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.


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).


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.


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


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. 





Scans, glorious scans

Hi everyone. I’ve been working on the book and research has led me to Donald Baird’s 1989 paper “Medial Cretaceous carnivorous dinosaur and footprints from New Jersey” which was published in the journal Mosasaur. If anyone has a scan of the paper or of the figures of the footprints included within the paper, it would be really helpful if you could share them with me. Thanks!


Baird, D. 1989. “Medial Cretaceous carnivorous dinosaur and footprints from New Jersey.” Mosasaur 4: 53-63.

It’s Time For a Change

Hello everyone! I feel badly that I have not been blogging as actively for around a month now, but with the start of every academic year things go nuts (as we all know). I can, however, tell you all that some awesome stuff was found over the summer, and will be highlighted very soon…

Secondly, it is Autumn as of this past Wednesday, and since I am starting to hate the look of this blog, some stylistic changes will be put into place. I want the blog to really pop out and stun the reader!

That’s all for now. Thanks for reading!

A Quick Post for Preservation

Hello all. I’d quickly like to mention that a friend of mine, Billy Doran, who helped with the excavation of some specimens this summer, is starting a project centered around the preservation of a site Billy calls “Dinosaur Junction” which is located in Walcott. The site preserves body and trace fossils from all three periods of the Mesozoic era, hence the name. The tracks are very impressive, and are also very large. Certainly this site deserves to be recognized and protected, right?

Billy has started to do just that. He has started to spread the news and hold fundraisers, and he would love it if you spread the news as well. Billy is still trying to figure out how to reach an agreement with the BLM (as the site is on BLM land) to create a program around this site. Here are some photos of the site and the fossils found there:




For more information, contact Billy at: 


Thanks again everyone for reading, and hopefully this project will quickly advance, securing the preservation of these fossils.

A response to The Tetrapod Zoology Podcast #45: Why Lambeosaurines did, in fact, persist into the Maastrichtian

Recently episode #45 of the acclaimed Tetrapod Zoology Podcast was released, and, as usual, I found time to listen to it while illustrating for the Appalachia book. One point made by Darren Naish, however, caught my ear. While illustrating a point on the decline of the decadently frilled ceratopsians and crested lambeosaurines, he suggested that none of them persisted to the Late Maastrichtian. That might be true for the former of the two dinosaur groups, but the latter still hung to life in the-you-know-what continent. That’s right, Maastrichtian lambeosaurine bones have been found in deposits from Appalachia. Let me elaborate…

While in the west crestless forms like Edmontosaurus were almost the only surviving genera of the hadrosaurid lineage, the eastern shores of the newly-formed North American continent seem to still have supported the crested magnificence of the lambeosaurine hadrosaurs.

Edmontosaurus, everyone's  (except for me!) favorite Maastrichtian hadrosaur in all its glory. Photo by the author, 2014.

Edmontosaurus, everyone’s (except for me!) favorite Maastrichtian hadrosaur in all its glory. Photo by the author, 2014.

Indeterminate remains of a lambeosaurine have been reported from the Navesink Formation of New Jersey not only from one, but two localities. The Navesink Formation itself is a Maastrichtian deposit dating from around 70-66 million years ago. Gallagher (1993) reported indeterminate lambeosaurine remains from the West Jersey Marl Company’s Pit, Barnsboro, New Jersey, and Gallagher (2002) reported of indeterminate lambeosaurine remains from the Inversand Company marl pit locality in Gloucester County, New Jersey. It certainly seems a lambeosaurine was present in the Navesink ecosystem.

This is the partial leg of a juvenile Corythosaurus casuarius, a lambeosaurine dinosaur. Photo by the author, 2015.

This is the partial leg of a juvenile Corythosaurus casuarius, a lambeosaurine dinosaur. This specimen was collected in South Dakota. Photo by the author, 2015.

Lambeosaurine remains have also been reported from elsewhere on Appalachia. Rich et. al. (1997) reported Lambeosaurine remains from the Maastrichtian of the Kanguk Formation. The occurrence of lambeosaurine remains in the Kanguk Formation not only has implications for the survival of lambeosaurines into the Maastrichtian, but also for the presence of possible “polar dinosaurs” in eastern North America.

It seems as though as they declined in the west, lambeosaurines still thrived in the east up until the very end of the Mesozoic.

