Sciurumimus - looks like a squirrel, tastes like chicken...

Yesterday, me, my student Christian Foth, Helmut Tischlinger and Mark Norell finally got to publish the new theropod dinosaur from the Late Jurassic of southern Germany in the Proceedings of the National Academy of Sciences. The specimen had made the round in the press already last year, since it was exhibited at the Munich Show, a big mineral, jewel and fossil fair here in Munich. The fossil had been found in systematic excavations in a limestone quarry at Painten, north-eastern Bavaria, by a crew of fossil enthusiast and commercial collector Raimund Albersdoerfer, somewhen in the mid 2000s. Raimund rapidly recoginzed the scientific value of the find and looked for scientists to colaborate with in its description - I was the fortunate one that he found. Thus, it was through his courtesy that the specimen came to the Bavarian State Collection here in Munich for scientific analysis. Even more than that, Raimund himself requested that the specimen be included in the register of cultural objects of national importance, which insures that it will stay in Germany and that its current repository has to be made known to the authorities. This is a nice example of how science can profit from interaction with private collectors.

The new theropod photographed under UV light. (c) Helmut Tischlinger.

 

The specimen is certainly one of the most beautiful dinosaur fossils I have ever seen. It is a small theropod dinosaur (total length c. 70 cm) preserved lying on its right side in complete articulation. It comes from thin-banked to laminated limestones that lie below the famous Solnhofen limestones (from where the primary bird Archaeopteryx is derived), and is thus slightly older, dating back to the Late Kimmeridgian (some 151-152 million years old). Helmut Tischlinger, another private collector, world leading expert on UV-photography of fossils, and one of our co-authors on the paper actually saw the specimen shortly after its discovery in an unprepared state, so there can be no doubt as to its authenticity. But even apart from the exquisite state of preservation of the skeleton, there is more to the animal than what meets the naked eye - UV photography revealed the preservation of soft tissue in several parts of the skeleton. Especially striking were especially long dorsal filaments in the anterior part of the tail. These features led to the nickname that we used during the scientific investigation - "the squirrel". This later translated into the scientific name of the animal, Sciurumimus, meaning squirrel mimic (there are rumours on the web of this specimen being nicknamed "Otto". I have never heard of that name in reference to this specimen, and it was certainly no nickname we ever used). If you think this name is rather complicated - we first pondered whether to name it "Oachkatzlschwoaf", the Bavarian dialect name for a squirrels tail, which is even hard to pronounce for non-Bavarian Germans.

Skin remains and filaments preserved dorsal to the tail base. (c) Helmut Tischlinger.

Though a number of primitive characters were obvious from the beginning, when we first started working on this fossil, we were impressed by the overall similarity with Juravenator, which is of exactly the same age and comes from an adjacent basin, especially in the proportions. It took Christian and me three trips to Eichstätt to look at the original specimen of this taxon to make sure that it is not just another specimen or species of Juravenator. Thanks are due here to the director of the Jura Museum, Dr. Martina Kölbl-Ebert, who gave us access to Juravenator, even though we couldn't tell her why we needed to see it, since the existence of Sciurumimus was still a well hidden secret.

Our further resarch showed that Sciurumimus is not only clearly distinct from Juravenator, but that it is actually considerably more basal in the theropod family tree than other feathered dinosaurs known, being related to megalosaurids, large, predatory dinosaurs, such as the Middle Jurassic Megalosaurus. Thus, it it was not particularily closely related to birds, yet its entire body seems to have been covered in thin, hair-like filaments. It thus indicates that feathers might have been much more widely spread among dinosaurs than previously recognized. Surely, this is not an entirely new idea, but it is always nice to see your hypothesis confirmed by hard evidence...

Life reconstruction of the fluffy juvenile of Sciurumimus. I wonder if adults would have been as fluffy...

The function of these feathers was certainly not flight, but most probably thermoregulation. These structures resemble the down feathers of modern birds, which are great to keep your body warm (as anybody knows who has used a down jacket). This in term indicates that these dinosaurs probably had some kind of mechanism to actively regulat their own body temperature.

Much has been written in the media about the significance of this find, so I don't want to dwell too much on this here, and more information will become available with a detailed description that we are currently working on. In the meantime, Sciurumimus has found a comfortable home as a permanent loan to the Bürgermeister Müller Museum in Solnhofen, the very town whose name is world famous because of the well-preserved fossils in this area. There, the original fossil can be admired by everyone who visits the beautiful valley of the Altmühl, formerly the tropical archipelago of Solnhofen...