Earlier we talked about the Late Triassic saber-toothed dinosaur, Daemonosaurus (Sues et al. 2011, Fig. 1, CM 76821) originally considered a weird basal theropod between Eoraptor and Tawa. That’s due to taxon exclusion. The real sisters of Daemonosaurus were not tested. The authors also mistakenly nested Eoraptor within the Theropoda when it is actually an outgroup, a phytodinosaur closer to Sauropodomorpha, which were only included as a suprageneric taxon, along with Ornithischia. Unfortunately that’s the same suprageneric/taxon exclusion/inclusion problem that happens so often it’s not funny anymore.
Solution: add taxa and avoid suprageneric taxa
In the large reptile tree Daemonosaurus did not nest with theropods, but at the base of the Ornithischia between basal phytodinosaurs like Eoraptor and the basal ornithischian, Pisanosaurus. It’s been three years since that post.
Today Jeholosaurus (Han et al 2012) and Haya (Figs. 1,2), two widely acknowledged basal ornithischians, nest with Daemonosaurus. One look at the three of them together pretty much sums up the rest of this post. Note their chronology. This is a basal clade that lasted through all three periods of the Mesozoic.
That they nest together tells me the post-crania of Daemonosaurus likely had at least a proto-ornithischian pelvis and supports my earlier observation of a proto-predentary.
Fossils of Coelophysis were present on the same block that contained the skull of Daemonosaurus, Wonder if there was a predator/prey relationship? Skull lengths were similar. Overall size was likely similar too.
Han F-L, Barrett PM, Butler RJ and Xu X 2012. Postcranial anatomy of Jeholosaurus shangyuanensis (Dinosauria, Ornithischia) from the Lower Cretaceous Yixian Formation of China. Journal of Vertebrate Paleontology 32:1370-1395.
Makovicky PJ, Kilbourne BM, Sadleir RW and Norell MA 2011. A new basal ornithopod (Dinosauria, Ornithischia) from the Late Cretaceous of Mongolia. Journal of Vertebrate Paleontology 31: 626–640.
Sues H-D, Nesbitt SJ, Berman DS and Henrici AC 2011. A late-surviving basal theropod dinosaur from the latest Triassic of North America. Proceedings of the Royal Society B, published online
Xu, Wang and You, 2000. A primitive ornithopod from the Early Cretaceous Yixian Formation of Liaoning. Vertebrata PalAsiatica 38(4)318-325.