Article: Description of Arundel Clay ornithomimosaur material and a reinterpretation of Nedcolbertia justinhofmanni as an “Ostrich Dinosaur”: biogeographic implications

Hi there everyone! My article on ornithomimosaur remains from the Arundel Formation of Maryland was published today at the journal PeerJ. If you have time and are interested in Cretaceous dinosaurs from eastern North America, please check it out here. That’s all for now.

P.S. I have been very busy with several things lately, but I hope to write a few new blog posts in the coming weeks. Thanks again for reading.

A Woman to be Inspired by: Mignon Talbot

Happy International Women’s Day everyone! Today, we are reminded of the struggles women have faced and still face around the globe as well as the countless contributions women have made and continue to make today to our world. I thus wanted to highlight one woman who contributed to paleontology in the eastern United States.

Mignon Talbot was born four years after the end of the Civil War in Iowa City, Iowa (Elder, 1982) Receiving her undergraduate education at Ohio State University, Talbot would go on to Yale to receive her doctorate in 1904 and would be appointed as an instructor of geology at Mt. Holyoke the same year (Elder, 1982). Dr. Talbot quickly ascended the ranks to become the chairman of the Geology department in 1908, and in 1929 would become chairman of both the Geology and Geography departments (Elder, 1982).

Over the course of her career, Dr. Talbot would greatly expand the Triassic ichnofossil and mineral collection at Mt. Holyoke, continuing to passionately do so even after a fire in 1916 would destroy most of the collection (Elder, 1982).

She would also publish a review of crinoids from the early Devonian (Helderbergian) strata of the state of New York (Talbot, 1905). This work would be part of her dissertation, for which she would have the trilobite researcher Dr. Charles Emerson Beecher as a supervisor (Talbot, 1905).

Perhaps her most notable discovery, however, was that of the coelophysoid dinosaur Podokesaurus holyokensis. Dr. Talbot would discover the partial skeleton of this dinosaur encased in cracked bolder near the college in 1910, becoming the first woman to name a non-avian dinosaur species the following year (Talbot, 1911; Turner, Burek & Moody, 2010). Dr. Talbot would remark on the chance of the find in the American Journal of Science in June of 1911 (Albino, accessed March 8, 2015). She would name Podokesaurus from the greek word for swift-footed, referencing the name of the university for which she worked in the specific epithet (Talbot, 1911).

IMG_2158
Cast of the holotype of Podokesaurus on display at the Peabody Museum. Photo by the author, 2015.

Unfortunately, the skeleton of Dr. Talbot’s dinosaur would be destroyed in the 1916 fire that burned down Williston Hall (Albino, accessed March 8, 2015). Talbot would notably remark that she wished the specimen to go on exhibition at Yale or in Washington in the June 1911 issue of the American Journal of Science mentioned previously (Albino, accessed March 8, 2015). Nevertheless, Talbot was largely responsible for the growth of the Holyoke collection after the fire (Elder, 1982). She said to have been actively interested in the profession of paleontology to her death in 1950 (Elder, 1982).

Her contributions to paleontology in the eastern United States are invaluable. The specimen she discovered and described, though now destroyed, is one of the only skeletons of a dinosaur known from the east coast. She will forever remain the first woman to name one of the marvelous lizards.

For more on Podokesaurus, see this post.

References.

Elder E. 1982. Women in Early Geology. Journal of Geological Education 30(5): 287–293.

Talbot M. 1905. Revision of the New York Helderbergian crinoids. American Journal of Science (Series 4) 20(115): 17-34.

Talbot M. 1911. Podokesaurus holyokensis, a new dinosaur of the Connecticut Valley. American Journal of Science 31: 469-479

Turner S, Burek C & Moody RT. 2010. Forgotten women in an extinct Saurian ‘mans’ World. In Moody RT, Buffetaut E, Martill D, Naish D, eds: Dinosaurs and Other Extinct Saurians: A Historical Perspective. The Geological Society of London Special Publication 343: 111-153.

Albino D. Lost Dinosaur. URL:  http://www.mtholyoke.edu/~dalbino/books/lester/dinosaur.html. Accessed March 8, 2017.

 

 

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.

Thanksgiving My Oh My!

Thanksgiving My Oh My!

EDIT: I’ve added a link to my preprint on the Maryland theropod remains published this past summer. I’ve focused in a little more on some stuff now but I think it gives a good overview of what I’m focused on.

What a weekend this has been! I’ve finally been able to submit a big biogeography paper I’ve been working on for a while (started writing it last spring) and I have also managed to resubmit another revised manuscript. Sorry I haven’t been posting anything recently, but this year has been rather hectic in terms of research and traveling. Here’s a quick peak into what I’ve been up to.

