Subsequent to my post on Nick Longrich and colleagues proposed new taxonomy for an old oviraptorosaur, there has been some interest about some other oviraptorosaurs, and I felt it would be useful to write up a little post about those things. First off, though, it should be noted that several of these taxa are worthy of their own subjects, but that one of them, which involves the recently-published (and now “legit”) Yulong mini, requires publication of another “illegitimate” species to be formally published[n1].
(Just by me putting up that “[n1]” you will know that I am about to clash with the “legitimate-illegitimate” publication debate, and probably Mike Taylor.)
Mickey Mortimer followed very shortly my post by discussing specifically the issues surrounded Longrich’s phylogenetic analysis, which stems from his modification of the issue-laden
Maryańska Osmólska et al. (2004) analysis from The Dinosauria (2nd Ed.). Mickey’s analysis also touches on some things noted in this paper, specifically variation among the metatarsals and tarsometatarsi, and it’s all well-worth a look. Frankly, it is not apparent to us that much which is published conclusively separates so-called “elmisaurid” and “caenagnathid” pes types, and what differences exist might merely be ontogenetic or variable within groups. The conclusion generally can be: Degrees of fusion are not settled in most dinosaur groups when it comes to either age or sex, so deciding something final when one is dealing with a grand total of four nearly complete metatarsi is questionable.
It is important to re-iterate this point: “Leptorhynchos” is not a legitimately published name; I am informed by Nick Longrich this error will be rectified. Until then, use of this name, including on its new Wikipedia entry — which avoids mention of this point — is improper.
On the Dinosaur Mailing List, Evelyn Sobieski returned me to a topic I’ve been waiting to investigate further, the subject of UCMP 143274, the so-called Cretaceous “parrot.” This specimen is important for various reasons, and ever since Dr. Thomas Stidham originally described this specimen, it has fallen somewhat by the wayside: Drs. Gareth Dyke and Gerald Mayr (1999) argued that the identification of “parrot” was essentially incorrect, whilst Dr. Sylvia Hope (2002) suggested that Stidham might have a point.
Dyke and Mayr specifically compared the specimen positively to caenagnathid jaws from the Late Cretaceous of Canada, an allusion that has borne some positive fruit in comparison. It is difficult not to be enticed by the idea, but several aspects of it require analysis. Preliminary investigation suggests that even if the specimen were to be a caenagnathid, it would be a particularly unique one, and it is not clear if the differences are phylogenetic, or ontogenetic, or based on convergence. My response to Evelyn says as much. For the sake of exploration, an investigation into the variety of bird jaws out there, especially primitive ones, underscored Dyke and Mayr’s argument that it is incomparable to even basal psittaciform lineages, and that extending crown parrot jaw morphology nearly through the entire Cenozoic borders of the silly, given basal psittaciform jaws look nothing like the crown. Some birds have similar jaw shapes, but only if you take ONLY the symphyseal region into account (e.g., procellariiform birds, like gulls or albatrosses), yet there are massive differences (they are not thin as an eggshell, and have a deep symphysis with a broad caudal groove for neurovascular invagination, which in parrots and this specimen enter the bone dorsally. But that condition may merely be based on the thinness of the bone; it shouldn’t be necessarily phylogenetic.
I have set myself the goal of using UCMP 143274 as the flashpoint for assessing caenagnathid jaw evolution, as I feel it necessary to consider that specimen in specific to determine whether an observation I’ve made (which I will not voice aloud) can be corroborated. If this bears fruit, either to dismiss or confirm my observation, I will then push forward on discussing potential variation in caenagnathid jaws, and their relevance to Oviraptoridae. It is to this point also that my eventual discussion on Yulong mini and an unpublished ([n1] again!) oviraptorosaur will turn. When these things are mentioned, you will understand these cryptic statements, but at the least I should say that Oviraptor philoceratops is not the loneliest oviraptorid. This year, I hope to get to SVP as it will be the “short” trip of traveling from Portland, Oregon down to Los Angeles, CA (city of my birth) and then a mere short trip up north to Berkeley, where UCMP 143274 is housed. Curators willing, I should be able to photograph the **** out of it and get some answers regarding my hypotheses about it.
Caenagnathidae represents a challenge, I think one that few are willing to admit exists, that it seems to house potentially more variation than is implied by other groups of oviraptorosaurs. Jaw morphology seems to grade along a diverse of shallow and deep jaws, blunt-ended or pointy, and with all manner of grooves and knobs on the dorsal surfaces of the symphyseal surfaces. To date, no attempts have been made to place these into an evolutionary framework, or even an ecological one, and explore their relationship to phylogenetics. Longrich et al. (2013) explored some aspects of these, but haven’t expanded this into a broader, even morphometric, model with any consideration towards the implciation that each jaw might be evolutionarily novel. We are natural lumpers, in many cases, grouping things together to like similarity, whilst excluding others without “enough” similarity. A more synthetic system should be employed, rather than assumptions of broad similarity or its eventual recourse to synonymy of taxa or referral of odd specimens into neat, narrow containers.
[n1] My general philosophy on the issue is that if the journal distinguishes a pre-print form as NOT PUBLISHED, especially when concerning taxonomic nomenclature, it is NOT WISE to then pretend that publication is a valid form. This requires more excessive bookkeeping than necessary. Thus, only the formal, final publication (the paper one, in some cases) is the valid one, as it is that data from which taxonomic nomenclature depends. In an era where digital publication is becoming extremely popular, and several digital-only journals are developing which produce taxonomic nomenclature, I wish this weren’t the case: The paper is available in nearly its final form by the time it goes up on the journal or distributor website(s), so is “available” for perusal and discussion, yet the nomenclature is “not available” until a later — often months later, which can pass the year mark — date. In the case of Lü et al., 2013, the paper was accepted in its essentially final form in early December, 2012, then placed online one month later, in 2013, but not published in print until February, 2013. Whilst this creates an effective difference of only one month, this can become tricky when potential synonyms become involved. It is best, I think, that should journals create this dichotomy of timing, that taxonomy-containing papers be excluded from pre-print options unless they are in online-only journals. There is no conflict at this point.
Dyke, G.J. & Mayr, G. 1999. Did parrots exist in the Cretaceous period?. Nature 399: 317-318.
Hope, S. J. 2002. The Mesozoic radiation of birds. pp.339-388 in Chiappe and Witmer (eds.) Mesozoic Birds: Above the Heads of Dinosaurs. University of California Press, Berkeley and Los Angeles.
Longrich, N. R., Barnes, K., Clark, S. & Millar, L. 2013. Caenagnathidae from the Upper Campanian Aguja Formation of west Texas, and a revision of the Caenagnathinae. Bulletin of the Peabody Museum of Natural History 54 (1): 23-49.
Lü J.-c., Currie, P. J., Xu L., Zhang X.-l., Pu H.-y. & Jia S.-h. 2013. Chicken-sized oviraptorid dinosaurs from central China and their ontogenetic implications. Naturwissenschaften 100 (2): 165-175.
Osmólska, H., Currrie, P. J. & Barsbold R. 2004. Oviraptorosauria. pp.165-183 in Weishampel, Dodson & Osmólska (eds.) The Dinosauria, 2nd Edition. University of California Press, Berkeley.
Stidham T. 1998. A lower jaw from a Cretaceous parrot. Nature 396: 29-30.