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Last week, paleontologists Michael Taylor, Mathew Wedel and Richard Cifelli announced an instant dinosaur sensation: Brontomerus mcintoshi, the “thunder-thighed” dinosaur from the Early Cretaceous of Utah. All around the web, the sauropod was seen punting a large, feathery raptor in Francisco Gascó’s wonderful restoration. But the debut of Brontomerus was not a one-shot announcement left to fade after the initial run of news reports. Using their SV-POW! blog, study authors Taylor and Wedel have opened up public discussion about the dinosaur.

Taylor and Wedel’s first follow-up was a detailed response to questions raised by other scientists about the dinosaur. Paleontologist Jim Kirkland, who was directly involved in the excavation and preparation of the Brontomerus fossils in the 1990s, questioned numerous aspects of the new paper, and its authors responded in detail. Normally these kinds of discussions take place behind closed doors, but scientific arguments about Brontomerus have spilled over from e-mail to Facebook to blogs. For non-paleontologists, this is a rare look at the kind of scientific debate that often follows publication. A scientific paper is not a distilled piece of knowledge that can be put on a shelf somewhere. It is just an initial step in scientific debate.

The second supplementary post looked at the weird hip shape of Brontomerus. The original paper contained an illustration comparing the hip of the dinosaur with other sauropods, but the direct overlays of the hips in the blog post highlight the expanded portion of bone for muscle attachments that gave Brontomerus thunder thighs. As Matt Wedel himself writes in the post, “I like the kick in the brainpan that these overlays provide.”

Further posts about Brontomerus are planned for the SV-POW! blog, and I have to applaud what Taylor and Wedel have done. This is science communication done right. All too often new discoveries filter through press releases into news reports, but here two of the paper’s authors are directly engaging with their peers and the public. In addition, Mike Taylor put together a brilliant press package on his website, providing hi-res images, video, and a fact sheet of what the paper does and does not say. Should this kind of outreach come with every scientific paper? No, but if you’ve got a wonderful new dinosaur or other prehistoric critter that’s sure to get attention from the press, I think what Taylor and Wedel have done serves as a good model for how scientists can directly engage with reporters, peers, and dinosaur fans.

A pair of Abydosaurus - Early Cretaceous sauropods - snag a conifer for lunch. Restoration by Michael Skrepnick.

When we think about the Mesozoic world, dinosaurs often dominate our attention. They are the stars of countless museum displays and restorations, and everything else about their world just seems like window dressing. When visitors to Yale’s Peabody Museum look at Rudolph Zallinger’s beautiful (if outdated) “Age of Reptiles” mural, their attention is drawn to the tubby Allosaurus and the “Brontosaurus” wallowing in the swamp. The plants and animals Zallinger painted around the dinosaurs simply provide the setting for the more charismatic monsters.

But as with modern ecosystems, we can’t fully understand the lives of dinosaurs without knowing something about the supporting cast of organisms they lived alongside, especially plants. After all, plants were food to many, many dinosaur species, and plants undoubtedly influenced the evolution of dinosaurs just as dinosaurs influenced the evolution of plants. In fact, in a 1978 Nature paper, paleontologist Robert Bakker went so far as to suggest that dinosaurs had “invented” flowers.

Bakker’s reasoning went like this. During the Jurassic and Early Cretaceous many of the large herbivorous dinosaurs—especially the stegosaurs and sauropods—fed on plants like cycads and conifers. Given the size of these dinosaurs, they would have consumed massive amounts of plant food, and their preferences at the prehistoric salad bar opened up opportunities for fast-growing plants that were able to quickly grow in disturbed environments—namely, the angiosperms, which include flowering plants. Dinosaurs effectively cleared away the competition and allowed flowering plants to proliferate, and in turn, the changes in the plant communities influenced the evolution of dinosaurs with heavy batteries of chewing power, such as the hadrosaurs and horned dinosaurs.

It is a lovely idea—we can thank dinosaurs for flowers—but studies conducted during the past 30 years have scrapped the hypothesis. Better sampling of the dinosaur and flowering plant fossil records caused the correlation between the two to fall apart. There is no strong evidence that dinosaurs had anything to do with the origin or initial spread of flowers. Many dinosaurs ate angiosperms at the end of the Cretaceous, but that is about all we know for sure about their relationship.

