Exceptionally Preserved Fossil Find Suggests All Dinosaurs May Have Been Feathered

Posted on July 2, 2012

Sciurumimus Fossil

A new species of feathered dinosaur has been discovered in southern Germany. The amazing fossil find, pictured above, provides the first evidence of feathered theropod dinosaurs that are not closely related to birds. Sciurumimus albersdoerferi lived about 150 million years ago. The fossil, which is of a baby Sciurumimus, was found in the limestones of northern Bavaria with preserved remains of a filamentous plumage, indicating that the dinosaur's entire body was covered in feathers. The genus name of Sciurumimus albersdoerferi refers to the scientific name of the tree squirrels, Sciurus, and means "squirrel-mimic," referring to the dinosaur's especially bushy tail.

Helmut Tischlinger, from the Jura Museum Eichstatt, says, "Under ultraviolet light, remains of the skin and feathers show up as luminous patches around the skeleton."

Mark Norell, chair of the Division of Palaeontology at the American Museum of Natural History, says, "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. 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. At this point it will surprise no one if feather like structures were present in the ancestors of all dinosaurs."

Palaentologist Oliver Rauhut, of the Bayerische Staatssammlung fur Palaontologie und Geologie, says, "All of the feathered predatory dinosaurs known so far represent close relatives of birds. Sciurumimus is much more basal within the dinosaur family tree and thus indicates that all predatory dinosaurs had feathers."

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 like T. rex and 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. The scientists say this means that species that stem from Sciurumimus are likely to have similar characteristics, such as feathers.

The Sciurumimus skeleton also represents the most complete predatory dinosaur ever found in Europe. It offers a rare glimpse at a young dinosaur. Apart from other known juvenile features, such as large eyes, the new find also confirmed other hypotheses.

Rauhut says, "It has been suggested for some time that the lifestyle of predatory dinosaurs changed considerably during their growth. Sciurumimus shows a remarkable difference to adult megalosaurs in the dentition, which clearly indicates that it had a different diet."

Adult megalosaurs reached about 20 feet in length and often weighed more than a ton. They were active predators, which probably also hunted other large dinosaurs. The juvenile specimen of Sciurumimus, which was only about 28 inches in length, probably hunted insects and other small prey, as evidenced by the slender, pointed teeth in the tip of its jaws.

The fossil find is described in a paper published here in the Proceedings of the National Academy of Sciences.

Photo: H. Tischlinger\Jura Museum Eichstatt

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