Wednesday, October 06 1:54 pm
Reconstruction of cat-sized stem dinosaur Prorotodactylus isp. found in Stryczowice, Poland that was a quadruped with a dinosaur-like gait and orientation of the toes.
A researcher affiliated with the Museum has just described the oldest evidence of the dinosaur lineage: 250 million year-old fossilized tracks that are a few centimeters long.
“The oldest dinosaurs and their immediate relatives were small and rare,” says Stephen Brusatte, a graduate student affiliated with the Division of Paleontology at the American Museum of Natural History.
Just one or two million years after the massive Permian-Triassic extinction, a four-legged animal smaller than a house cat walked across fine mud in what is now central Poland. The prints of Prorotodactylus isp. show distinctive dinosaur-like features, including three prominent central toes parallel in alignment. The back edge of the print is straight, evidence of the simple hinged ankle that distinguishes dinosaurs from relatives like lizards and crocodiles.
The paper also describes 246-million-year-old Sphingopus isp. footprints, the oldest evidence of a bipedal and large-bodied dinosaur. This trackway–from a different but nearby site–may be the earliest evidence of moderately large-bodied and bipedal true dinosaurs. These tracks are larger at 15 centimeters long.
“The biggest crisis in the history of life also created one of the greatest opportunities in the history of life by emptying the landscape and making it possible for dinosaurs to evolve,” says Brusatte.
For more information, please see the official press release.
Near the Holy Cross Mountains of Poland where the oldest evidence of the dinosaur lineage is found are the three authors of the Proceedings of the Royal Society B paper (l to r): Grzegorz Niedźwiedzki, Stephen Brusatte, and Richard Butler. Credit: Marian Dziewiński
Thursday, September 16 2:31 pm
T. rex teeth on display in the Museum. Credit: D. Finnin
We’ve all heard this story — about 65 million years ago several large-headed, tiny-armed, bipedal predators, like Tyrannosaurus rex and Tarbosaurus, dominated Asia and North America.
But a decade of new fossil discoveries that have more than doubled the number of known tyrannosaur species has changed this tale. Older and smaller tyrannosaurs have made the evolutionary tree of this group richer and more complex. Furthermore, a series of innovative research projects on topics like bone growth and biomechanics have added an enormous amount of information about tyrannosaurs, so much so that the group could now be considered an exemplar for studying many themes in paleontology research. A new paper describing recent research and a new evolutionary tree appears in Science this week.
“We know more about tyrannosaurs than any other group of dinosaurs—even more than some groups of living organisms,” says Stephen Brusatte, a graduate student affiliated with the American Museum of Natural History.
“T. rex is the most iconic of all dinosaurs,” says Mark Norell, curator in the Division of Paleontology at the Museum. “The work on tyrannosaurs underscores how much can be done using modern techniques to understand the biology of fossil organisms. Many of us in the field now look at ourselves as biologists who just happen to work on dinosaurs.”
For more, please check the official press release.
Monday, August 30 1:30 pm
Balaur bondoc — the first reasonably complete skeleton of a carnivorous dinosaur from the last part of the Age of Dinosaurs in Europe, a description of which appears as the cover article in Proceedings of the National Academy of Sciences today — provides insight into an ecosystem very different from that of today. Europe at the end of the Cretaceous was an island archipelago dominated by smaller and more primitive animals than related species living on larger landmasses. Balaur bondoc, though similar in size to its relative, Velociraptor, has unusual features.
“We’ve all been waiting for something like this,” says Mark Norell, chair of the Division of Paleontology at the Museum. “Balaur bondoc is heavy, with unexpectedly stocky limbs and fused bones. It shows just how unusual the fauna of the area was during the waning years of the dinosaur era.”
Balaur bondoc, whose scientific name means “stocky dragon,” is a partial skeleton that was unearthed in Romania. It has 20 unique features when compared to its nearest relatives, including a re-evolved functional big toe with a large claw that can be hyperextended, presumably to slash prey. This feature, when combined with the large claw on the second toe that is typical of Balaur’s relatives, makes the new species double-clawed. Its feet and legs are short and stocky, with bones fused together, and the pelvis has enormous muscle attachment areas, indicating that this species was adapted for strength over speed. Finally, its hand is atrophied and some of the bones are fused, features that would have made grasping difficult.
“Balaur is a new breed of predatory dinosaur,” says Stephen Brusatte, a graduate student at Columbia University who is affiliated with the Museum. “Its anatomy shows that it probably hunted in a different way than its less stocky relatives. Compared to Velociraptor, Balaur was probably more of a kickboxer than a sprinter, and it might have been able to take down larger animals than itself, as many carnivores do today.”
The fossilized hindlimb Balaur bondoc showing the double sickle claws of the foot, one of 20 unique features found on a Late Cretaceous island in what is now Europe. Credit: Mick Ellison
