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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 suggest 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 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.

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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

 

 

Paper Published: A tyrannosauroid metatarsus from the Merchantville formation of Delaware increases the diversity of non-tyrannosaurid tyrannosauroids on Appalachia

Hi all. Today, a paper of mine regarding a tyrannosauroid metatarsus from the Merchantville Formation of Delaware housed in the Yale Peabody Museum was published in PeerJ, and I figured I’d give a few words on it here. 

Tyrannosauroids are poorly known east of the Mississippi, their fossil record in eastern North America consisting of the holotypes of Appalachiosaurus and Dryptosaurus, additional specimens referred to these taxa, and other fragmentary elements. These all seem to come from genera more closely related to derived tyrannosauroids outside Tyrannosauridae, but the small number of Appalachian tyrannosauroid specimens included in past phylogenetic analyses of Tyrannosauroidea has hindered the investigation of this possibility.

That’s where the Yale Peabody specimen YPM VPPU.021795 comes in. Though the bones included in this set are all only partially preserved and consist of two metatarsals, they provide new evidence for the hypothesis that Appalachian dinosaur genera were generally more basal than their western relatives. Furthermore, the specimen is different enough from Appalachiosaurus and Dryptosaurus that it likely represents a distinct animal (which I did not name due to the small amount of material included in YPM VPPU.021795).

You can find the paper below, and thanks so much for reading:

Brownstein CD. (2017A tyrannosauroid metatarsus from the Merchantville formation of Delaware increases the diversity of non-tyrannosaurid tyrannosauroids on AppalachiaPeerJ5:e4123 https://doi.org/10.7717/peerj.4123

 

 

 

 

 

 

 

 

Preprint Published: Theropod Specimens from the Navesink Formation

Hi there everyone. I just wanted to note that my preprint on ornithomimosaur and tyrannosauroid hindlimb elements from the Maastrichtian Navesink Formation of Monmouth County, New Jersey, has been published. Recently, the taxon “Teihevenator” was erected by Yun (2017)(it’s a nomen nudum because the Zoobank LSID for the name wasn’t included in the paper and the paper doesn’t seem to publish copies)(for more discussion of this see my preprint on a tyrannosauroid from the Merchantville Formation of Delaware(1) and this post at the Theropod Database Blog). I was also working on these specimens during the time Yun (2017) was published describing AMNH 2550-2553 as a new genus, with myself describing them as a chimaera of ornithomimosaur and tyrannosauroid remains. As such, upon hearing of the publication of Yun (2017), I finished up my figures of the specimens and submitted it for publication as a preprint, which you can find here. I love hearing from all of you, so please don’t hesitate to leave comments on this post or on the preprint itself regarding the manuscript!

Thanks again for reading!

 

Refs-

Yun C. 2017. Teihivenator gen. nov., a new generic name for the tyrannosauroid dinosaur “Laelaps” macropus (Cope, 1868; preoccupied by Koch, 1836). Journal of Zoological and Bioscience Research 4(2):7-13.

 

Footnotes-

(1) The metatarsals II and IV are from Delaware. Though I only named the state of discovery of these specimens twice incorrectly in the manuscript, I made an error and for some odd reason thought the specimens were found several miles east of Summit Bridge. This error has been corrected in my working copy of the manuscript and I have addressed it by adding an erratum in the comments section of the manuscript.

 

 

Preprint Published: A Tyrannosauroid Metatarsus from the Merchantville Formation of Delaware increases the diversity of non-Tyrannosaurid Tyrannosauroids on Appalachia

Hello everyone. Recently, I have worked on describing several tyrannosaur specimens from the Cretaceous Formations of Atlantic Coastal Plain. One of the manuscripts I have written concerns a partial tyrannosaur metatarsus from the Merchantville Formation of Delaware. As of now, the preprint of this paper has been published, and you can find it here:

https://peerj.com/preprints/3097/

The metatarsus represents a distinct morphotype of tyrannosaur from Dryptosaurus or Appalachiosaurus, but nevertheless is too incomplete and lacking in distinguishing features to warrant the naming of a new specimen. Certainly, the diversity of tyrannosauroids on Appalachia has been underestimated.

 

An Interesting Encounter at Lunch: Chelydra serpentina

Hi everyone! This will be a short post, but one regarding an interesting sighting I had while having lunch at a local diner today. The diner, known aptly as the Lakeside Diner (info), sits on a lake that is frequented by many bird species. Besides the common grackle, blue jay, and house sparrows I saw today, a denizen of the water made an appearance. As a brown rat was getting ready to head back into the lake, a large beak made a splash as it grabbed the poor rodent and dragged it into the abyss. It was none other than the maw of a common snapping turtle, Chelydra serpentina.

This turtle, covered in knobs and scales, was around three or so feet in length. It was quite the cryptodiran. As it plunged back into the murky water, I was able to get some photos of its rugged back and tail. Here they are:

IMG_3242.jpgIMG_3240.JPG

It goes to show that even in the suburban setting of Stamford, Connecticut, truly incredible species may be found.

Earth Day 2017: A Call to be Active in Conservation and Environmentalism

Ever since the end of 2016, I’ve been obsessively scrolling around the planet on Google Earth in my spare time. I’ve realized that I’m not doing this because I’m worried about what we might lose in the future, but because I’m nervous of what we have already lost today. Perhaps this notion of mine is because of my work and interest in paleontology. I’m liable to be looking to the past, not the present. Our current crisis, however, is too close for comfort for me, even in looking at it with a purely scientific perspective.

Late in the afternoon today, I took a hike in the Mianus River Gorge Preserve (their website is here), a beautiful stretch of land in New York that preserves an old growth forest of Hemlock trees that was not logged and turned into farmland because the hemlocks took up residence on the steep slopes of the gorge. This preserve was actually the first of the Nature Conservancy’s preserves and the first National Natural History Landmark in the United States , and walking through the gorge and old growth forest gave me a minute or two to think about conservation in general.

The land of the preserve bears biological stains from when humans exploited the countryside for its land, with the difference between the old-growth forest and the secondary growth forest growing on the slope above collapsed stone walls stark. Deforestation leaves its scars. As I read about the sudden uptick in deforestation in the Amazon rainforest, the old rock walls which populate the forest floor around myself come to mind.

In previous years, I’ve written articles on this blog on Earth day in celebration. I’m not so sure I can today. Science and the environment are under heavy attack from powerful forces political and economic. It’s up to everyone to stand up for the planet, as many demonstrated today by marching at the March for Science and its sister marches across the globe. Though I couldn’t join them today, I’ve been for my part trying to contact my legislators as much as possible regarding conservation and other issues and donating to conservation organizations among others when I can. Yet the scariness of the moment doesn’t cease. All I can say is that I think it’s going to be a long few years ahead for science and conservation, but with a little luck and a lot of work things will turn out all right. Happy Earth Day.

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Rocky Mountain National Park, Colorado. Photo by the author.