Bushy-Tailed Fossilized Theropod Could Mean that Most Dinosaurs Had Feathers

The skeleton of Sciurumimus albersdoerferi

A particularly well-preserved bushy-tailed fossilized theropod could imply that most of the dinosaurs actually had feathers. The dinosaur, named Sciurumimus albersdoerferi lived 150 million years ago, during the Jurassic period of the Mesozoic era, in what is now Germany.

S. albersdoerferi died in fine-grained sediments, allowing for an almost photographic impression of the filaments that covered its body. There have been other feathered therapods discovered before, inspiring the speculation that most dinosaurs had feathers instead of scales.

The previous fossils belonged to a group known as coelurosaurs, a relative latecomer. It was still an open question whether most theropods were feathers. The new fossil is described in the journal PNAS by lead author and paleontologist Oliver Rauhut, of Germany’s Ludwig Maximilian University.

S. albersdoerferi was significantly more basal in the evolutionary tree of theropods, implying that if it had feathers, so did the rest of the theropods. Thanks to S. albersdoerferi‘s taxonomic significance, and other quadrupedal, beaked dinosaurs, it’s possible that most dinosaurs had a filamentous body covering representing the plesiomorphic state for dinosaurs in general.

The feathers of S. albersdoerferi are strikingly beautiful, under different lights. Although S. albersdoerferi is named after a squirrel, it was large and carnivorous. The specimen was a juvenile, at just 28″ inches (71 centimeters) in length. As an adult, it would have been 20 feet (6 meters) from nose to tail. There are long filaments at the base of its tail, and unlike modern birds, whose feathers are optimized for flight, these feathers were most probably used for insulation.

Reference: “Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany” by Oliver W. M. Rauhut, Christian Foth, Helmut Tischlinger and Mark A. Norell, 2 July 2012, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.1203238109