Oviraptorosaur Project Summary


I am (unfortunately) a published author. The reason I say “unfortunate” here is that of the two scientific things I’ve written that have been published, they were abstracts only and were published in a proceedings volume for two different events which I did not attend. Without a presentation, I am loath to present these works as valid of anything: An abstract is, in many cases, a suggestion and a hit of something else, or a condensation of what the main work contains; in the case of the latter, it is a conclusion, before the main remarks. In my case, It was the former type: suggestions, with little substance.

Here, I would like to discuss the topic of both of these abstracts, and what I really intended for them.


The first is [1] (Headden, J. A. 2001. Jaw function in Oviraptoridae (Dinosauria: Theropoda). Society of Vertebrate Paleontology, Abstracts. Journal of Vertebrate Paleontology 22(supp. to 3):59A.):

Jaw function has only been briefly assessed in oviraptorid theropods, focused primarily on the net force executable by the jaws during the action of the bite. These analyses have only considered the relative strength of the jaws to function, and have not considered an analysis of function except relating to strength of the jaws.
Oviraptorids are a novel group characterized by shortened jaws and hypertrophied palatal bones, and edentulousness with remarkable form of the lateral occlusal bones (maxilla, premaxilla, and dentary). A mechanical analysis demonstrates a distinctive jaw function, and suggests novel oral anatomy not preserved in theropods: 1) propaliny, 2) reorientation of the throat cavity below the jaw, rather than behind it, 3) expanded and derived palate adapted for crushing. Carnivory in the classic sense is not ruled out.
Historical comparison with dicynodont synapsids is not ruled out, either, and is further comparable in the form and function of the testudinine jaw. Novel adaptation of the jaw relating to feeding style include: convex articular contact with the quadrate; edentulousness; the secondary bony palate is modified into a rasp-like surface; widening of the jaws; shortening of the skull and anterior displacement of the jaw flexor and adductor musculature; throat displaced ventrally; expansion of fenestra so the jaw is lightened and the skull forms a box composed primarily of rods and narrow plates; fusion of the symphysis.

The second is [2] (Headden, J. 2002. Henry Fairfield Osborn and revising the Oviraptor myth. Society of Vertebrate Paleontology, Abstracts. Journal of Vertebrate Paleontology 22(supp. to 3):59A.)

The early 1920s brought the discovery of new fossils from southern Mongolia by expeditions from the American Museum of Natural History. Among these included a toothless theropod lying near a nest of eggs, in a “grasping” posture; initially, it was assumed that the eggs belonged to Protoceratops andrewsi by the relative abundance of Protoceratops and the nests versus the single specimen of Oviraptor philoceratops, and that the theropod was therefore a predator upon the eggs. Osborn, to whom fell the task of describing most of these fossils, even identified several corroboratory [sic] features of the jaw, including a ventral process of the palate (misidentified from a partial ectopterygoid) in the holotype, that were used to support an egg-eating lifestyle. Field work in northern China and in southern Mongolia in the 1980s and 1990s up to now have produced numerous nests of the “Protoceratops” type in association with overlying, “brooding” specimens of various oviraptorids; these eggs have been shown to contain at least one embryo of an oviraptorid, rather than a ceratopsian, and indicate the affinity of the nests was originally erroneously assumed. The recent work has led to the creation of an idea that Oviraptor was not an egg-”thief” but an egg-”mother”, tendering Osborn[‘]’s theory as an antiquated notion ill-suited to current understanding.
Jaw anatomy in oviraptorids shows the development of several features that indicate dietary specialization to crushing, including an expanded secondary body palate, enlargement of the temporal musculature, and a palatal design that enhances the holding, puncturing, pulverization, and swallowing of an egg or its contents. This indicates that oviraptorids in general may have likely incorporated eggs into their diet often enough to lead to selection favoring this food: other foodstuffs would have been secondary to the eating of an egg. This does not contradict that oviraptorids were good mothers, and they may have preyed upon the eggs of other dinosaurs, of which the Mongolian Late Cretaceous had in abundance.

