This week we will be checking out a unique looking early dinosaur with a very cool name. Meet Daemonosaurus chaoliodus!
Daemonosaurus was a small meat-eating dinosaur that lived in what is now New Mexico, United States, during the late Triassic period, roughly between 205 and 200 million years ago. From nose to tail it is estimated to have measured roughly between 5 to 7 feet (1.5-2.2m). These are estimates based on the fact that only the skull and neck were found. The genus name translates to "Demon Reptile" and the species name translates to "Prominent Tooth" in reference to its unusual front teeth.
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| Watercolor reconstruction of Daeomonosaurus by Christopher DiPiazza. |
The first thing you notice about Daemonosaurus is its unusual face. It possessed round, short-snouted skull with huge eye sockets, so it probably had sharp vision, possibly dark vision, in life. It possessed unusually long curved teeth right in the front of its mouth. In fact, the very frontmost teeth are the longest overall. The teeth themselves are mostly rounded in cross section with shallow serrations on the anterior sides only. It is difficult to exactly know what these extreme teeth were adapted for, but it was likely eating some form of meat. Perhaps it was a fish and other water prey specialist? Maybe it was snapping up small fast creatures, like insects? We may never know.
The identity of what kind of dinosaur Daemonosaurus is somewhat mysterious mostly because simply not that many dinosaurs from the Triassic period are known compared to other times. The Triassic was also a time when dinosaurs were still not clearly diversified into the more distinct forms we recognize from later times. Initially, when Daemonosaurus was first published on in 2011, it was identified as a theropod dinosaur, closely related to its contemporary, Coelophysis. This makes sense since they both had sharp curved teeth with serrations, and they even both possess a notch at the front of the upper jaw, which is a common train among early theropod dinosaurs. Later on in 2020, however, those same paleontologists who wrote the first paper identifying Daemonosaurus as a theropod, revised their stance based on more information, placing it just outside the theropod group as a kind of very early saurischian dinosaur, the broader group that contains both the bipedal theropods and the long-necked sauropods, closer to older dinosaurs, like Herrerasaurus. Since only Daemonosaurus' skull and neck have been found, we may still learn new things about it and its identity may change yet again in the future!
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| Photograph of all the fossil material that is currently known from Daemonosaurus. Note the long front teeth and huge eye socket. Photo featured in the 2011 paper by Seus et al. referenced below. |
When alive Daemonosaurus would have lived in a environment that swung between extreme aridness and heavy rain and flooding during the year. In fact, the bonebed it was found in is thought to be the result of a flash flood wiping out a bunch of animals. Daemonosaurus' most common neighbor appears to have been Coelophysis, of which it was surrounded by many skeletons of when it was discovered. It also would have coexisted with the early crocodilian, Hesperosuchus, and the giant predator Postosuchus, to name a few more.
References
Hans-Dieter Sues; Sterling J. Nesbitt; David S. Berman & Amy C. Henrici (2011). "A late-surviving basal theropod dinosaur from the latest Triassic of North America". Proceedings of the Royal Society B. 278 (1723): 3459–3464.
Nesbitt, Sterling J.; Sues, Hans-Dieter (3 August 2020). "The osteology of the early-diverging dinosaur Daemonosaurus chauliodus (Archosauria: Dinosauria) from the Coelophysis Quarry (Triassic: Rhaetian) of New Mexico and its relationships to other early dinosaurs". Zoological Journal of the Linnean Society. 191: 150–179.
Novas, Fernando E.; Agnolin, Federico L.; Ezcurra, Martín D.; Temp Müller, Rodrigo; Martinelli, Agustín G.; Langer, Max C. (2021-10-01). "Review of the fossil record of early dinosaurs from South America, and its phylogenetic implications". Journal of South American Earth Sciences. 110 103341.