Nevertheless, dinosaurs probably did have some effect on plant evolution. Think of herbivorous dinosaurs as plant predators. Unlike animals, plants can’t run away or otherwise evade their attackers, and so many plants have evolved defenses to discourage animals from eating them. Burning oils, toxic chemicals, thorns, microscopic spicules of silica and more—for plants, it’s war, and a paper published this week suggests that sauropod dinosaurs may have influenced the evolution of one plant defense.

Published by Andrew Leslie in the Proceedings of the Royal Society B, the study looked at changes in the anatomy of conifer cones over the past 300 million years. Among the trends Leslie noticed was that seed-containing cones began increasing the amount of protective tissue around their seeds during the middle of the Jurassic. In particular, a group of trees technically known as the Araucariaceae and popularly called monkey puzzles was among the first conifers to develop large, well-protected cones, and these trees have been cited as an important food source for the large sauropod dinosaurs that proliferated during this time. Perhaps, Leslie suggests, the feeding habits of the large, long-necked dinosaurs of the Jurassic provided the evolutionary pressure for the development of well-protected seed cones.

But dinosaurs were not the only plant predators around. Early birds and small mammals may have fed on the seeds of conifers and been even more important to the evolution of well-armored cones, Leslie noted, and the diversification of insects with powerful piercing, sucking and chewing mouth parts during the Jurassic probably played a role in seed cone changes, as well.  Many animals, both large and small, fed on various parts of conifer trees, but figuring out the exact details of these interactions is extremely difficult from our current vantage point.

References:

Bakker, R. (1978). Dinosaur feeding behaviour and the origin of flowering plants Nature, 274 (5672), 661-663 DOI: 10.1038/274661a0

BARRETT, P., & WILLIS, K. (2001). Did dinosaurs invent flowers? Dinosaur–angiosperm coevolution revisited Biological Reviews of the Cambridge Philosophical Society, 76 (3), 411-447 DOI: 10.1017/S1464793101005735

Hummel, J., Gee, C., Sudekum, K., Sander, P., Nogge, G., & Clauss, M. (2008). In vitro digestibility of fern and gymnosperm foliage: implications for sauropod feeding ecology and diet selection Proceedings of the Royal Society B: Biological Sciences, 275 (1638), 1015-1021 DOI: 10.1098/rspb.2007.1728

Leslie, A. (2011). Predation and protection in the macroevolutionary history of conifer cones Proceedings of the Royal Society B: Biological Sciences DOI: 10.1098/rspb.2010.2648

The known skeleton of Hadrosaurus. From Prieto-Márquez et al., 2006.

Described in 1858, the partial skeleton of Hadrosaurus foulkii was one of the most important dinosaur discoveries ever made. At that time, the few known dinosaurs were represented by a collection of scraps—paltry fragments that allowed paleontologists to reconstruct them first as giant lizards, and then as strange quadrupedal beasts. The elements of Hadrosaurus caused naturalists to revise what they thought dinosaurs looked like. Among the remains of Hadrosaurus pulled from a New Jersey marl pit were the arms and legs, and the difference in their lengths caused scientists to realize that this dinosaur could have walked on its hind limbs alone. Tracks discovered in England of a dinosaur walking bipedally, the 1866 discovery of the tyrannosaur Dryptosaurus in southern New Jersey, and Thomas Henry Huxley’s notion that dinosaurs were very bird-like all supported this conclusion, and spurred a rapid re-imagining of what dinosaurs looked like.

Strangely, though, Hadrosaurus has fallen from grace since the time of its description. It may have helped revolutionize the image of dinosaurs held by 19th century naturalists, but during the past century and a half no one has ever found a more complete skeleton. Nor is anyone likely to find one. The site where Hadrosaurus was discovered has been turned into a suburban development—a plaque on a rock commemorates the find—and the only major Cretaceous fossil site still being investigated in New Jersey is slightly geologically younger than the one where Hadrosaurus was found. This has presented paleontologists with a problem. Without more complete remains, how can we be sure that the bones of Hadrosaurus represent a distinct dinosaur and are not just pieces of some more completely known species found elsewhere?

