Science

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.

 

Advertisements

PaleoNews #22: Appalachian ceratopsians and more!

Hello and welcome to this shorter edition of PaleoNews. This spring, a few finds related to the landmass of Appalachia have been published on, and so here’s a look back at those.

NEW FINDINGS

Though the find was published on by the media this past summer (e.g., here), the first-ever record of a ceratopsid dinosaur from Appalachia has been published on in the journal PeerJ. In the paper “The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA)” (Farke and Phillips, 2017), the discovery of a single tooth from the Maastrichtian Owl Creek Formation is discussed in the context of the biogeography of horned dinosaurs in North America during the Cretaceous. The paper also discusses the Maastrichtian-age deposit that is the Owl Creek Formation and its fauna in some detail, as well as giving a brief overview of the dinosaur clades which inhabited the landmass of Appalachia (Farke and Phillips, 2017).

In the paper, the authors conclude that a dispersal event of ceratopsid dinosaurs occurred in North America as the Western Interior Seaway retreated during the Maastrichtian, the last stage of the Cretaceous period (Farke and Phillips, 2017). Thus, the tooth is both significant for being the first report of a ceratopsid dinosaur from eastern North America as well as for suggesting a possible dispersal event during the Maastrichtian.

IMG_2173.JPG

The MS find belonged to the ceratopsidae, as did Triceratops horridus (skull pictured above). 

I also had an article published on ornithomimosaur remains from the Arundel Clay of Maryland (Brownstein, 2017). The finds I describe are important for representing two distinct morphotypes (and thus possibly two distinct species) of ornithomimosaur that existed in the Arundel ecosystem. These dinosaurs would have coexisted with the titanosauriform sauropod Astrodon, the dromaeosaur Deinonychus, the carcharodontosaur Acrocanthosaurus, possibly the ornithopod Tenontosaurus, an indeterminate neoceratopsian, and the obscure nodosaurid Priconodon (e.g. Weishampel, 2006). There is certainly much more material to be published on from the Arundel Clay, so it should be exciting to see how the Arundel’s dinosaurs come to light.

IMG_2080.jpg

Two of the pedal unguals representing one of the morphotypes of ornithomimosaur present in the Arundel. 

FEATURED FOSSIL 

Today, I feature the skull of the Aurochs (Bos primigenius), an extinct species of large bovine that inhabited the wilds of Europe, northern Africa, and Asia during the Pleistocene and into the Holocene. Julius Caesar, in book 6 of his Commentarii de Bello Gallico, writes on the fantastic size and power of these animals (Commentarii de Bello Gallico 6.28). I highly recommend you read his description, either in translation or the original latin, if you haven’t already, as it gives a seldom-attained glimpse of an extinct animal of a great awe-inspiring nature.

IMG_3122.jpg

Overall, this has been a productive spring for Appalachian discoveries. Let’s hope for an even better summer! Thanks for reading.

References

Farke, A.A., and Phillips, G.E. 2017. The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA. PeerJ, 5:e3342. 

Brownstein, C.D. 2017. Description of Arundel Clay ornithomimosaur material and a reinterpretation of Nedcolbertia justinhofmanni as an “Ostrich Dinosaur”: biogeographic implicationsPeerJ, 5:e3110. 

Weishampel, D.B. 2006. Another look at the dinosaurs of the East Coast of North America, p. 129-168. In ‘Coletivo Arqueológico-Paleontológico Salense, (eds.), Actas III Jornadas Dinosaurios Entorno. Salas de los Infantes, Burgos, Spain.

 

Women in Paleontology: 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 they 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

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.

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. 

 

 

 

 

Antediluvian Beasts of the East: Carnufex carolinensis

A slight breeze blows the morning dew drops from the leaves of the plants surrounding the creek as a herd of herbivorous Coahomasuchus browse horsetails and ferns. These small armored reptiles are joined by a herd of large Gorgetosuchus, which bare magnificent spikes and ridges from their armored backs. These duck-billed armored herbivores or aetosaurs as they’re known are among the larger creatures to roam these forests, although they often fall prey to the many terrestrial and aquatic predators with which they coexist. 