Some highlights since I last blogged:

In August, I traveled to Dinosaur Ridge, located just outside the Colorado capital of Denver, to view the awe-inspiring trackways which line the sides of an old road which is now used as a bike trail. The large ornithopod tracks (which were mentioned to possibly made by the hadrosauroid Eolambia) and ornithomimosaur tracks were quite stunning. To my pleasant surprise, they also had a site from the Morrison Formation which held oh-so-pretty mahogany colored bones. The views of the red Morrison Formation rocks were absolutely stunning. Those rocks are of the same layer as those which cradle the famous Red Rocks Amphitheater.

The small museum at the Dinosaur Ridge main building was also a nice addition to the day. The people at Dinosaur Ridge have done a very good job of telling a story about the site in the context of the changing geography of North America during the Jurassic and Cretaceous. I especially admired their use of paleogeographic maps with displays on each period of time represented at Dinosaur Ridge in order to really give a greater perspective on the fossils. The displays also excelled at what I find some museums often do not. They gave not only a picture of the dinosaurs and other “cool” animals which lived at Dinosaur Ridge during each period in time, but also gave a picture of the entire environment. The murals by Michael Skrepnick were also lovely, and a life-size outdated Utahraptor sculpture was an amusing addition to the portion of the museum within the building.

Outside, a well-made life-sized Eolambia sculpture shadowed another little display of some Allosaurus bones. All in all, the museum was very good and I definitely recommend checking it out along with viewing the famous trackway.

Here are a few pictures of the museum, the main trackway on the ridge, and the views from Dinosaur Ridge.

IMG_1304.jpg
A friendly brachiosaur greets incoming visitors, while a rather murderous-looking Utahraptor peeks from  t new arrivals. Check out those cervicals. Eat your heart out, SV-POW!

 

IMG_1307.jpg

IMG_1313.jpg
The main track site.
IMG_1310.jpg
A closer view of the purported Eolambia tracks. The smaller tracks indicate a juvenile ornithopod walking alongside an adult.
IMG_1316.jpg
View from the ridge.

On September 18th, I had the honor of presenting some of my research on the paleobiogeography and paleoecology of Appalachian dinosaurs at a meeting for the New York Paleontological Society (NYPS). I heard a number of great talks during the meeting, including one on trilobites from the northeast and another on the formation of arches in rock.

The talk centered around research I’ve been doing for the paper I mentioned above which is centered on comparing dinosaur faunas from Appalachia with other faunas across the globe.

In October, I ventured to the AMNH to view some interesting theropod material from the Cretaceous of New Jersey. I don’t want to give too much away, but I hope to start writing a paper on the specimens I viewed pretty soon. Thank you to Carl Mehling for hosting me!

The weekend before thanksgiving, I was able to travel to Maryland to view some theropod material within the Dinosaur Park collections. The farmland and countryside around the Dinosaur Park site was very pretty. I’ve added a picture below of some of the farmland, which was a very nice treat before a long day of driving. IMG_2168.jpgThanks to Ben at Extinct Monsters for hosting me and showing me the collections. The preprint from this past summer can be found here.

 

I hope I’ll have some more time to blog soon, and thanks for bearing with me until now. I have a couple of ideas for what species I will feature for the next Antediluvian Beasts, so I’ll hopefully be able to write up an article. Happy Thanksgiving and thanks for reading!

 

 

 

Preprint Published: Ornithomimosaurs from the Arundel Formation

Hi everyone! I’ve been researching for a bunch of manuscripts all this past spring. Check out this new preprint on the ornithomimosaur materials from the Arundel Formation:

https://peerj.com/preprints/2308/

Additionally, I regard the Utah taxon Nedcolbertia justinhofmanni as an intermediate non-ornithomimid/deinocheirid ornithomimosaur. It shares a single flexor fossa on its pedal unguals and anteroposteriorly short phalanges from pedal digit IV with ornithomimosaurs (Brownstein, 2016) (listed as synapomorphies of the group by Choiniere, Foster & De Klerk (2012)). It also has metatarsals more elongate in form than tyrannosaurs and a proximally pinched metatarsal III.

What’s interesting to me is that the shape of metatarsal III of the Arundel form suggests that it had a more derived metatarsus condition than Nedcolbertia. I use this and a temporal comparison of the formations in which Nedcolbertia, the Arundel taxon, and what I believe to be its close relative (Kinnareemimus) to support my theory that ornithomimosaurs with different metatarsus conditions coexisted in North America (Brownstein, 2016). Unfortunately, the paucity of decent North American ornithomimosaur material from the Early Cretaceous of North America makes any analysis of possible ecological interactions between ornithomimosaur lineages ill-informed (Brownstein, 2016). It is interesting to note, however, that Nedcolbertia can be differentiated by many ornithomimosaurs by its manal morphology and simplistic and pneumatic dorsal vertebra (Kirkland et al., 1998).

