Most dinosaurs were like giant squirrels, new fossil evidence suggests
Could dinosaurs have been overgrown squirrels instead of overgrown lizards?
The possibility arose after scientists found the fossil of a squirrel-tail dinosaur that suggests dinosaurs were "feathered," National Geographic News reported.
National Geographic said the "exquisitely preserved" 150-million-year-old fossil was unearthed from a Bavarian limestone quarry, and was dubbed Sciurumimus albersdoerferi —a nod to Scirius, the scientific name for tree squirrels.
It added the new study suggested the newfound squirrel-tailed specimen is the most primitive meat-eating dinosaur with feathers and challenges the image of dinosaurs as "overgrown lizards."
"I was overwhelmed when I first saw it. Even apart from the preservation of feathers, this is certainly one of the most beautiful dinosaur fossils ever found," said study leader Oliver Rauhut, a paleontologist at the Bavarian State Collections of Palaeontology and Geology in Germany.
Before the find, paleontologists have found feathers only on coelurosaurs, birdlike dinosaurs that evolved later than megalosaurs like Sciurumimus.
Rauhut said that since Sciurumimus is not closely related to coelurosaurs, the new fossil suggests feathered dinosaurs were the norm rather than the exception.
"Probably all dinosaurs were feathered," he added, "and we should say good bye to the familiar image of the overgrown lizards."
The study was published this week in the journal Proceedings of the National Academy of Sciences.
The National Geographic report said Sciurumimus was likely a young megalosaur, a large, two-legged meat-eating dinosaur.
It had a large skull, short rear limbs, and long, hairlike plumage on its midsection, back, and tail.
Feathers were widespread
Corwin Sullivan, a paleontologist at the Chinese Academy of Sciences in Beijing, said past research had suggested feathers were widespread in the Cretaceous and late Jurassic periods (prehistoric time line), even if few specimens have been found.
Sullivan, who is not involved in the research, said feathered-dinosaur remains are sparse because "we only find them in places where conditions were just right for their bodies to be buried and preserved in a way that kept the feathers as well as the bones intact."
On the other hand, Sullivan said what is now more interesting is what Sciurumimus means for how dinosaurs evolved feathers.
He said that while scientists are not sure if dinosaurs other than coelurosaurs had feathers, Sciurumimus is "the first clear evidence" that feathers predated those birdlike dinosaurs.
Aside from meat-eating dinosaurs, hair-like feathers are also known in two bird-hipped dinosaurs, the report said.
The study authors said this suggests dinosaurs' common ancestor had feathers, though Sullivan said this is "an obvious possibility, rather than an obvious conclusion."
"We paleontologists are going to need to find more fossils—of things even less closely related to birds than Sciurumimus—to be sure," he said. — TJD, GMA News