marshalltown Formation of New Jersey, with a preliminary phylogenetic revision of the Teiidae. Journal of Vertebrate Paleontology 15(2):235-253.
  11. Denton RK, O’Neill RC. 1998. Parrisia neocesariensis, a new batrachosauroidid salamander and other amphibians from the Campanian of eastern North America. Journal of Vertebrate Paleontology 18(3):484–494.
  12. Schwimmer DR. 2016. Was there a southeastern dinosaur province in the Late Cretaceous?. Geological Society of America Abstracts with Programs 48(3):22-23.
  13. Gallagher WB. 1995. Evidence of juvenile dinosaurs and dinosaurian growth stages in the Late Cretaceous deposits of the Atlantic Coastal Plain. Bulletin of the New Jersey Academy of Science 40:5-8.
  14. Schwimmer DR. 2002. King of the Crocodylians: The Paleobiology of Deinosuchus. Indiana University Press, Bloomington, USA.
  15. Noto CR, Main DJ, Drumheller, SK. 2012. Feeding traces and paleobiology of a Cretaceous (Cenomanian) crocodyliform: Example from the Woodbine Formation of Texas. Palaios 27(2):1-11.
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Preprint Published: Tyrannosaur brains from the eastern US

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 skull of dinosaurs in this area is super rare, and so any chunk can potentially tell us a lot about eastern North American dinosaur anatomy and evolution.

One such specimen is the 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, which allowed me to assign it to a tyrannosauroid. The unfused sutures on all sides of the specimen and the prootic’s small size suggest it belonged to an unfortunate juvenile animal, thus representing one of the few juvenile dinosaur specimens from eastern North America.

 

IMG_4556

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.

Brownstein CD. (2018Prootic anatomy of a juvenile tyrannosauroid from New Jersey and its implications for the morphology and evolution of the tyrannosauroid braincasePeerJ Preprints6:e26467v1 https://doi.org/10.7287/peerj.preprints.26467v1

Brusatte SLAverianov ASues HDMuir AButler IB. 2016. 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):34473452