Smithsonian.com

The Film Before Time: Palaeoblog commemorates the May 19, 1915 premiere of the movie The Dinosaur and the Missing Link: A Prehistoric Tragedy, which you can watch in two parts on YouTube, thanks to the Library of Congress. [Part 1 is embedded above] (One of the characters is named—I kid you not—Miss Araminta Rockface.) It features the earliest work of artist Willis O’Brien, who later brought King Kong to life.

Don’t Look, Goofy!!! Love in the Time of Chasmosaurs shows us excerpts from the 1983 Disney education book, Real Life Monsters. Mickey takes Goofy back in time—and, apparently, emotionally scars him for life after witnessing an Allosaurus chomp down on a Brontosaurus.

You Got a Question? Archosaur Musings checks out popular Q&A websites, and doesn’t like the answers: “[They] are profoundly inaccurate and misleading and give no indication at all of what they are based on, plus they completely contradict each other and one makes no attempt to correct the obvious problem that pterosaurs are not dinosaurs…. I assume that the people providing these answers assumed that they were right, but their profound ignorance of what they are saying is quite worrying.”

Move over, MacGyver: Paleochick demonstrates how you can take decent quality macro images of fossils using a cell phone and a hand lens.

A-to-Z: A young student asked Everything Dinosaur, “If you were to list all the names of dinosaurs in alphabetical order what would be the name at the bottom of your list?”

Not an easy question to answer: “With the relative explosion of dinosaur names from discoveries made by Chinese scientists there are a number of genera that we are aware of that begin with the letter ‘Z’.  However… we think that it would not be a Chinese dinosaur on the bottom.  That honor (we think), would go to Zupaysaurus, a genus of Theropod dinosaur.”

The “E” Word: Whirlpool of Life ponders the term “evolution”: “I have thought long and hard about whether or not to expand the word to refer to the history of the universe. After all, I reasoned, people might reject the Great Story out of hand, effectively tossing out the baby with the bathwater because of a bias against anything evolutionary….[However the existing term] underlines the fact that the evolution of life (and humans in particular) is not separate from the rest of nature…. By treating biological evolution as an entirely distinct process, we tend to construct a false dichotomy and ignore the many similarities between organic and inorganic transformations.”

When Fiberglass Dinosaurs Roamed the Earth: What’s creepier than an abandoned amusement park? An abandoned dinosaur amusement park. See a gallery of photos over at I09. (“It’s like Jurassic Park, but the T-Rex eats your soul.”)

The reconstructed skeleton of Typothorax coccinarum as drawn by Matt Celeskey. From the Journal of Vertebrate Paleontology paper.

Early dinosaurs and other Triassic creatures have been in the news quite a bit lately. From a new review of the origin of dinosaurs to the recognition of a mistaken dinosaur and the discovery of the skeleton of a fearsome predator closely related to crocodiles, some of the most interesting recent paleo news has focused on the time when dinosaurs and their ancestors were small animals in a world dominated by an array of strange reptiles. A new paper just published in the Journal of Vertebrate Paleontology adds to this wave of Triassic research, and it gives paleontologists a more complete look at one of the oddest vertebrates to have ever evolved.

Despite a superficial resemblance, the Triassic aetosaurs were not close relatives of the well-armored ankylosaurs. Instead aetosaurs were more closely related to crocodiles, and their extra armor plating has caused them to be informally called “armadillodiles” by many. As with most fossil vertebrates, though, fragments of aetosaurs have been found more often than complete skeletons, and reconstructing what they would have looked like in life has been made all the more difficult by the fact that their armor often became scattered after death. Nevertheless, several exquisitely preserved aetosaur skeletons have been found, and the new report provides the long-awaited details of two articulated aetosaur skeletons discovered in the 228- to 199-million-year-old rock of New Mexico.

Both specimens are of the aetosaur Typothorax coccinarum. The first skeleton, collected from the Badlands Ranch, is mostly complete except for some of the front parts of the body. The authors hypothesize that it was scavenged before it was completely buried, but despite this loss the specimen is remarkable because the skeletal parts are very close to their arrangement in life. The second skeleton is even more complete. Called the Revuelto Creek specimen, this skeleton preserves almost the entire body from the tip of the tail to the end of the snout—and both of these skeletons held a few surprises.

Aetosaurs were so well-armored that they had osteoderms around the orifice situated behind their hips called the cloacal vent, but in Typothorax the armor in this area of the body was unlike any described before. Rather than just have flat bits of armor, Typothorax had eight outward-curving spikes around its cloacal vent, leading the researchers to wonder what the function of these spikes might be. It is impossible to tell at the moment, but it certainly would have made mating an prickly prospect for these animals.

Of further interest were the limbs of Typothorax. The anatomy of the forelimbs was consistent with the hypothesis that some aetosaurs may have dug in the soil for food, and the hind feet of the specimens appeared to match Triassic-age trackways given the designation Brachychirotherium. It is always tricky matching a particular animal to a trackway (unless an animal literally dies in its tracks), but the correspondence between the Typothorax feet and Brachychirotherium tracks supports the idea that these tracks were made by an aetosaur.

All of this presents a finer picture of Typothorax than has previously been available. Not only will they allow scientists to better understand the arrangement of armor on these armadillodiles, but their skeletons may provide important clues to their paleobiology, as well.

For more on this new research, see the posts by Matt Celeskey (one of the paper’s co-authors), Bill Parker, and Jeff Martz.

