The “Mitrata” Oviraptorid

There are a few images floating around of a set of skulls of an hitherto undescribed oviraptorid, one with a tall, steepled premaxillo-nasal crest. This one’s been around for a while, though. Gaston Design has casts of them, one is definately in private hands, and one is certainly in an institution. But there’s more to it than that. Luis Rey illustrated it for his book, A Field Guide to Dinosaurs: The Essential Handbook for Travelers in the Mesozoic (Gee & Rey, 2003; see ref below), wherein he grants a species the name “Ronaldoraptor” (pg.134). This was meant intentionally to be not for permanent taxonomic purposes, and so we don’t pretend that this is a nomen nudum at all. But what Luis illustrated does exist, and I mentioned it not that long ago when discussing one of those privately-held specimens.

Specimens of the “mitrata” oviraptorid … or oviraptorids. It’s actually not quite that clear. The first is found from Ask.com on Oviraptor (of philoceratops fame, which is most certainly isn’t) while the other comes from Witmer Labs site.  The one on the right is a cast, but the one on the left may be the original or a cast (the sheen implies the latter). Specimens are not to scale.

There is good reason to suspect this is a new taxon, with the shape of the antorbital fossa being one such thing, as well as the form of the crest, though it is not quite clear what ontogeny may play in this. Both have a sloped quadrate and 90° ascending ramus of the jugal to the ventral margin (which is here shown horizontal for the sake of a baseline), and both of these features are considered autapomorphic of Citipati osmolskae (Clark et al., 2000). I’ve taken to calling this form “Mitrata,” as seen here:

The front half of the skulls of virtually all “relevant” oviraptorosaurs. “Mitrata” is labeled “F.” There’s more than a little bit of undescribed stuff going on in this image. Maybe I’ll talk more about the two species of Caudipteryx sometime.

You’ll note at first that the skull (labeled “F”) is smaller than that of Citipati osmolskae (labeled “G”), based on MPC-D 100/978. This illustration is based on the image above and at left (from here), rather than at right (from here) because, at the time, it was done from a substantially better photograph than was available than the one up top at right, as well as based on a photo of the actual skull, not what seems to be a cast. Nonetheless, the distinction here is that the skull’s cranial crest is larger, the antorbital fossa is elongate and low rather than tall and triangular, and there’s something funny going on with the fossae around the external naris. The skull up top at right shows that the external naris is ovate and teardrop-shaped, as in Citipati osmolskae, so this is also another point of similarity.

So “Mitrata” represents what is probably a new taxon, although what to call it is likely to be debatable. It’s likely a close relative of Citipati osmolskae, and this will likely result in someone naming it as a new species of the clade Citipati (or in the parlance of many taxonomists, a species of that genus). Edit: It should have been noted in this section why I call the thing “Mitrata” (which, like “Big Beak,” is a placeholder monicker). This alludes to the word “miter” (or “mitre”) and its root mitra (a Greek word borrowed by the Romans for the headdress of a Jewish high priest — kippo or kippah — and resembling the Shinto eboshi). It would literally mean “having a [priest’s] hat.”

“Ronaldoraptor” deserves an extra sort of rib, as it were. First, note that it is not the name of a taxon being proposed in seriousness, and thus is not intended to actually be for a permanent, scientific record. Gee and Rey actually created a few “taxa” for the book in which they desire to create a “field guide” of sorts, whereupon a false ecology may be explored in more detail than is known. So all encountered forms are granted names. While the name is meant in the style of formal taxonomy, it is not actually taxonomy in any sense that is usable. But you might see it somewhere, largely in the sense of this skull.

It’s also named for this guy:

Check out the hair. Yeah, that’s why.

That’s Portuguese footballer Christiano Ronaldo dos Santos Aveiro, or just Ronaldo — like fellow footballer Pelé, who needs any more of a name? — and he’s pretty famous on the football thing (you know, real football, not that “pansy” armor-wearing thing we Americans do, what Americans try to call “soccer,” but not to these guys’ faces). If I were even slightly tempted to formally name this (and I’m not) I’d want to keep on trucking with Rey’s suggested name just because of the hair. But, I’m not. Just want to make that clear.

Clark, J. M., Norell, M. A. & Barsbold R. 2001. Two new oviraptorids (Theropoda: Oviraptorosauria) Late Cretaceous Djadoktha Formation, Ukhaa Tolgod, Mongolia. Journal of Vertebrate Paleontology 21(1):209–213.
Clark, J. M., Norell, M. A. & Rowe, T. 2002. Cranial anatomy of Citipati osmolskae (Theropoda, Oviraptorosauria), and a reinterpretation of the holotype of Oviraptor philoceratops. American Museum Novitates 3364:1-24.
Gee, H. & Rey, L. V. 2003. A Field Guide to Dinosaurs: The Essential Handbook for Travelers in the Mesozoic. Barron’s Educational Series, Inc.