Although I am being nitpicky with this short write-up, my goal is to emphasize the importance of research before stating scientific claims. I don’t mean to offend either Darren or John, but I wanted to catch this little sliver of misinformation.


1. Gallagher, W. B. 1993. “The Cretaceous/Tertiary mass extinction event in the North Atlantic coastal plain.” The Mosasaur 5:75-154.

2. Gallagher, W. B. 2002. “Faunal changes across the Cretaceous-Tertiary (K-T) boundary in the Atlantic coastal plain of New Jersey: restructuring the marine community after the K-T mass-extinction event.” Catastrophic Events and Mass Extinctions: Impacts and beyond. GSA Special Paper 356:291-301.

3. Rich, T. H.; Gangloff, R. A.: Hammer. W. R. 1997. “Polar dinosaurs.” In P. J. Currie & K. Padian (eds.) Encyclopedia of Dinosaurs. San Diego: Academic Press. pp. 562-573.

Time for some Geology!

Apart from the collecting I’ve done so far in Colorado (which, by the way, has turned up really nothing good), I have also gotten to witness some really interesting Rock Mountain geology. Here are a few highlights:

1. Beaver Lake

This lake, formed by glaciers and fed by snowfields, is situated above the resort town of Beaver Creek, and is home to trout and, of course, beavers, among other things. So far, my ventures have taken me to the lake twice, the first ascent more pleasant then the second, in which I was subject to two thunderstorms. Here are a couple pictures: IMG_4988


I’ve also managed to witness some pretty beautiful sunsets and their affect on the color of the Gore range. Some peaks in the range rise to more then 13,000 feet above sea level, but all are under 14,000 feet. I managed to snap the pictures below during what became a very, very pretty evening.


IMG_5082Finally, check out Cross Creek, a small waterway which, this year, rose to a point where I was scared to cross the bridge above it, lest I be washed away in the white water rapids!

IMG_4828That’s all for now, but stay tuned for more updates on the book and on the collecting trips. Thanks for reading!

I’m Writing a Book

I was going going to make myself write one sometime, so why not now?

A few months ago, I got the idea to write a book about the prehistoric landmass called Appalachia. This is actually what inspired me to do Antediluvian Beasts of the East. You might be asking why I haven’t shared this earlier. Well, I just didn’t know if I would write a book until around 3 months ago. Dave Hone’s post also gave me confidence to announce this.

So far, the working title is Appalachia Prehistorica, although I doubt that will stay. If you have any suggestions on a title, feel free to comment below. I’ll be giving updates on this blog periodically. Let’s hope it goes well.

A Few Words on David Raup

As I’m sure some of you know, the first president of the Paleontological Society, passed away today at the age of 82. In remembrance, I’d like to share how his work helped me to become interested in the isolation and extinction of the paleofauna of Appalachia.

Some time ago, I read a little of his work on extinction patterns. Although I didn’t (and still don’t) agree with some of his theorems, his work got me interested in the gradual decline of species. His work opened me up to papers on extinction. Eventually, I stumbled upon one or two papers documenting the K-T extinction event on Appalachia, and I was hooked. Thank you, David Raup, for helping to position me down the road I have taken to this day. You will be missed.

My condolences go out to his family and friends during this sad time. If you have a story about Mr. Raup, please feel free to comment below.

It’s That Time of Year Again…

For much of the world, the middle of summer is approaching. For me, that means the most stressful, restless time of year outside of publishing a paper. That’s right, it’s fossil huntin’ season!

Earlier today, I went scouting for invertebrate fossil fragments. The fossils I was looking for are from the Minturn Formation, a carboniferous layer of brown-to-tan colored rock. Outcrops appear all over Vail valley, and so its not hard to find where to start looking. Unfortunately for me, today was pretty unproductive. Right now it’s 11:40 AM and I’ve had to pull out of the collection zone, as thunderstorms have just blanketed the valley.  Vail pass is completely overcast from what I can see, with clouds rolling into the Gore range. Thunderstorms in the Rockies are annoying, but pretty. I also just had some bad luck today when it came to the fossils I’ve found. A piece of coral and a couple fragments of invertebrate carapace are all I can say I’ve collected.

Hopefully tomorrow’s weather will allow for collecting conditions, but if not, it’ll be another day of research. If the weather really stinks, I’ll probably head to town or something. Oh well!