A 2006 paper by Albert Prieto-Márquez, David Weishampel and Jack Horner cast doubt on the status of Hadrosaurus. In a reevaluation of the skeleton, they could not find any distinguishing characteristics. Even though the whole group of dinosaurs was named after it, there was no definite way to tell what sort of hadrosaur Hadrosaurus was.

But Prieto-Márquez has now changed his mind. In a paper just published in Zootaxa, he has concluded that the paltry remains of that first Hadrosaurus skeleton contain some diagnostic characteristics, after all. While the proportions of the upper arm bone, the humerus, are like those of the related iguanodont dinosaurs, Hadrosaurus has some minute specializations of the hip that differentiate it from almost all other hadrosaurs. A complete skeleton would be even more useful in this regard, but barring that, Prieto-Márquez has found a way to distinguish Hadrosaurus from similar dinosaurs. For now, New Jersey’s official state dinosaur is safe.

References:

Albert Prieto-Márquez (2011). Revised diagnoses of Hadrosaurus foulkii Leidy, 1858 (the type genus and species of Hadrosauridae Cope, 1869) and Claosaurus agilis Marsh, 1872 (Dinosauria: Ornithopoda) from the Late Cretaceous of North America Zootaxa, 2765, 61-68

Albert Prieto-Márquez, David B. Weishampel, and John R. Horner (2006). The dinosaur Hadrosaurus foulkii, from the Campanian of the East Coast of North America, with a reevaluation of the genus Acta Palaeontologica Polonica, 51 (1), 77-98

An adult Brontomerus punts a raptor in this life restoration by Francisco Gascó.

“Brontosaurus” was a great dinosaur name. The great “thunder reptile” of the Jurassic, there was no better moniker for the stoutly-built sauropod. Unfortunately, the name had to be tossed out in favor of Apatosaurus, but a different dinosaur just described by Michael Taylor, Mathew Wedel and Richard Cifelli has what I think is an equally awesome name. They have called it Brontomerus— “thunder thighs.”

Discovered during the mid-1990s in the Cedar Mountain Formation of eastern Utah, the fragmentary remains of Brontomerus represent an approximately 112-million-year-old cousin of the better-known Camarasaurus and Brachiosaurus. It is only the latest of several sauropod dinosaurs to be found in the Early Cretaceous rock of North America, confirming that the diversity of sauropods did not catastrophically drop at the end of the Jurassic as paleontologists previously thought. In fact, the authors of the new study note that there are other sauropod dinosaurs from the same formation waiting to be described—we are only just beginning to reconstruct what happened to North American sauropods after the Jurassic.

Frustratingly, our knowledge of Brontomerus is relatively limited. Private collectors had already worked over the quarry which held the dinosaur’s skeleton before scientists got to it. Not only did they remove bones, but they also destroyed some. As reported by the authors of the new paper, “Bones left exposed by these previous collectors were in various states of disrepair: some had been broken and their pieces used to hold down the remnants of a plastic tarpaulin.”

Despite these difficulties, though, the available material was enough to allow Taylor, Wedel and Cifelli to recognize the unique nature of Brontomerus. The most distinctive bone is the upper part of the hip—an ilium—from a juvenile animal, and this bone has an expansion called the preacetabular lobe that is much taller and larger than what is seen in other sauropods. In life, this wing of bone would have been the site of massive muscle attachments, giving the back legs of Brontomerus a beefy look that inspired its “thunder thighs” name.

A tentative reconstruction of an adult Brontomerus. The hip and other parts of assigned to the skeleton so far are in white; unknown parts are in blue. Image by Scott Hartman and modified by Mike Taylor.

Just why Brontomerus had so much extra space for muscle is a mystery. Taylor, Wedel and Cifelli offer three possibilities. Maybe Brontomerus had relatively longer legs than other sauropods, and so would require larger upper leg muscles. Then again, maybe the muscles would have made it easier for this dinosaur to rear up on its hind limbs, and perhaps this dinosaur could have walked on its hind legs for short periods of time. As depicted by Francisco Gascó in what is now one of my favorite dinosaur restorations ever, though, the big muscles of Brontomerus may have given it a formidable kick. Utahraptor lived about 12 million years before Brontomerus, but, if the two ever met, the sauropod had the muscle power to punt the feathery predator as it does in Gascó’s wonderful illustration.