All in all, the Arundel dinosaur fauna is in serious need of more research. If there’s any dinosaur researcher out there looking for something to study, the Early Cretaceous dinosaurs of Maryland are just another opportunity to be found in the eastern United States and Canada.

EDIT: Just fixed some reference formats and added a figure showing the metatarsals. Oh well. New version will be out soon.

References.

  1. Brownstein CD. 2016. Redescription of Arundel formation Ornithomimosaur material and a reinterpretation of Nedcolbertia justinhofmanni as an “Ostrich Dinosaur”: Biogeographic implications. PeerJ Preprints 4:e2308v1. 
  2. Choiniere JN, Forster CA & De Klerk WJ. 2012. New information on Nqwebasaurus thwazi, a coelurosaurian theropod from the Early Cretaceous Kirkwood Formation in South Africa. Journal of African Earth Sciences 71–72: 1–17.

  3. Kirkland JI, Whittle CH, Britt BB, Madsen S, Burge D. 1998. A Small Theropod from the Basal Cedar Mountain Formation (Lower Cretaceous, Barremian) of Eastern Utah. In Lucas SG, Kirkland JI & Estep JW, eds:Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin 14: 239-248.

Antediluvian Beasts of the East: Daeodon leidyanus

Antediluvian Beasts of the East: Daeodon leidyanus

Draining from the early Miocene Appalachian mountains are the streams and creeks which flow through the woodlands of New Jersey until they reach the blue Atlantic. Fed by mountain lakes and aquifers, these meandering waterways provide a much-needed source of liquid to the parched lowlands of the summer. Flowers and grasses shoot up through the cracked ground as the fluid product of the rainy season in the mountains turns the earth the deep brown and the tree leaves a healthier color. Though the temperature still peaks at over 32° Celsius (90° Fahrenheit), many large herbivores can be found in these coastal forests. Gigantic two-horned semiaquatic rhinoceros settle down into the waterholes of clearings. Three-toed horses race through the woods and munch on tree leaves as peccaries squabble over roots and burrow sites. Extinct distant relatives of modern mouse deer with two horns at the back of their skulls and a branching one at the front of their snouts compete for mates and territory, wearily checking the surrounding trees every few minutes for signs of danger. In the seas, multiple species of gargantuan sharks vie for chow with ancient relatives of sperm whales with gargantuan teeth an jaws as  other species of whales bask and play near the surface, their calls heard for miles. Mollusks scavenge on the sea floor as fish schools swim along.

Back on land, a group of peccaries jog through their favorite mud hole through an open patch of grass and flowers. The size of modern javelinas, these herbivorous mammals are often left to their devices by predators and other herbivores weary of sustaining an injury from the peccaries’ large front tusks. Even the rhinoceros, the largest animals to roam these forests, are weary of the smaller mammals. 

As the peccaries cross the opening in the forest unaware, a huge predator stalks them. The gleaming eyes of this colossus give off the faintest light on the predator’s distorted muzzle. Covered with scars, cuts and the occasional protuberance, it would appear that this creature is of another nature from the other mammals of early Miocene New Jersey. However, it is nonetheless the largest mammalian predator to stalk this forest. This is an entelodont, a relative of the group of mammals which includes hippopotami and whales. However, the grizzly, misleadingly hog-like appearance and terrifying predatory behavior of this odd mammal has given it the more ominous name of “terminator pig”. The massive front teeth of this humongous beast are rooted into its robust, meter-long skull. Its large body, built with powerful shoulder muscles and powerful, hoofed limbs to overpower its quarries, slopes down into a small tail tipped with fur. 

From the bushes, the terminator pig charges at the peccary group, which scatter in fear. However, the large carnivore has outplayed the smaller tusked mammals, and has snagged the belly of one peccary on its canines. As blood loss takes its toll, the panicked ensnared peccary tries at its large attacker with its front teeth, scraping the terminator pig’s chin. The counterattacks are of no help to the peccary, who soon dies in the jaws of the larger mammal. With a single bite, the entelodont devours a large portion of the peccary’s gut, though it will stash away the rest of its kill in a hole created by the roots of a fallen tree which the carnivore inhabits. 

Though the Miocene exposures of the east coast of the United States are more famous for their marine fossils, like those of the gigantic shark C. megalodon and the toothed whale Squalodon, a variety of equally incredible animals roamed the land. Unfortunately, these incredible animals, some of which among the largest predators North America would ever see, have not gotten the attention which they deserve.

One such carnivore, a mammal known as an entelodont, left its fossil mark in Farmingdale, New Jersey in the form of a left premolar and molar named Ammodon leidyanum by the famous paleontologist Othneil Charles Marsh (Marsh, 1893). Though another famous paleontologist, Edward Drinker Cope, speculated that the teeth came from a pig-like creature, more finds in the northwest United States would be needed to reveal the animal’s true identity (Gallagher, 1997).

