Vertebrate Paleontology

/uploadedImages/CMNH_Site/Vertebrate_Paleontology/Graphics/eudibamus2.jpgEudibamus cursoris

Oldest known bipedal reptile 

Since 1993, Carnegie Museum of Natural History Curator Emeritus of Vertebrate Paleontology David Berman and Collection Manager Amy Henrici, along with colleagues Thomas Martens (Museum der Natur, Gotha, Germany) and Stuart Sumida (California State University), have been excavating the Bromacker Quarry, an abandoned sandstone quarry in Germany. In the photo below, Berman and Henrici are pictured with Sumida (at right) and research associate Rich Kissel, PhD (second from right).

The Bromacker excavations have yielded fascinating specimens that provide new information about the dominant life forms of the early part of the Permian period (290–250 million years ago), nearly 80 million years before the Age of Dinosaurs. Major discoveries at the Bromacker Quarry include the oldest known bipedal reptile, Eudibamus cursoris, and other reptile and amphibian species that, until now, were found only in the Permian deposits of the United States.

Paleontologists Dave Berman, Amy Henrici, Rich Kissel, Stuart SumidaThe scientific name for this new creature translates as "original runner on two limbs"—an apt description of Eudibamus cursoris, the oldest known example of a bipedal reptile. Click here for the press release on this discovery. 

The superbly preserved skeletal remains suggest that Eudibamus could sprint upright on its long, slender hind limbs, using its tail for balance. This evidence comes from close analysis of the leg and arm proportions of the specimen. Eudibamus' upper limbs are relatively short, while its lower limbs are comparatively long for its body size. These proportions are associated with bipedal locomotion, as longer legs increase both an animal's stride and overall speed.

Why did this reptile require such a swift foot? A diminutive herbivore like Eudibamus most likely used its speed to escape predators.

Compared to its contemporaries, Eudibamus belongs to a family of reptiles with an extraordinarily large geographic range. Berman and his colleagues suggest that the combination of lightning speed and herbivorous diet contributed to its widespread success.

Groundbreaking Bromacker Discoveries
Until their discovery in the Bromacker Quarry, the fossils listed below were found only in Permian deposits of the United States. The similarity between these European and American fossils provides undeniable biological evidence that North America and Europe were once connected as part of a single massive continent called Pangaea. Earth's continents sit on a patchwork of interlocking plates, which have been in constant motion over the past 750 million years. During the Permian period, all of the plates were joined as the supercontinent Pangaea.

Diadectes absitus was an herbivorous reptile approximately six feet in length. Previously known from fossils found throughout the United States, Diadectes was one of the first Bromacker animals that helped confirm the land connection between Europe and North America. Trackways of Diadectes footprints occur commonly at the Bromacker Quarry.
Diadectes absitus 


Seymouria sanjuanensis
was a carnivorous amphibian approximately two feet in length. Its presence at the Bromacker Quarry provides the best biological evidence for the supercontinent Pangaea. Berman has also collected this animal from rocks of similar age in New Mexico; however, the Bromacker specimens are the most complete and best-preserved examples of Seymouria.
Seymouria sanjuanensis 


Orobates pabsti
,
an herbivorous reptile approximately five feet in length, was also found. This superbly preserved reptile is very closely related to Diadectes and represents the most primitive plant-eating land animal ever found. A more slender body and limb bones distinguish this animal from Diadectes. Much remains to be discovered about this group, which is closely related to the group of reptiles that gave rise to mammals.
Orobates