Andrew B. Heckert; Spencer G. Lucas; Larry F. Rinehart; Matthew D. Celeskey; Justin A. Spielmann;Adrian P. Hunt (2010). Articulated skeletons of the aetosaur Typothorax coccinarum Cope (Archosauria: Stagonolepididae) from the Upper Triassic Bull Canyon Formation (Revueltian: early-mid Norian), eastern New Mexico, USA Journal of Verterbrate Paleontology, 30 (3), 619-642 : 10.1080/02724631003763524

Submitted by reader Jason Adams.

This ironic graffiti tag on the Carrboro, North Carolina was photographed by reader Jason Adams. The impact of an asteroid in what is now the Yucatan Peninsula was a bit of a bad day for them, but we are probably much better off without having to worry about tyrannosaurs wandering the suburbs or sauropods causing traffic jams. Still, some dinosaurs (birds) survived, so the next time you’re having a chicken dinner don’t forget about its more impressive extinct relatives.

Have you stumbled across a dinosaur in an unexpected place? If you have, and have a photo of the encounter, send it to us via dinosaursightings@gmail.com!

The commemorative Daspletosaurus coin issued by the Royal Canadian Mint.

Last week the Canadian Museum of Nature celebrated its 100th anniversary, and the Royal Canadian Mint has issued a new dinosaur coin to honor the venerable institution. The commemorative 50-cent coin features the tyrannosaur Daspletosaurus, which rushes the viewer when the coin is turned, and it is one of three dinosaur-themed coins to be released by the Royal Canadian Mint this year (the others will be emblazoned with similar images of the tyrannosaur Albertosaurus and the feathered dinosaur Sinosauropteryx). As with all commemorative coins, though, you will have to spend a pretty penny if you want one—each 50-cent coin costs $24.95 (Canadian), and so might be of interest only to the most die-hard dino fans.

Size of some of the largest sauropods compared. Red - Amphicoelias; Purple - Argentinosaurus; Orange - Supersaurus; Green - Diplodocus hallorum; Blue - Sauroposeidon. From Wikipedia.

Without a doubt, the sauropod dinosaurs were the largest animals to have ever walked the earth. Even the largest land mammal, the prehistoric rhino-relative Paraceratherium, would have been dwarfed by the biggest sauropods such as Diplodocus, Sauroposeidon, and others. How did these giants get to be so big?

Despite what late-night creature features about overgrown crocodiles and gigantic spiders might have you believe, the size to which organisms can grow is not unlimited. There are constraints on how big living things can get, from matters of engineering (such as how thick legs have to be to support a heavy body) and physiology (making sure blood gets efficiently pumped around the body) to the availability of enough food, and to understand how large sauropods attained such impressive sizes, paleontologists must attempt to untangle this confluence of factors. (Sauropods did come in a variety of sizes, including dwarfed species, but the exceptionally large genera have been the most vexing.) The latest attempt to do so has been put forward in a review by paleontologists Martin Sander, Andreas Christian, Marcus Clauss, Regina Fechner, Carole Gee, Eva-Maria Giebeler, Hanns-Christian Gunga, Jurgen Hummel, Heinrich Mallison, Steven Perry, Holger Preuschoft, Oliver Rauhut, Kristian Remes, Thomas Tutken, Oliver Wings and Ulrich Witzel in a paper recently published in Biological Reviews.

As has been highlighted by recently discovered dinosaurs like Panphagia, the lineage to which the sauropods belonged started off small. The sauropodomorphs, or the diverse group of long-necked herbivores from which the first sauropods evolved, were puny when compared to their later sauropod cousins, but as soon as the first true sauropods evolved near the end of the Triassic (200 million years ago) they reached estimated body masses of 10 tons or more. In fact, extremely large body size (in excess of an estimated 40 tons) evolved multiple times in different lineages, and even though we often focus on which dinosaur was the biggest of them all the truth of the matter is that from the Late Jurassic to the end of the Cretaceous, a time spanning 85 million years, the world was populated by numerous kinds of gigantic sauropods.

The authors of the paper considered everything from changes in levels of oxygen in the atmosphere and the availability of nutritious food to the lightweight construction of sauropod bones as explanations for the prodigious growth of the sauropods. The picture that emerges from all this is that a combination of features allowed sauropods to grow large. That the sauropod lineage evolved long necks early, for example, allowed them to exploit a range of food sources to fuel their bodies, and their light bones allowed them to overcome structure constraints felt by mammals due to the heavier bones of the latter group. More than that, becoming larger would provide them some relatively safety (at least as adults) from predatory dinosaurs.

The scientists determined that changes in sauropod body size do not track changes in atmospheric oxygen content, carbon dioxide content or changes in temperature, all of which had been hypothesized as driving sauropod body size. Instead it appears that some traits sauropods inherited from their ancestors, such as swallowing large amounts of food without chewing, allowed the beginnings of increased body size, which was further allowed by the development of evolutionary novelties along the way (i.e. a bird-like breathing system that would have allowed oxygen to be supplied to their bodies more efficiently). To put it another way, there was no single cause for the observed trend in body size, but rather an intertwined mass of pressures and constraints which shaped the evolution of these dinosaurs—a constant interplay between what was evolutionarily possible and what was advantageous to local conditions at a given time. While the review does not once and for all solve the mysteries of sauropod size, its recognition of contingency and constraint in their evolution will remain important to the ongoing debate about these dinosaurs.

Sander, P., Christian, A., Clauss, M., Fechner, R., Gee, C., Griebeler, E., Gunga, H., Hummel, J., Mallison, H., Perry, S., Preuschoft, H., Rauhut, O., Remes, K., Tütken, T., Wings, O., & Witzel, U. (2010). Biology of the sauropod dinosaurs: the evolution of gigantism Biological Reviews DOI: 10.1111/j.1469-185X.2010.00137.x