It’s pretty standard for scientists to look at human skeletons to reconstruct past human health. But a new approach looks not at our ancestors themselves but the hardened gunk on their teeth to re-create the timeline of human dietary changes.
Scientists performed that analysis by looking at an array of ancient teeth. They found that shifts in the human diet over the millennia have led to big drop-offs in the diversity of good bacteria in our mouths—and the result is a severely weakened oral ecosystem and an increased risk of various diseases.
Saliva contains bacteria and minerals which accumulate on our teeth as plaque. Since skeletons can’t brush their teeth, this film eventually crystallizes on tooth enamel to become almost bone-like, preserving the bacterial DNA inside it. The DNA of bacteria in crystallized plaque provides a snapshot of a person’s diet, health and oral pathogens.
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
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
A cranium found in 1972 and the lower jaw of a newly discovered fossil,
shown reconstructed and combined above, are believed to be from
the same ancient hominid species.
The big-brained, upright primates of the genus Homo—the group to which we modern-day humans belong—evolved in East Africa around 2.4 million years ago. By half a million years later, Homo erectus, from whom we’re directly descended, was walking the plains near Lake Turkana in what is now Kenya. But anthropologists have increasingly come to believe that Homo erectus wasn’t the only hominid around. Three newly discovered fossils, detailed online this week in Nature, confirm that at least two other Homo species lived nearby—providing the strongest evidence yet that several evolutionary lineages split off in the genus’s early days.
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
One hundred and twenty million years ago, this fearsome creature roamed the skies above China. This recently discovered skull is the first evidence of this species of pterosaur (a flying reptile, not a dinosaur) that scientists have found, though similar fossils have been unearthed halfway around the world in Brazil. The new species name, Guidraco venator, is a portmanteau of Chinese and Latin words together meaning “ghost dragon hunter.” Those dramatic teeth have got scientists talking about how the heck it ate: did it hunt actively for the fish whose bones are in those clumps of poop (“copr” stands for “coprolite“) scattered around it, or did it scavenge? Either way, it looks like a creature that gets whatever it wants, when it wants it.
Above, the fossilized teeth running along the katydid’s left and right wings
that researchers used to reconstruct the creature’s call.
Well-preserved fossils can tell paleontologists myriad things, such as what color feathers dinosaurs had, how ancient spiders evolved, and what kind of microbes were around 3 billion years ago. The latest such revelation is rather whimsical, as well as being scientifically interesting. Scientists have been able to reconstruct the chirping of a Jurassic ancestor of modern katydids by examining the wings of an exquisitely preserved fossil specimen.
Katydids create their song by scraping one wing across the other, running a hard ridge of tiny teeth, like those on a comb, across the ridge on the opposite wing. The research team examined the size and shape of the teeth on the wings of Archaboilus musicus, as the Jurassic specimen is called, to come up with an estimate of the frequency of the sound that such scraping would have produced. They found that the resulting chirping would have fallen at 6.4 kilohertz, within the range of normal human hearing.
So, if you ever get the chance to travel back 165 million years, keep your ears pricked. You might hear something that sounds like this:
Image and video courtesy of Gu et al, PNAS