Pale Spinos–Sigilmassasaurus

In my past comments regarding the strange theropod dinosaur Spinosaurus aegyptiacus, a small storm began to brew as to how, and where the vertebrae fit in a series. An aborted project to revise this series on the basis of comparison to the cervical dorsal series in tetanuran theropods has now met with a hard–but very satisfying–thump.

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The Best Little Oviraptorid in Mongolia

The sweaty summers of the mid 1970s give way to cooler climes indoors, as a block of sandstone pulled from the red-and-orange rocks of the Djadokhta Formation in Mongolia’s southern Gobi Desert finds itself in Ulaanbator, the nation’s capital. Initially discovered during one of the joint Russian-Mongolian expeditions into the Gobi Desert, by a team including such notables as paleontologists Ivan Efremov, Rinchen Barsbold, the discovery was but one of the first of oviraptorosaurs in Mongolia, after a long gap since the recovery of the type specimen of Oviraptor philoceratops in 1923.

In the halls of the Geological Institute, the specimen would be extricated carefully, and then over the course of the next few years, painstakingly prepared. It would become the best preserved and freely-prepared oviraptorid skeleton (including skull) known. There are better oviraptorid skeletons now, and more complete. But none of them are mounted, or those that are mounted composed for multiple specimens, or are artificial. Originally labelled GIN (SPS) 100/42, the specimen was first attributed in late 1970s publication as Oviraptor philoceratops, but Barsbold would later express concerns over this assignment. Still, the label stuck and remained so until the mid-1990s, when new fossils recovered from the Djadokhta, at Ukhaa Tolgod, suggested that oviraptorid diversity had been staggeringly underestimated. And so that diversity increases with new finds from Mongolia and China. The specimen would be considered related to Citipati osmolskae, although not a member of that species, and thus earns the provisional name of “Citipati sp.” The specimen’s label has also received a facelift, when the Geological Institute of Mongolia changed its name, and thus its abbreviation, to the Mongolian Paleontological Center, or MPC. The specimen would become MPC-D (“d” for “dinosaur”) 100/42. Continue reading

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The Stocky Dragon

There is much we still do not know about the ancient origins of birds and near-bird animals, dromaeosaurs and troodontids. As we find more specimens of archaeopterygid or scansoriopterygid-like animals, of Anchiornises and what not, the tree becomes more of a bush, chaotic, involuted, interesting.

The Maastrichtian of Romania reveals a series of islands in what is now eastern Europe, the last remnants of the epicontinental sea that covers Europe diminishing as Africa looms closer to the south, rotating upwards and lifting the Alps of southern Europe. These islands formed intriguing biotas, comprised of small herbivorous ankylosaurs, hadrosaurs, pro-iguanodonts, and sauropods; and large birds and pterosaurs. The largest predators of these islands were probably azhdarchid pterosaurs. But amongst them, the small cat-sized Balaur bondoc is also known.

Balaur bondoc skeleton as bird Continue reading

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The Best Little Oviraptorid in Mongolia – Preview

As I wrote waaaay back in February of 2012 (damn!), my previous versions of the skeleton of the oviraptorid known as Citipati sp., or GIN 100/42 (or, simply “100/42”) were improperly scaled, improperly drawn, etc. Lots of errors, little means of fixing without redoing. I started the work on it, but this languished for years. In prep for a larger discussion of this specimen, I re-prepared the skeletal diagram, and present this here now as a lead-in:

Citipati nsp 100-42 skeleton med

Creative Commons LicenseThis work is licensed under a Creative Commons Attribution 4.0 International License.

As with other skeletal illustrations I’ve produced, this illustration is released under a Creative Commons license. Please be kind.

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Herbivores All the Way Down

Back in the 1980s and 1990s, a revolution in the way dinosaurs were conceived to have evolved occurred, in which a basal stock of croc-ish animals (this was during the “thecodont origin of … everything (?)” phase of archosaur relationship hypotheses) developed into the dinosaurs we know today, basically divided into three groups:

Theropod dinosaurs, including potentially birds; sauropods and their kin, the “prosauropods”; and ornithischians. While the latter group were considered herbivorous almost exclusively, with some omnivorous basal forms (like “fabrosaurs”), and the first group was almost exclusively considered carnivorous with some omnivorous forms, the herbivory/carnivory aspects never crossed over. In Sauropodomorpha, the group containing sauropods and “prosauropods,” basal forms were considered mostly herbivores, with some carnivorous trends (some of it based on confused fossils of giant croc-like rauisuchids or postosuchids). But this meant that theropods were nested within a group that trended, at its base, towards herbivory.

All dinosaurs, then, would have had a little plant-eater in their near-ancestry. Continue reading

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Strange Tid[w]ings

Yi qi conceptsThe new small theropod Yi qi was described 29 April, 2015, far too late to be a practical joke for All Fools’ Day (by 4 weeks, precisely). Why would it be? The animal, described by Xu Xing and a number of colleagues, is based on a single specimen of a mostly crappy slab. Continue reading

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Facial Expressions

Models for "cheeks" in Ornithischia.How many faces do I have?

The various and many ways to make a “cheek,” and the various facial tissues for which we have primary (preserved remains) and secondary (inferred) evidence for, in fossil sauropsidans. (These images are CC-BY-ND-NC. Please don’t take them without permission.)

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Posted in Art, Biological Comparison, Biology, Biomechanics, Paleobiology, Paleontology, Reconstruction | Tagged , , , , , , , | 7 Comments