December 19, 2008

At the Dawn of Dinosaur Science

8:26 am

Sacral, Lumbar, and Caudal Vertebrae of the Megalosaurus, from Buckland, 1824

I am induced to lay before the Geological Society the annexed representations of parts of the skeleton of an enormous fossil animal, found at Stonesfield near Woodstock, about twelve miles to the N. W. of Oxford ; in the hope that, imperfect as are the present materials, their communication to the public may induce those who possess other parts of the same reptile, to transmit to the Society such further information as may lead to a more complete elucidation of its osteology.

The good Reverend William Buckland published these words in 1824, introducing an article entitled, “Notice on the Megalosaurus or great Fossil Lizard of Stonesfield.”* Eighteen years later, when Sir Richard Owen became the first person to utter the word “dinosaur,” Buckland’s Megalosaurus was a charter member of the group. Buckland’s 1824 notice is recognized as the first scientific description of a dinosaur.** A PDF of this article was recently made available for download (along with a sampling of other notable 19th century papers) from the Geological Society of London.

Sample papers from the Transactions of the Geological Society of London, 1811-1856.

* This notice illustrated a scant 7 pages of text with 5 beautiful lithographic plates of the fossils, reproduced at 25%, 50%, and full scale. I am inclined to believe that this very nearly approaches an ideal ratio of text to figures in a fossil description.

**Although historians are aware of at least one notable early attempt to describe probable Megalosaurus remains.

—Matt Celeskey.

File under: Cretaceous, Dinosaurs.

Comments on record: (0)

Austroraptor cabazai

12:02 am

—Matt Celeskey.

File under: Cretaceous, Dinosaurs.

Comments on record: (3)

December 10, 2008

Skorpiovenator bustingorryi

4:07 pm
  • Quick sketch of Skorpiovenator bustingorryi
  • New Theropod: Skorpiovenator bustingorryi
  • Name Means: Bustingorry’s Scorpion Hunter (Manuel Bustingorry owned the land where the fossil was found, and the describers report an “abundance of living scorpions moving around the excavation.”)
  • Relations: Abelisaurid theropod
  • Holotype: MMCH-PV 48, an almost complete skeleton
  • Location: Neuquén Province, Argentina
  • Age: Late Cretaceous (~93,000,000 years old)
  • Info: Skorpiovenator belongs to the Abelisauridae, a distinctive family of large carnivorous dinosaurs that prowled the Gondwanan supercontinent during the latter half of the Cretaceous period, from about 95 to 65 milion years ago. During this time, Gondwana was beginning to break up into several more familiar landmasses—South America, Africa, Madagascar, India, Australia, Antarctica—and palontologists have suggested that the relationships and distribution of abelisaurids might help determine the order in which Gondwana split apart.
  • In Canale et al.’s phylogeny, Skorpiovenator is most closely related to other South American abelisaurids, including Ekrixinatosaurus, Ilokelesia, Carnotaurus, and Aucasaurus. They share a suite of features that suggest that they were turning their skulls into shock-absorbers: hyperossified ornamentation atop their heads, struts of bone projecting into or sealing off parts of the orbit, and shortened muzzles. This last feature inspired a name for this abelisaur subgroup—the Brachyrostra, or “short snouts.”
  • If this interpretation is correct—that South America had its own endemic radiation of short-snouted abelisaurs for the last 30 million years of the Cretaceous, this might suggest that South America was isolated from other Gondwanan landmasses with non-brachyrostran abelisaurs (places like Africa and Madagascar). However, other abelisaur phylogenies present different conclusions, and, as Canale and his coauthors point out, there are certainly other groups of Cretaceous Gondwanan animals that have their own stories to tell.
  • Reference: Canale, J. I., Scanferla, C. A., Agnolin, F. L., and Novas, F. E., 2008. New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods. Naturwissenschaften published online 05 December 2008. doi: 10.1007/s00114-008-0487-4
  • Elsewhere on the Web:

—Matt Celeskey.

File under: Cretaceous, Dinosaurs.

Comments on record: (8)

December 7, 2008

Turtle Shells and Flying Pigs

9:33 pm

Diagram of IVPP V 13240, Paratype of Odontochelys semitestacea

Diagram of IVPP V 13240, Paratype of Odontochelys semitestacea. After Li et al. 2008.

Zach Miller, who runs the blog When Pigs Fly Returns, has a good-sized post up about the origin of turtle shells, especially in light of the recent discoveries of Chinlechelys and Odontochelys. I’ve been trying to wrap my head around the same issues, and I’ve started by coming up with some color-coded diagrams of these unique Triassic testudines to look at how the different bones of the shell are expressed and interpreted. I’ll post more about them here eventually, but Zach’s been able to put them to good use in his latest post, How the Turtle Got Its Shell. Check it out!

—Matt Celeskey.

File under: Reptiles, Triassic, Webbery.

Comments on record: (2)

November 26, 2008

Odontochelys semitestacea

2:05 pm

—Matt Celeskey.

File under: Reptiles, Triassic.

Comments on record: (3)

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