Hairy Museum of Natural History

Dr. Robert Bakker has graciously forwarded along two more images from the Dracorex hogwartsia description:

Used by permission, © R. T. Bakker 2006

Above: A reconstruction of the presacral spinal column, hips, and skull of Dracorex hogwartsia. The skull and first, fourth, eighth, and ninth cervical (neck) vertebrae are the only known Dracorex bones. These were used to interpolate the missing neckbones. The hips, ribs, and dorsal (back) vertebrae are restored from Stegoceras validum with some proportions taken from Homalocephale calathocercos. Total length of the segment shown here: 1.6 meters.

Used by permission, © R. T. Bakker 2006

Above: The tip of the snout of Dracorex hogwartsia. The upper left drawing is in dorsal-anterior (top-front) view; the bottom drawing is in ventral (bottom) view; and the upper right is a view of the snout on the animal’s left side. Unlike other pachycephalosaurs, Dracorex does not have a cutting edge at the tip of its upper jaw. Instead, the bone seems to be modified into a textured crushing surface similar to (but smaller than) the plant-grinding surface at the tip of a modern manatee snout. Scale bar = 5cm.

—Matt Celeskey.

File under: Cretaceous, Dinosaurs, Recent Discoveries.

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The mounted skull and neck of Dracorex hogwartsia.
Photo from the Children’s Museum
of Indianapolis press release.

The lines between science and fiction blurred just a little bit today when paleontologists unveiled a dragon-like dinosaur named after the School of Witchcraft and Wizardry in J. K. Rowling’s “Harry Potter” novels.

Dracorex hogwartsia, “The Dragon King of Hogwarts,” is a new species of pachycephalosaur whose skull was covered in a fantastic array of spikes, tubercles, and hornlets. The skull was first shown to the public last year at the Children’s Museum of Indianapolis, but its formal name and description have just been published in the latest New Mexico Museum of Natural History and Science Bulletin (part of the Federal Fossil Conference currently underway in Albuquerque). A team of researchers led by Dr. Robert Bakker decided to name the creature “after the fictional ‘Hogwarts Academy,’ invention of author J. K. Rowling…in honor of her contribution to children’s education and the joy of exploration.”

The skull of Dracorex presents an interesting mix of advanced and “primitive” characters. Like its close relatives and contemporaries Pachycephalosaurus and Stygimoloch, Dracorex had a long snout and multiple rows of nodes and spikes across its nose and around the rear edge of its skull. Unlike them, however, Dracorex is missing one key pachycephalosaur feature–a thick dome of bone atop its skull.

Other flat-headed pachycephalosaurs are known from fossil sites in Asia, but these have a very different style of cranial ornamentation than Dracorex, Stygimoloch, and Pachycephalosaurus. The authors suggest that Dracorex is secondarily domeless–that is, its immediate ancestors were fully-domed, but Dracorex re-evolved the domeless condition of more distant ancestors.

Headbutting Dracorex.

Used by permission, © R. T. Bakker 2006
From the NMMNH&S Press Release.

Abstract–The pachycephalosaurid Dracorex hogwartsia, n. gen., n. sp., is a new pachycephalosaurin based on a nearly complete, and excellently preserved, young-adult skull from the Upper Cretaceous Hell Creek Formation (Lancian) of South Dakota. D. hogwartsia shows an unexpected mix of truly very primitive and very advanced features: no dome; wide open supratempral fenestrae; large, spiked nodes on the squamosals; nodes of various shapes and sizes covering the skull including the cheek and snout; and a very long snout and tooth row. The so-called “primitive” nature of the skull (i.e.: the well-developed supratemporal fenestrae and discernable peripheral skull elements: anterior + posterior supraorbitals and postorbitals 1 + 2, suggest that these features are present as the result of paedomorphosis. Consequently, all previous phylogenetic analyses are considered inadequate. At least three pachycephalosaurins co-existed in the Lancian - Dracorex, Pachycephalosaurus, and Stygimoloch. Strong sexual-social selection probably generated the morphological diversity in skull shapes of these Late Cretaceous pachycephalosaurids.

Bakker, R. T., Sullivan, R. M., Porter, V., Larson, P., & Salsbury, S. J. 2006 “Dracorex hogwartsia, n. gen., n. sp., a spiked, flat-headed pachycephalosaurid dinosaur from the Upper Cretaceous Hell Creek Formation of South Dakota.” New Mexico Museum of Natural History and Science Bulletin 35, p. 331–345.

*No tangential discussion of Harry Potter is complete without a reference to “Wizard People, Dear Readers”–Brad Neely’s unauthorized, delightful, and profanity-riddled re-envisioning of the film “Harry Potter and the Sorcerer’s Stone.” It is free for the download here.

Update: The NMMNH&S has a fairly extensive Press Release as well as this drawing of the reconstructed skull of Dracorex in side and top views, penned by Robert Bakker:

Used by permission, © R. T. Bakker 2006

—Matt Celeskey.

File under: Cretaceous, Dinosaurs, Recent Discoveries.