Among such predators are phytosaurs, large, scaly hunters which bask along the banks of rivers waiting to snap at any passers-by. These cranky reptiles are hardly the devils of these forests , and often are frightened away by little but a scratch from one of the Gorgetosuchus’s shoulder spikes. Mobs of proterosuchids also line the water’s edge, but prefer fish and amphibians to the well-defended terrestrial herbivores. Often the aetosaurs must be more wary of the smaller but poisonous Uatchitodon, which scurry around in search of insects and small vertebrates to eat. When threatened, the small carnivores cower in a defensive posture. The small size of the Uatchitodon make them hard to spot, and often an aetosaur gains a scar from accidental confrontation with such small poisonous reptiles. 

Herds of large, cranky Placerias also pose a threat to the armored aetosaurs. The sparsely haired skulls of these cow-like herbivores bare large tusks that could easily cripple an ignorant aetosaur, and individuals from both Placerias and Gorgetosuchus herds bare evidence of confrontation with their large, herbivorous contemporaries. 

The aetosaurs’ greatest foe is an aged Carnufex bull. The old predator is a giant among the inhabitants of these woods, stretching 14 feet from nose to tail. He was once longer, but a chance encounter with a 3 meter subadult Carnufex caused the old bruiser to lose a small portion of the end of his tail. The old bull has a huge territory spanning almost six square miles, and has held the area for many years. The aetosaurs are easy prey for the aged reptile, who’s instinct gives away around the spiked herbivores’ armor. 

The aetosaurs, now finding themselves on a hill, start to chew through the vegetation covering the ground. Nearby is their silent enemy, the Carnufex bull, who hides behind a large boulder. The aetosaurs sense his presence, and as he appears from his bunker lower their bodies in defense. The gnarly scarred skin of the bull Carnufex gleams in the sun as he slowly creeps across the rocky soil in an austere manner, undaunted by the glimmering spikes of his targets. The bull suddenly erupts into a fury of predatory energy, latching onto the relatively unprotected head of one of the aetosaurs. His teeth sink into the aetosaurs face, blinding the poor herbivore. Disoriented, the herbivore stumbles while the other aetosaurs flee. The Carnufex bull now has the upper hand. Using his bodyweight, he pushes over the bloodied aetosaur, exposing its unprotected stomach. All the fleeing aetosaurs hear are the moans and growls of the combatants. Soon all falls silent, and another Triassic night sets in. 

Eastern North America has preserved an excellent record of the Late Triassic, with many formations bearing the remains of strange creatures of lineages long gone. Among those which contain the most complete record of this time is the Pekin Formation, which outcrops in the states of North Carolina. The Pekin Formation dates to approximately 231 million years ago, preserving some of the oldest known Triassic archosaur faunas in North America (Zanno et. al., 2015). Among the larger predators of this formation was Carnufex carolinensis, a relative of the ancestor of the group crocodylomorpha, which includes all modern day crocodylians and many other clades of extinct genera. Carnufex carolinensis would have been a large predator in life. The type specimen, a juvenile, would have already measured 3 meters long in life (Zanno et. al., 2015).

The most interesting thing about Carnufex carolinensis is not its size, but where as a predator it was in time. The Triassic provided an open door for evolution, as the Permian extinction had created unstable biological communities and altered ecosystems (Roopnarine et. al., 2007; Bambach, Bush & Erwin, 2007). New types of large predatory animals had room to grow.

IMG_3022

The skeleton of Prestosuchus, a large Triassic pseudosuchian. Pseudosuchians were among the groups which gave rise to large predators during the Triassic. Photo by the author, 2015. Note the phytosaur skull in the background.

What Carnufex carolinensis shows is that crocodylomorphs were more diverse during the Triassic than previously thought, and alongside early dinosaurs were diversifying to become both apex and non-apex predators (Zanno et. al., 2015). Carnufex carolinensis itself is the largest known terrestrial predator known from the Pekin Formation, and was much larger than the earliest known North American theropods (Zanno et. al., 2015).

Within the Pekin Formation, Carnufex carolinensis would have coexisted with both a variety of predatory and a variety of herbivorous animals. Bulky dicynodonts would have lumbered around next to the armored aetosaurs Gorgetosuchus, Coahomasuchus, and Lucasuchus (Green et. al., 2005; Heckert et. al., 2015; Heckert, 2012). Predatory animals like cynodonts and phytosaurs also inhabited the formation (Liu & Sues, 2010; Baird, 1986).

