From “Newly Discovered Dinosaur Implies Greater Prevalence of Feathers; Megalosaur Fossil Represents First Feathered Dinosaur Not Closely Related to Birds” (ScienceDaily, July 2, 2012), we learn:
A new species of feathered dinosaur discovered in southern Germany is further changing the perception of how predatory dinosaurs looked. The fossil of Sciurumimus albersdoerferi,which lived about 150 million years ago, provides the first evidence of feathered theropod dinosaurs that are not closely related to birds.
“This is a surprising find from the cradle of feathered dinosaur work, the very formation where the first feathered dinosaur Archaeopteryx was collected over 150 years ago,” said Mark Norell, chair of the Division of Palaeontology at the American Museum of Natural History and an author on the new paper along with researchers from Bayerische Staatssammlung für Paläontologie und Geologie and the Ludwig Maximilians University.
Theropods are bipedal, mostly carnivorous dinosaurs. In recent years, scientists have discovered that many extinct theropods had feathers. But this feathering has only been found in theropods that are classified as coelurosaurs, a diverse group including animals likeT. rexand birds. Sciurumimus — identified as a megalosaur, not a coelurosaur — is the first exception to this rule. The new species also sits deep within the evolutionary tree of theropods, much more so than coelurosaurs, meaning that the species that stem from Sciurumimus are likely to have similar characteristics.
“Everything we find these days shows just how deep in the family tree many characteristics of modern birds go, and just how bird-like these animals were,” Norell said. “At this point it will surprise no one if feather like structures were present in the ancestors of all dinosaurs.”
But if feather like structures were present in the ancestors of all dinosaurs, how much time does that allow for the gradual evolution of feathers?
This feathered fossil was a baby, of a carnivore that would be twenty feet long as an adult and weigh about a ton. One wonders whether it will turn out that many such dinos had feathers only as babies.
See also: “One of the strongest lines of evidence” for dinosaurs as cold-blooded just collapsed.