(Note the discrepancy in the name: I have a middle initial, but it’s included only on the first citation, which I think is my fault during submission; also, note the page numbers, which could have been otherwise as the SVP has begun picking up on presentations, increasing the number of people with A-H names presenting.)

The first issue that arises from this is whether these are legitimate publications; and the answer to that question (from me) is “No.” I do not cite them, and I do not tell other people that I have publications to my name, as it seems ego-stroking. The second is that the first is poorly, very poorly written; I was much better on the second, but imagine the presentation! You are lucky to have missed this if I’d attended. The third issue is that I do not say much here at all, meaning what’s in these cannot really be used to say much. But there is more to say, and I would stand by what I’ve written in them.

So is there more to these? I was in the process of producing posters for both and an oral presentation for the first, when the data was lost with the first of several computer crashes. I don’t even have the figures anymore. Fortunately, I still remember what I would have said, and this is what you’ve been slowly reading on my series on diet in oviraptorosaurs. I still want to do more, much more, that prevents too much depth on these, but require some good academic work and access to university and museum resources I simply lack. Moreover, these remind me that I want to get into school, so that I can learn more to expand what I have seen.

These abstracts reflect several projects, which I will detail below:

1. A Phylogeny of the Oviraptorosauria
To understand the evolution of the skull of oviraptorids, one must understand how they got that way. This was that project, and it surprised me to learn that many things that were thought to be unique to oviraptorids had been around at the base of oviraptorids; it also helped separate Therizinosauroidea from Oviraptorosauria, or even next to it in maniraptoran phylogeny, and resolved some issues of which taxa were involved inside (like Avimimus portentosus). Believe it or not, I had this project close to 50% complete, before I lost my data. I would have certainly preferred personal examination of all material rather than pictorial and documentary analysis, and I would have wanted an essential pictorial atlas of the characters (included as supplemental data in order to cut the main text and images down), and that would have extended the project somewhat.

2. Cranial Anatomy of the Oviraptoridae
I would have, of course, preserved a total group analysis, but this small group is extensive — and time-consuming — enough. Rather than an evolutionary perspective, describing the cranial anatomy required the most hands on experience I lacked, and I would have preferred to do this with CT-scanning and physical models to describe the palate and rostrum of oviraptorids in detail, something that has not been done. Illustrating the skull in many peculiar fashions would have been illuminating to many workers, some of whom only read of the features. This would have been a “bare bones” analysis (forgive the pun). It would also have favored an essential pictorial atlas, but I think this time within the text. Some portions of this project would have included the relationship of the nasopharyngeal passage (alluded to in [1]), the shape and structure of the rhamphotheca on the upper and lower jaws, and the structure of the ventral maxillary “teeth” that seem to be the best thing most people have to say about oviraptorid skulls. A topic on the last bit, historical reference to the “teeth” and how they are often illustrated as actual white, pearly teeth, would have been a small side paper or something.

3. Functional Anatomy of the Jaw in Oviraptoridae
Drawing from Project 2, jaw anatomy would be the ultimate derivative and the ultimate course for my work, as it represents what I like most about anatomical science: functional anatomy, biomechanics, and the evolution of diet and development (and loss) of dentition. A muscular reconstruction would allow me to determine the functional relationship and method of biting and jaw movement in oviraptorids. Despite the diversity in oviraptorid jaw anatomy, and there is some substantive forms of it, the bite-action and degrees of movement of the mandible permit some interesting conclusions.

4. Diet in Oviraptoridae — Reaffirming Osborn’s Theory (with a Twist)
The title of my second abstract says it, but I never really got around to providing the data. This would have been something of an ecological paper, as I would have to show that seasonal egg-eating could both be viable energetically (for a homeotherm, even), and somehow show that the mandibular structure could handle this. While Osborn [3] originally proposed Oviraptor philoceratops was an ovophage on the partial basis of being located above a nest he believed belonged to a different dinosaur, and Barsbold [4] would support a durophagous diet in oviraptorids, due to the hyperperformance of the jaw structure mechanically; so over-built, was it, that he argued that they would have had to have fed on molluscs, both more plentiful and viable and harder-shelled seasonally than eggs, leading him to name an oviraptorid Conchoraptor gracilis [5], from the Greek κονγχέ (a seashell). But I digress. It was my theory [2] that oviraptorids were in fact egg-eaters, but could be so seasonally like other egg-eaters, but also opportunistic carnivores. But this walks into territory for data I wish I could publish without describing, so I will step out of this here.