Carnufex represents a group of archosaurs responding to new opportunities in a recovering ecosystem. However, the large, terrestrial crocodylomorphs of the Triassic were not to last. The End Triassic Extinction would see the replacement of such large bodied forms by theropod dinosaurs (Zanno et. al., 2015). Carnufex and its contemporaries in the Pekin Formation ecosystem represent a bouncing back from extinction, a rise from oblivion.

IMG_0005 (1)

Carnufex carolinensis by the author. Pencils on paper, 2016. 

 

 

References 

  1. Zanno LE, Drymala S, Nesbitt SJ, Scheider VP. 2015.Early crocodylomorph increases top tier predator diversity during rise of dinosaurs. Scientific Reports 5: 9276.
  2. Roopnarine PD, Angielczyk KD, Wang SC, Hertog R. 2007. Trophic Network Models Explain Instability of Early Triassic Terrestrial Communities. Proceeding of the Royal Society of London B: Biological Sciences 274: 2077–2086.
  3. Bambach RK, Bush AM & Erwin DH. 2007. Autecology and the Filling of Ecospace: Key Metazoan Radiations. Palaeontology 50: 1–22.
  4. Green JL, Schneider VP, Schweitzer M, Clarke J. 2005. New evidence for non-Placerias Dicynodonts in the Late Triassic (Carnian-Norian) of North America. Journal of Vertebrate Paleontology Programs Abstracts 25: 65-66.
  5. Heckert AB, Schneider VP, Fraser NC, Webb RA. 2015. A New Aetosaur (Archosauria, Suchia) from the Upper Triassic Pekin Formation, Deep River Basin, North Carolina, U.S.A., and its Implications for Early Aetosaur Evolution. Journal of Vertebrate Paleontology 35: e881831.
  6. Heckert AB. 2012. Two New Aetosaurs (Reptilia: Archosauria) from the Upper Triassic Pekin Formation (Deep River Basin: Newark Supergroup) of North Carolina and the Phylogeny and Distribution of Aetosaurs. Geological Society of America Abstracts with Programs 44(7): 233.
  7. Liu J & Sues HD. 2010. Dentition and Tooth Replacement of Boreogomphodon (Cynodontia: Traversodontidae) from the Upper Triassic of North Carolina, U.S.A. Vertebrate Paleontology Asiatica 48: 169–184.
  8. Baird D. 1986. Some Upper Triassic Reptiles, Footprints and an Amphibian from New Jersey. The Mosasaur 3: 125-153.

Antediluvian Beasts of the East: Sauripterus taylori

Dust swirls through the water as a school of Bothriolepis fish hustle their way through the busy stream. Bothriolepis are the bullies of these waters, shoving off other fish using their bulky bodies and stabbing those which do not give them right of way with their sharp front fins. Bothriolepis are like tanks, the armored carapace which adorns the front of their body making the armored fish sink to the bottom of stream bed. 

These Bothriolepis belong to an ancient clade of fish called placoderms. Now, the group is extremely successful, but an extinction which soon shall exterminate a variety of creatures both flourishing in the seas and just colonizing land. Bothriolepis, though tyrannical in the way they treat the other fish of the stream, are little in this regard compared to their relatives in the open sea, wihch use giant body mouth plates to crush almost any prey animal they can find. Bothriolepis are also much more vulnerable than their cousins, as predators large enough to crush their protective armor still squeeze through the cramped waterways in which the placoderms live. 

The school of Bothriolepis swim through these busy waters for a purpose. Its breeding season for these fish, and both males and females are anxious to breed and escape back into the gloom of deep lagoons that jut into the land from the seemingly infinite greenish blue sea. The Bothriolepis are taking a risk, as their only predators in these waters prefer the large lakes where the armored fish go to breed. 

The school of armored fish arrives at their choice breeding spot. The Bothriolepis mate at the bottom of the lake, away from the watch of the wretched early tetrapods which line the banks to strike at sudden movement. These sluggish beats do well to wait on the banks, as they know bigger hunters occupy the water. 