The hip was not the only sauropod fossil to be found in the quarry. Additional skeletal elements include parts of several vertebrae, a rib, sternal plates and a shoulder blade from an adult. Whether all of these bones should be assigned to Brontomerus will require more complete skeletons to confirm, but for now, it is reasonable to hypothesize that the fossils found so far represent an adult and a juvenile. Even then, much of this dinosaur’s skeleton remains unknown, and paleontologists will have to keep digging to figure out what Brontomerus looked like and how it lived.

For more on Brontomerus, visit SV-POW! and see this post by study author Mike Taylor. Additional posts about the dinosaur will be added at SV-POW! in the near future.

References:

Taylor, M.; Wedel, M.; Cifelli, R. (2011). Brontomerus mcintoshi, a new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA Acta Palaeontologica Polonica DOI: 10.4202/app.2010.0073

A now-outdated reconstruction of Utahraptor, on display at the Museum of Ancient Life at Thanksgiving Point, Utah. Photo by author.

When it was released in 1993, Jurassic Park turned Velociraptor into a household name. Agile and cunning, it was a type of predatory dinosaur theater audiences hadn’t seen before. But paleontologists knew the movie’s raptors were drawn with a bit of artistic license. For one thing, the dinosaurs had actually been based on the sickle-clawed predator Deinonychus, and the movie monsters were much larger than either Deinonychus and Velociraptor. Then again, a discovery made just two years before the film’s debut confirmed that some raptors really did get as big as the ones in the film, and the timing of the discovery turned a scrappy collection of bones into a fossil celebrity.

Recovered during the summers of 1991 and 1992, the bones of the giant raptor were found just north of Utah’s Arches National Park during the excavation of an armored dinosaur that would later be named Gastonia. The site was an approximately 124-million-year-old part of the Cedar Mountain Formation, a slice of geological time in which ankylosaurs, iguanodonts, sauropods, raptors and other dinosaurs lived alongside each other, but it was not the only place where the predator was found. In the summer of 1975, paleontologist Jim Jensen collected hundreds of bones from the Dalton Wells Quarry near Moab, Utah, and among that collection were the previously unrecognized bones of the large predator.

Using both sets of fossils, James Kirkland, Robert Gaston and Donald Burge described the new dinosaur in 1993 and named it Utahraptor. Not very much of it was found—the raptor was described on the basis of a large second toe claw, hand claws, parts of the skull, a tibia and a few vertebrae—but what was recovered confirmed that it was a much larger cousin of Deinonychus. The authors of the paper estimated that Utahraptor may have been about 20 feet long and a little less than a thousand pounds, making it a somewhat stocky hunter. “If Utahraptor hunted in packs,” Kirkland and colleagues suggested, “it is conceivable that, in addition to preying on the iguanodonts in the fauna, sauropods up to 20 meters long may have been an important part of its diet.”

The timing was perfect: Utahraptor rode the wave of dinomania generated by Jurassic Park and became the star of several documentaries and video games. Frustratingly, though, our knowledge of this dinosaur is still very incomplete. An abstract presented at the 2001 Society of Vertebrate Paleontology meeting listed an additional 190 fragments representing nine individual animals of varying size, including some that may have been even longer than the original 20 foot estimate, but these specimens have yet to be fully described. Indeed, even more scraps of Utahraptor have been found since that time, but we have to patiently wait for further details about this famous predator.

References:

Britt, B.; Chure, D.; Stadtman, K.; Madsen, J.; Scheetz, R.; Burge, D. (2001). New osteological data and the affinities of Utahraptor from the Cedar Mountain Fm. (Early Cretaceous) of Utah Journal of Vertebrate Paleontology, 21, 1-117 DOI: 10.1080/02724634.2001.10010852

Kirkland, J.I.; Gaston, R.; Burge, D. (1993). A large dromaeosaur [Theropoda] from the Lower Cretaceous of Uta Hunteria, 1-16