Jurassic Park is growing

New predatory species discovered in the Fränkische Plattenkalk

Skeleton of Juravenator strongi LMU Munich
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In the Plattenkalk of the Franconian Alb, scientists have discovered the fossil of a new dinosaur species. The relics of the chicken-sized predatory dinosaur are exceptionally well preserved - and suggest an illustrious relationship. These include, if somewhat removed, Tyrannosaurus rex and the first known bird Archeopteryx. A skin print on the tail of the Juravenator fossil shows that the animal - unlike several closely related species - was probably not feathered, which could shed new light on the evolution of feathers.

Although Juravenator starki will probably never make it into the top ten most popular dinosaurs in pre-school children, he is neither terribly scared nor heavyweight. For science, the find about which Dr. Ursula Göhlich of the Department of Geological and Environmental Sciences of the Ludwig Maximilians University (LMU) in Munich and her American colleague Luis M. Chiappe of the Natural History Museum of Los Angeles in the current issue of Nature report, nevertheless, a sensation. For the less than a meter tall Juravenator belongs to a group of carnivores, the Theropods, which was extremely rare in the Jurassic period of Europe.

"When we started working two years ago, Luis Chiappe and I quickly realized that the skeleton was something special, " says Göhlich. "After all, it is almost complete and very well preserved, but then it was a real surprise that we also see soft tissue."

Chicken-sized predatory dinosaur with claw fingers

Juravenator is one of the carnivorous predatory dinosaurs on two legs, the theropod or lizard pelvic, which originated more than 200 million years ago and was evolutively exceptionally successful. From them also the today's birds descend as next living relatives of the dinosaurs. Juravenator, for example, resembles the primitive bird Archeopteryx in its physique, but above all shows great similarities with the closely related Compsognathus.

The newly discovered species was only about the size of a chicken with a relatively large head, extremely long tail and strong hind legs. Each hand on the rather feeble forelegs wore three clawed fingers of varying lengths. Except for the missing last third of the tail, the skeleton is complete and exceptionally well preserved. Some features indicate that it was a juvenile. display

No trace of feathers

The soft tissue obtained clearly traces the outline of the tail. The tissue structure and the surface of the skin are also clearly visible. "But there is no trace of fletching, " says Göhlich. "The fossil transmission of feathers is only possible under very favorable conditions." As the soft tissue conservation shows, the Juravenator skeleton is exquisitely preserved, so if the animal had feathers, it would most likely have been transmitted. "

Compsognathus Early Image

A fletching at another body position can not be excluded, but remains unlikely. Although this is still unknown in fossils, there may have been seasonal differences - with extreme moulting. It is also conceivable that only adult animals were feathered. "In today's birds, there are nest stools that slap naked, " said G hlich. "This phenomenon, however, seems to be a very late invention of evolution, as other birds have feathers from the start as nest-nesters, and this is the only variant known in Cretaceous bird fossils. A feathering Juravenator would probably have had to be feathered as a juvenile. "

Assuming now that this species had no feathers, so is the "naked" Juravenator in the midst of feathered, close relatives. This, in turn, opens up the possibility that feathers have emerged more than once independently of each other, or have been lost in the course of evolution in certain species, such as Juravenator starki.

Name indicates location

"Juravenator starki", the name of the newly discovered dinosaur, can be traced to the animal itself and the location of the skeleton. Thus, "Jurassic" stands for the Jurassic and the Fränkische Alb, also called Fränkischer Jura. The rocks of this low mountain range were deposited in the Jurassic period, in which the dinosaur lived. "Venator" is Latin for "J ger" and indicates the r uberische life style of the animal, while "starki" immortalized the quarry of the family Stark, where the fossil was discovered.

The skeleton comes from Plattenkalken at pubic heads in Altm hltal, where more than a scientific sensation was recovered. The areas around Eichst tt and Solnhofen are among the most important sites worldwide. Fossils are not uncommonly common in the Plattenkalk, but are often very good and in some cases even with soft parts. The findings of the Solnhofen slaked lime, for example, are extremely spectacular and show just how diverse life was in the late Jurassic.

(University of Munich, 16.03.2006 - NPO)