Just what is Diplotomodon, anyway?

Hello there. Welcome to Diplotomodon. Pull up a seat and make yourself comfortable, because frankly, the one that I’m in is old, wobbly, and slightly broken.

This is all a bit weird, to be honest. I’ve entertained the idea of writing a blog numerous times before, but it never really came to fruition in any serious way. This time, though, it’s happening. It’s a very peculiar and interesting feeling. I assume the novelty will wear off shortly.

“I” in this instance am Kevin Sievers, and starting in the fall I’ll be attending Drexel University as an undergraduate student in order to pursue a degree in geoscience. It’s quite exciting, and I look forward to spending my next few years there. In the meantime, however, I’m stuck at home, and evidently I’ve decided that the best way to pass my time is to write a silly blog. Which is okay, I suppose.

aquarium artsy

This is me, at the Georgia Aquarium. There’ll be a writeup of my trip here in the near future.

Primarily, the posts here will be about paleontology, natural history, and similar topics. Don’t expect there to be a consistent schedule for posts – frankly, I can’t be bothered to put one together. If all goes as planned, I’ll be able to put a few up regularly enough to keep things fresh around here.

But I have one question left to answer (that I suspect is probably the most important one)…why have I decided to call this blog Diplotomodon? And for that matter, what the heck is a Diplotomodon, anyway?

Picking a proper name was difficult. The Internet monikers I’ve used in the past don’t lend themselves well to blog titles. As ever, I was leaning towards dinosaur genera as inspiration – and I wanted something that reflected the work of paleontology in New Jersey, my home state. But Dryptosaurus and Hadrosaurus didn’t really cut it, for a number of reasons. And it would probably get confusing if I decided at one point to talk about the creatures themselves. So I started looking at old, antiquated nomina dubia that were common in the Gilded Age of paleontology. Naturally, some were taken already. But then I came across Diplotomodon, and it seemed to be “the one”.

Leidy 1865 -Memoir on the extinct reptiles of the Cretaceous formations of the United States- Plate XX

Plate XX of Leidy (1865). The tooth of Tomodon is at bottom center (figs. 7-9).

In 1865, the eminent paleontologist Joseph Leidy described a single tooth found in the greensand deposits near Mullica Hill, New Jersey.* It measured about two inches in length, although the base was broken off and what remained was still somewhat damaged. Leidy named it Tomodon horrificus, meaning “dreadful cutting tooth”, and speculated that it may have belonged to a plesiosaur (Leidy 1865).

*Weishampel (2006) notes that the tooth probably originated from either the Navesink or Hornerstown Formation, both Maastrichtian-age beds.

It turns out, however, that the name Tomodon was already preoccupied by a genus of South American snake named twelve years earlier (Duméril & Bibron 1853). So in 1868, Leidy renamed his tooth Diplotomodon, and decided it was actually a type of fish (Leidy 1868). Personally I think this was a lazy way to go about things – Leidy basically stuck a word meaning “double” in the front of it and left it at that, rather than creating a new name that was actually descriptive of the tooth in question. But then again, this was a time when scientists created whole new taxonomic families based on a single scrap of bone, so maybe I shouldn’t bother questioning semantics from these people.


Tomodon dorsatus. Image by Diogo B. Provete, licensed under CC-BY-SA 2.5 (from Wikimedia Commons).

But the taxonomic turmoil was far from over. Over the next hundred years it was identified as a mosasaur (Miller 1955) or a theropod dinosaur (Cope 1870) (Welles 1952) on various occasions. Ralph Molnar (1990) and William Gallagher (1997) even went so far as to suggest that Diplotomodon was likely synonymous with the better known Dryptosaurus. Regardless, the tooth is apparently lost (Weishampel & Young 1996), so we couldn’t figure it out even if we wanted to.

Today, Diplotomodon is generally considered a nomen dubium (Holtz 2004), and nothing much is thought of it. One might hope that the tooth is rediscovered in an old museum cabinet, or that enough fossils of this creature are found to confirm its identity as a distinct species, but that’s wishful thinking at best. The ancient world has surprised us before, though…so never say never!


The only life restoration of Diplotomodon on the Internet, as far as I can tell. Image by Robinson Kunz, used with permission.

That’s the story behind Diplotomodon. Over the next few entries I’ll be writing about museum exhibits and events – I have some interesting stuff planned out. In the meantime, if there are any particular topics you’d like to see covered, feel free to leave a comment down below with your suggestions. If you have advice on how to operate WordPress leave that down below too. I still have no idea what I’m doing. I have no idea how to end blog posts, either. So there’s that.


  • Cope, E.D. (1870). Synopsis of the extinct Batrachia, Reptilia and Aves of North America. Transactions of the American Philosophical Society, New Series 14(1): 1-252 (link)
  • Dumeril, A.M.C., and Bibron, G. (1853). Prodrome de la classification des reptiles ophidiens. Mémoires de l’Académie des Sciences de l’Institut de France, 23: 399-536 (link)
  • Gallagher, W. B. (1997). When Dinosaurs Roamed New Jersey. New Brunswick, NJ: Rutgers University Press. p. 110
  • Holtz, T.R. (2004). “Tyrannosauroidea” In: D.B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria. Berkeley: University of California Press. pp 111-136
  • Leidy, J. (1865). Memoir on the extinct reptiles of the Cretaceous formations of the United States. Smithsonian Contribution to Knowledge. 14: 102-103 (link)
  • Leidy, J. (1868). Remarks on CONOSAURUS of Gibbes. Proceedings of the Academy of Natural Sciences of Philadelphia, 1868, 20: 200-202 (link)
  • Miller, H.W. (1955). A check-list of the Cretaceous and Tertiary vertebrates of New Jersey. Journal of Paleontology, 29(5): 903-914
  • Molnar, R. (1990). “Problematic Theropoda: “Carnosaurs”.” In Weishampel et al. (eds.), The Dinosauria. Berkeley: University of California Press. pp. 306-317
  • Weishampel, D.B. (2006). “Another look at the dinosaurs of the East Coast of North America”. III Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno, Salas de los Infantes, Burgos, Spain. Colectivo Arqueológico-Paleontológico Salense Actas, pp 129-168 (link)
  • Weishampel, D. B., and Young, L. (1996). Dinosaurs of the East Coast. Baltimore: Johns Hopkins University Press. 275 pp.
  • Welles, S. P. (1952). A review of the North American Cretaceous elasmosaurs. University of California Publications, Geological Science, 29: 47-143.