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The holotype skeleton of Yinlong downsi.
Photo Credit: IVPP

Meet Yinlong downsi, the earliest ceratopsian yet discovered. The name Yinlong means “Hidden Dragon,” due to the fact that the fossil was found in China where the movie “Crouching Tiger, Hidden Dragon” was filmed, while “downsi” honors the life and work of Will Downs.

Yinlong comes from early Late Jurassic rocks, 20 million years earlier than the next-oldest ceratopsian and a good 80 million years before well-known ceratopsians like Triceratops. As might be expected, Yinlong seems to come from the base of the ceratopsian family tree, and its relatively unspecialized nature is helping scientists figure out exactly what other dinosaurs ceratopsians are related to.

For about 20 years, paleontologists have suspected that the horned and frilled ceratopsians were closely related to the thick-headed pachycephalosaurs. This relationship was largely based on the fact that both groups had a shelf of bone that extended back over the base of the skull, a feature that has led scientists to combine the two into one overarching group–the Marginocephalia (”Shelf-heads”). But the skulls of both these groups are so highly modified that there has been some debate as to whether this was an actual feature that they inherited from a common ancestor, or just an accidental similarity that each group independently developed while evolution was messing with their heads.

The skull of Yinlong downsi (snout is to the left).
Photo Credit: James M. Clark

The anatomy of Yinlong points to the former scenario. The beak-like rostral bone at the tip of its snout is a defining feature of the Ceratopsia and places Yinlong squarely in that group. But the expansion of the back of its skull is more similar to pachycephalosaurs than ceratopsians, complete with roughened borders and small knobs of bone. Yinlong seems to show that both ceratopsians and pachycephalosaurs started out with a similar expansion of the back of their heads before evolving their own distinct extravagances–ceratopsians with long horns and shield-like frills, and pachycephalosaurs with nodes, knobs, spikes, and domes.

As if that weren’t enough, Yinlong offers clues to the origin of the Marginocephalia as well. Yinlong seems to bridge the gap between advanced marginocephalians and an earlier group of dinosaurs, the heterodontosaurs. This relationship has been suggested before, but Yinlong seems to offer the best evidence to date, with several characters of its skull and postcranial skeleton shared with the Heterodontosaur family.

Xu X., Forster, C. A., Clark, J. M., & Mo, J. 2006 “A basal ceratopsian with transitional features from the Late Jurassic of northwestern China.” Proceedings of the Royal Society B: Biological Sciences. First Cite Early Online Publishing.

George Washington University has a press release online in addition to the images shown here. A PDF of the paper is available to download as well. All this brought to my attention via the good folks on the Dinosaur Mailing List, a great way to keep up on the latest Mesozoic news.

—Matt Celeskey.

File under: Dinosaurs, Jurassic, Recent Discoveries.

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Little Vallesaurus cenensis, a 16cm long Triassic drepanosaur from Northern Italy, has finally been officially introduced to the scientific community. Its name and photograph have been appearing in technical and popular literature since 1991, but the formal description of the holotype was just published this month in Rivista Italiana di Paleontologia e Stratigrafia.

Drs. Silvio Renesto and Giorgio Binelli, of the Universitá degli Studi dell’Insubria, have described the only known specimen of Vallesaurus, a single tiny skeleton preserved in limestone deposited in a Late Triassic sea. Like most other drepanosaurs, Vallesaurus was arboreal, making its way through the Triassic treetops with an opposable big toe and prehensile tail. These adaptations have led one researcher to call the group Simiosaurs, or “Monkey-Lizards,” although Renesto and Binelli use the more traditional family name: Drepanosauridae, after Drepanosaurus, the first of its family described.

Above is a painting of Vallesaurus made last year for the “Monkey-Lizards of the Triassic” gallery here at the HMNH. With a better description now published, I can see that its forelimbs should be shorter while its fingers should be larger and longer, and its snout should be quite a bit sharper at the tip. Of interest for future restorations are the patches of skin preserved on the holotype, showing “granular” scales on its head and lizard-like, overlapping scales on its tail. This is the first example of fossilized drepanosaur skin I’ve heard of.

Renesto and Binelli reveal another surprise when they examine how Vallesaurus and the drepanosaurs fit into the reptile family tree. But that’s a topic I’ll save for a future post…until then, check out Silvio Renesto’s newly updated Vallesaurus pages for photographs and more details.

Renesto S. & Binelli G. 2006. “Vallesaurus cenensis Wild, 1991, a drepanosaurid from the Late Triassic of Northern Italy.” Rivista Italiana di Paleontologia e Stratigraphia. 112: 77-94.

—Matt Celeskey.

File under: Recent Discoveries, Reptiles, Triassic.

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Glancing at the calendar I see that it has been a full 32 days since anything has been updated here the Hairy Museum. Apologies to any faithful readers or folks popping in from one Google search or another. It has been a fairly full month here at HMNH HQ, and my attentions are bent towards certain grand plans that have been set in joyous motion.

Posting will waver between sporadic and nonexistent for the next month or so, but check back here at least once over the coming week. There are some nifty paleo-news stories on the horizon…

—Matt Celeskey.

File under: Miscellany.

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