Certainly interesting, this led to a side-project in which assessing seemingly predatory behavior in unconventional animals, such as Protoceratops andrewsi, but that was interrupted in part due to publication of works arguing, in no little terms, that the association would put Protoceratops as an egg-consumer. This was, however, not part of my conclusion, as it doesn’t detract from egg-eating in oviraptorids. The point would be to show that oviraptorids are adapted to a specialized form of jaw function that can only be best explained by durophagy. Assessing durophagy in other animals was also a side project, to which I collected data on globidontine mosasaurs, various notosuchian and eusuchian crocodilians, mixosaurid ichthyosaurs, placodonts, and anomodont synapsids. The project also led, less erringly but oddly, to other carnivorous-ish ornithischians.

5. Diet and Jaw Function in Oviaptorosauria, an Overview
Instead of condensing oviraptorids, I would have focused on them, then elaborated broadly to other oviraptorosaurs. This is largely because the jaw anatomy of other oviraptorosaurs is either less specialized or weird, or are less well-known. In Caenagnathidae, for example, all we have is a series of mandibles. What can we say about those? Well, quite a lot, but most of it requires zoological comparison, and this was going to be a piece on discussing relationship on living animals to fossil, especially when the fossil are so different from the living. Much ado has been made on the topic of how far we can apply living forms to fossil forms, and what data can be extrapolated: biogeography is used to help assign species, calculate continental breakup, timing of the evolutionary clock; body postures relate to gait, max speed, and even head attitude and neck posture; skin structures based on osteological correlates; and jaw anatomy relating to diet. But what happens when what you have differs from all other living animals? This is the problem of caenagnathids, for the most part. I would also have deviated off into what we know of caudipterids, that small basal group with tiny, needle teeth stuck in the front of its snout, as well as Incisivosaurus gauthier, resembling nothing so much as a birdy pleurosaur.

Aside from all of this, other projects (including assessing the viability of tooth-based taxa, troodontids in specific, and the ability to use a single bone as a phylogenetic tool [if it was possible]) were peaking, and as the years passed, nothing happened. This is where we are today, and why you’re reading this blog today, because I finally decided I needed to discuss these things instead of keeping them in my head. The reason I mention these abstract at all is that they have been mentioned by others, and they do exist, and they will be encountered. I am fortunate that they have not been mentioned further.

[1] Headden, J. A. 2001. Jaw function in Oviraptoridae (Dinosauria: Theropoda). Society of Vertebrate Paleontology, Abstracts. Journal of Vertebrate Paleontology 22(supp. to 3):59A.
[2] Headden, J. 2002. Henry Fairfield Osborn and revising the Oviraptor myth. Society of Vertebrate Paleontology, Abstracts. Journal of Vertebrate Paleontology 22(supp. to 3):59A.
[3] Osborn, H. F. 1924. Three new Theropoda, Protoceratops zone, central Mongolia. American Museum Novitates 144:1-12.
[4] Barsbold R. 1977. [Kinetism and peculiarity of the jaw apparatus of oviraptors (Theropoda, Saurischia)]. Trudy — Sovmestnaya Sovyetsko-Mongol’skoy Palyeontologicheskiya Ekspeditsiya 4:37-47.
[5] Barsbold R. 1986. Raubdinosaurier Oviraptoren [Oviraptoran thief dinosaurs]. p. 210-223 in Vorobyeva (ed.) Herpetologische Untersuchungen in der Mongolischen Volksrepublik. Instut Evolyucionnoy Morfologii i Ekologil Zhivotnykh im. A. M. Severtsova, Moskva. (Akademiya Nauk, Moscow)

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2 Responses to Oviraptorosaur Project Summary

  1. nick gardner says:

    hey jaime

    which email address is current for you? I have two on file.. a hotmail one and a yahoo one.

    nick

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