In the end, the mystery of Marsh’s Ammodon leidyanum was solved. The mammal, now known to be an entelodont, was a large, gruesome predator with large teeth and the occasional bony protuberance off of its lower jaw to create a distinctive-looking skull. These big slashing teeth would have been able to rip into the flesh of the large mammals of early Miocene New Jersey, feeding the meat to the entelodont’s premolars and molars, which would start to grind and crush whatever the predator decided to swallow. Their long muzzles would have connected to a large, robust body supported by relatively thin, hoofed limbs. Among the classic features of the entelodonts were two bony lumps which extended from the skull.

More recent additions to the scientific literature had discussed whether Ammodon was truly a valid genus name for the Farmingdale entelodont teeth. In 1998, a remarkable conclusion as to the identity of the teeth was reached. It would seem that the teeth actually belong to a species of the western North American entelodont genus Daeodon, the largest known genus of entelodont (Lucas, Emry & Foss, 1998). Large individuals of this genus could have the shoulder height the height of a man. The holotype tooth of the Farmingdale creature is slightly larger and longer than the same element in western Daeodon (Lucas, Emry & Foss, 1998), which may suggest that the New Jersey animal was either larger than its relative from the American West or had larger teeth.

IMG_1636
The approximately one meter long skull of a western Daeodon at the Denver Museum of Nature and Science. Note the large front teeth. Photo by the author, 2014. 

The entelodonts as a group had evolved to pursue and attack the large mammals which benefited off of the plants of the plains and forests of North America, though they would occasionally chow on tubers and roots to supplement their primarily carnivorous diet. Like modern large mammalian predators, entelodonts were opportunistic, scavenging carcasses on occasion. In New Jersey, Daeodon leidyanum would have been a part of the Farmingdale local fauna of the basal Kirkwood Formation of coastal New Jersey (Tedford & Hunter, 1984; Gallagher et. al., 1995). This assemblage of mammals has yielded the remains of the three-toed horse Anchitherium, the rhinoceroses Diceratherium matutinum and Menoceras, the protoceratid Prosynthetoceras, and the peccary Hesperohyus antiquus (Tedford & Hunter, 1984; Gallagher, 1997), and is likely Arikareean in age (Lucas, Emry & Foss, 1998).

IMG_1635
Daeodon full body model at the Denver Museum of Nature and Science. Photo by the author, 2014. 

The relations of the entelodonts have been reflected on by many researchers, and in among the most recent additions to the literature, and the researchers involved found that the pig-like appearance of the entelodonts from which they get their popular nicknames (i.e., “terminator pig”) is rather misleading. Rather, the entelodonts seem to be more closely related to whales and hippopotami in a group termed the cetancodontamorpha (Spaulding, O’Leary & Gatesy, 2009).

In life, Daeodon leidyanum would have been a truly horrific sight as it hunted down fleeing mammals in the coastal forests of New Jersey. This ancient king of the forest was part of a great dynasty of carnivorous beasts which would only fall to extinction after many millions of years of success. Daeodon shows how wrong the belief is that extinction must mean some sort of evolutionary failure. Rather, the entelodonts were a success story, though like all species were unfit for some changing condition or conditions in their ecosystem, leaving only their devilish skulls and ancient skeletons behind for future creatures to observe.

IMG_0682
Daeodon leidyanus by the author. Pencils on paper, 2016. 

For more on large mammalian predators of the eastern United States, see:

Antediluvian Beasts of the East: Pliocyon robustus

References.

Marsh OC. 1893. Description of Miocene Mammalia. American Journal of Science 46(275): 407-412.

Gallagher WB. 1997. When Dinosaurs Roamed New Jersey. New Brunswick: Rutgers University Press. pp. 142.

Lucas SG, Emry RJ & Foss SE. 1998.Taxonomy and distribution of Daeodon, an Oligocene-Miocene entelodont (Mammalia: Artiodactyla) from North America. Proceedings of the Biological Society of Washington 111(2): 425-435.

Tedford RH & Hunter ME. 1984. Miocene marine-nonmarine correlations, Atlantic and Gulf Coastal Plains, North America. Paleogeography, Paleoclimatology, Paleoecology 47: 129-151.

Gallagher WB, Gilmore EJ, Parris DC, Grandstaff BS. 1995. Miocene mammals from the Kirkwood Formation of Monmouth County, N. J. In Baker JEB, ed: Contributions to the paleontology of New Jersey. Geological Association of New Jersey 12: 254-268.

Spaulding M, O’Leary MA & Gatesy J. 2009. Farke, AA ed. Relationships of Cetacea (Artiodactyla) Among Mammals: Increased Taxon Sampling Alters Interpretations of Key Fossils and Character Evolution. PLoS ONE 4(9): e7062.