On the side of the lake, ripples stirred by a the shadow in the water set the tetrapods galloping into the woods. The shadow, almost six feet long, is long and slender in shape. The figure does not yet spook the armored placoderms, who go on mating. Suddenly, a pair of Bothriolepis are sent flying out of the water, and the head of a massive fish bites off the unarmored abdomen and tail of the male fish, sending blood flying in all directions. The female, in shock, escapes the teeth of this monstrous predator. The hunter is a rhizodont, a type of large lobe-finned fish. The skin of this beastly fish is littered with scars, showing the age and stoicism of the predator. The rest of the Bothriolepis flee, but the giant rhizodont is still able to obtain two more meals. Once the armored fish are all gone, the rhizodont paddles back into the gloom of the lake, waiting for the memory of the attack to be forgotten and for new victims to enter its domain. 

Rhizodonts were giants among the Devonian fishes which pioneered the rivers and lakes of land. These fish are famous for their large size, with largest member of the group laying claim to the record of the largest known freshwater fish ever. However, some species included in the rhizodontida have evaded the interest of the public, including a species named Sauripterus taylori which swam through the lakes and rivers of the Northeastern United States over 300 million years ago.

Sauripterus taylori is known from a couple different specimens, all retrieved from the Catskill Formation of Pennsylvania. The Catskill Formation is a mostly terrestrial deposit, and was set down in the Late Devonian during a time known as the Famennian (Davis & Shubin, 2004). In the ecosystem the Catskill represents, Sauripterus would have swam alongside fish like the armored placoderm Bothriolepis (Stein, 2002). Along the shores of the lakes and rivers the rhizodonts inhabited, plants like Euphyllophytina would soak up sunlight (Stein, 2002). Remains of possible juvenile Sauripterus have also been unearthed from the famous Red Hill locality in Pennsylvania, where the large fishes would have coexisted with both tetrapods like Hynerpeton bassetti (Shubin, 2009) and the famously giant fish Hyneria lindae (Daeschler et. al., 2007).  

The fossils known of Sauripterus taylori provide key information on the structure of rhizodontid fins. The original specimen consisted of fragments of the animal’s head, scales, vertebrae, and a well-preserved right pectoral fin (Broom, 1913). More recently, another well-preserved right pectoral fin has been described (Davis & Shubin, 2004), suggesting that the pectoral fins of Sauripterus were well-adapted for propelling the large fish through the water and pushing the animal from the bottom of the lakes and rivers in which it inhabited. The limbs of Sauripterus would have allowed it to be both gigantic and powerful, enabling it to hunt both swift and slow-moving armored prey within the waterways of Devonian Pennsylvania.

Broom, 1913 suggested the original right pectoral fin specimen of Sauripterus taylori to be nearly identical to the ancestral tetrapod limb morphology. However, it has recently been found that the similarities of the limbs of early tetrapods and rhizodonts are a case of independently evolved traits (Davis & Shubin, 2004).

Sauripterus would have been an incredible predator in life. Its large size combined with its agility would have made the fish quite an imposing predator. Like in other rhizodonts, fangs and large tusks would have peeked from the front of the jaws of Sauripterus, sinking into the flesh of fish like fishing hooks. A powerful bite would have aided the large lobe-finned fish in attacking prey. Though we known little about this ancient predator, further excavations at sites like Red Hill may result in the discovery of better specimens, revealing a hunter long forgotten among the Devonian rocks of the Eastern United States.

IMG_0819.jpg

Sauripterus taylori by the author. Pencils on paper, 2016.

 

Happy Earth Day! To read the last Antediluvian Beasts of the East installment, click the link below:

Antediluvian Beasts of the East: Dryptosaurus aquilunguis

 

 

References

  1. Davis MC & Shubin NI. 2004. A new specimen of Sauripterus taylori (Sarcopterygii; Osteichthyes) from the Famennian Catskill Formation of North America. Journal of Vertebrate Paleontology 24(1):26-40.
  2. Stein WE. 2002. SUNY-Binghamton Paleobiology Collection. URL: fossilworks.org/bridge.pl?a=collectionSearch&collection_no=28211 . Accessed April 13, 2016.
  3. Daeschler EB, Shubin NH .2007. New data on Hyneria lindae (Sarcopterygii, Tristichopteridae) from the Late Devonian of Pennsylvania, USA. Journal of Vertebrate Paleontology 27(S3): 65A.
  4. Shubin N. 2009. Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body. New York: Vintage. pp. 13. 
  5. Broom. 1913. On the Origin of the Cheiropterygium. Bulletin of the American Museum of Natural History 32: 459-464.