New Domes, New Interpretations

Thanks to Bob Sullivan, many of his co-authored publications from the New Mexico Museum of Natural History and Science (NMNHS) Bulletin are now available online (which you can find here). I talked about one of them, naming new oviraptorosaurs Ojoraptorsaurus boerei and Epichirostenotes curriei (Sullivan, Jasinski & van Tomme, 2011). The new papers recently made available include the descriptions of two new pachycephalosaurs, and comments on others. First, a frontoparietal from the Bayn Shire Formation (= “Baynshire Suite(Formation)”) of southern Mongolia is named Amtocephale gobiensis (Watabe, Tsogtbaatar & Sullivan, 2011). Second, a new species of Stegoceras, Stegoceras novomexicanum, is named from several specimens from the Fruitland and Kirtland Formations in the San Juan Basin of New Mexico (USA) (Jasinski & Sullivan, 2011).

When Flat-Head Met Dome-y

One of the most interesting aspects of ornithischian phylogeny has been (alongside whether heterodontosaurs are ornithopods or whatever) is the nature of many pachycephalosaur taxa. Recently, Schott et al. (2003) have done some great detective work in nailing down what they expect to be a firm argument for expected ontogeny in pachycephalosaurs.

Horns, Frills, Knobs and Domes – Morphological Ontogeny

Recently I’ve been embroiled in a discussion with various professional paleontologists, interested scientists, and lay paleophiles on the topic of the synonymy proposed by Scannella and Horner [1] for the Hell Creek chasmosaurine ceratopsians Triceratops and Torosaurus. I feel it necessary to place my thoughts here, as they are long and doing so in blog entries or on forums, etc., is getting tedious. I should have done this long ago, but attempts have failed because of the scattered nature of the individual parses I’d like to say about it. So, what I will do it summarize their hypotheses, then attempt a synthesis with my thoughts on the range of topics they argue about. It should be further notes that Horner and Goodwin [2] also recently proposed a similar synonymy of the Hell Creek pachycephalosaurids Pachycephalosaurus, Stygimoloch and Dracorex. I handled this latter paper in part in various places, most notably here and here, although I hope to endeavor better here

Sabre-Toothed Dinosaurs

And not one of them is a theropod. Oh, you’re thinking of Incisivosaurus gauthieri? It’s clearly a bunny-toothed dinosaur.

What follows is a discussion on one of my favorite topics: The dentition of Goyocephale lattimorei.