|Sue is something of a celebrity among dinosaurs, being the best-preserved T. rex fossil ever found. But in truth, the gender of dinosaurs is rarely, if ever, known. A study in 2005 first laid claim to a new way to sex dinosaurs using a distinctive bone formation. Now paleontologists in China have found that ancient birds also had this structure, confirming that birds and dinos shared similar gender divisions and reproductive habits.
Researchers excavated the 125-million-year old birds’ feathers, organs and bones from petrified lake-bottom mud in northeastern China. These birds, called Confuciusornis sanctus, were buried by the hundreds following catastrophic volcanic eruptions in the Mesozoic era.
Paleontologists in Tanzania have unearthed fossils from a new species of prehistoric reptile. The bones may have belonged to the world’s oldest dinosaur—or they may be from a reptile that kind of looks like a dinosaur.
Currently, the oldest confirmed dinosaur fossil dates back 230 million years. By this point in time, dinosaurs had grown in size and population to dominate the Earth. But when exactly did dinosaurs first enter the prehistoric picture, and how long did it take them to rise to such prominence? Paleontologists have narrowed the timeline down to the early or middle Triassic—the period of 20 million years before the oldest known dinosaur came to be. The newfound species, dubbed Nyasasaurus parringtoni, predates this fossil by another 10 to 15 million years, and falls right in the middle of paleontologists’ projected timeframe for the first appearance of dinosaurs.
Paleontologists now think they know how the predatory Tyrannosaur ate the well-protected Triceratops: by ripping its head off. The carnivore may have forcefully yanked on the bony frills around the neck of its horned prey in order to get to the rich meat beneath. The researchers, who reported their findings at the Society of Vertebrate Paleontology’s annual meeting last week, suggested this scenario after examining Triceratops skulls, where they found puncture and pull marks on the neck frills—along with bite marks on the head-neck joint that could only have been made on a severed head.
For a fuller explanation, replete with step-by-step illustrations, visit Nature News.
Drawing courtesy of Nate Carroll via Nature
This lucky wasp did not get eaten by the spider attacking it. But when we say “lucky,” we mean it only in a certain sense: moments after the wasp’s capture, they were both overtaken by a flow of tree resin and were preserved in amber for the next 100 million years, while their species and their dinosaur contemporaries from the Early Cretaceous period went extinct. The amber fossil is described in a new paper by George Poinar, the entomologist whose investigations into extracting dinosaur DNA from amber-locked mosquitoes inspired the book and movie, Jurassic Park. New research into the half-life of DNA puts that out of the question, but who knows: it might not be too late for these ancient bugs to cut a movie deal.
Photo via Oregon State University/Flickr
It’s always nice to put a face to a name—and not just in the case of humans. Paleontologist Paul Sereno just introduced the world to Pegomastax africanus, a small two-legged dinosaur that lived 200 million years ago, traipsing through what is now South Africa armed with a pointed beak, unexpectedly sharp canine teeth, and a bristling coat of quills. Calling to mind an image of such an unusual animal is difficult (I come up with a sort of parrot-wolf-porcupine-raptor mix which, while intriguing, is certainly not correct). Luckily, however, there are people like Tyler Keillor, a paleoartist who builds lifelike models of ancient animals, letting us see them face to face rather than as a list of features. In the video above, he reconstructs P. africanus layer by layer, starting with a resin skull and adding clay muscles, all the way up intricately painted silicone rubber skin and fishing-line quills.
[via Scientific American]
Sprechen ze deutsch?
This poem in praise of the Permian amphibian Eryops was scrawled on the back of a label now in the American Museum of Natural History by Jacob Boll, a Swiss-German fossil hunter involved in a tumultuous 19th-century paleontology feud.
Birds are the modern descendants of dinosaurs, but the exact details of the family tree are controversial. Archaeopteryx, the winged creature found in German fossil beds whose name means “first from a feather,” was long thought to be the first bird. Last summer, a Nature paper by Xu Xing, of China’s Institute of Vertebrate Paleontology and Paleoanthropology, claimed that Archaeopteryx was related to birds but actually belonged on a separate branch of the tree, with other bird-like dinosaurs.
Scientists still debate the rightful place of Archaeopteryx in the dinosaur-bird lineage, but what’s undisputed are Xu’s contributions to paleontology. He has named 60 dinosaur species, more than any other living paleontologist, and his stamping grounds are the fossil beds of Liaoning Province, northeast of Beijing, where many of the feathered dinosaurs and early birds were discovered. Kerri Smith enumerates Xu Xing’s contributions to the study of birds and their dinosaur relatives in a profile at Nature News: Read More
Paleontologists have long debated whether the dinosaurs were cold-blooded, soaking up heat from their surroundings like today’s reptiles, or warm-blooded, able to generate their own heat the way modern birds and mammals do. Some scientists pointed to dark bands called lines of arrested growth in dinosaur bones as evidence that the animals were cold-blooded. These lines, much like tree rings, show times when growth slowed down due to limited resources—perhaps, researchers suggested, during off seasons when the heat-absorbing animal wasn’t able to get enough energy from its environment.
A new study in Nature, however, examined the bones of 40 species of present-day ruminants—many-stomached, very much warm-blooded mammals—from around the globe, and found these animals’ bones show these same lines of arrested growth. Even mammals, it seems, slow down enough in tough times to leave these telltale marks in their bones. (Archaeologists have found similar bands, called Harris lines, in human bones from periods of malnutrition.) While this doesn’t prove dinos were warm-blooded, it knocks down an oft-cited piece of evidence that they weren’t. It’s possible that the dinosaurs evolved high body temperature, and passed the adaptation onto their descendants, today’s birds.
You’d think that a flying pterosaur with a 6-foot wingspan wouldn’t have to worry too much about getting eaten. Two recent fossils suggest otherwise.
Ed Yong at Not Exactly Rocket Science tells the perverse story behind this stunning fossil:
The Rhamphorhynchus [pterosaur] has a small fish lodged in its throat. It had just caught its prey and had started to swallow it. This animal was very much alive when Aspidorhynchus [a predatory fish] snagged it. But not for long – Rhamphorhynchus was probably pulled underwater and drowned. But the encounter was fatal for Aspidorhynchus too. Its skull wasn’t flexible enough to cope with large prey, and the pterosaur was too big and bulky for it to swallow.
It probably couldn’t get rid of its victim either. The pterosaur’s left wing bones are distorted, while the rest of its skeleton is intact. [The study’s authors] Frey and Tischlinger think that the fish tried to shake off its unwanted morsel, clearly to no avail. Perhaps the tough fibres in Rhamphorhynchus’s wing snagged in Aspidorhynchus’s tightly packed teeth. With neither party able to break free, both died.
The velociraptor in the fossil below didn’t fare too well either after eating a pterosaur, which was likely its last meal. The black arrows point to pterosaur bone fragments in its rib cage. The white arrow points to its own broken rib. Read More
What’s the News: Researchers have uncovered the youngest known dinosaur bone, dating from shortly before an asteroid slammed into Mexico’s Yucatan peninsula around 65 million years ago. The find, published today in Biology Letters, has revived debate among paleontologists over what, exactly, killed the dinosaurs.