Phylum : Chordata
Class : Mammalia
Infraclass : Eutheria
Superorder : Euarchontoglires
Genus : Gomphos
Species : G. elkema
A team of paleontologists from the American Museum of Natural History and their colleagues have described the oldest, most complete fossil skeleton yet found of a primitive rabbit. The 55-million-year-old fossil animal, named Gomphos elkema is the oldest complete skeleton by about 20 million years and shows that some early lagomorphs, the group of animals that includes rabbits and hares, had a surprisingly modern, rabbit-like way of moving around. Its hindlimb was much longer than its forelimb, giving it a true "rabbit's foot" more than twice as long as its forepaw, which could be used for hopping. Other features of the skeleton, however, do not resemble modern rabbits. For instance, G. elkema, had a moderately sized tail, molar teeth with roots and distinct cusps, and a primitive jaw. Overall, this mix of features from modern rodents and lagomorphs supports the previously controversial but now generally agreed-upon idea that these two groups are closely related.
The G. elkema specimen was collected during one of the Museum's annual joint paleontological expeditions to the great fossil beds of Mongolia's Gobi Desert with the Mongolian Academy of Sciences. Co-led by Michael J. Novacek, Provost, Senior Vice President, and Curator in the Division of Paleontology, and Mark A. Norell, Chairman of the Division of Paleontology, Museum scientists will return this summer for the 16th consecutive year to explore this vast desert with their colleagues. The authors of the new research paper on G. elkema published in the journal Science include Dr. Novacek; Jin Meng, Associate Curator in the Museum's Division of Paleontology; Malcolm McKenna, Curator Emeritus in the Museum's Division of Paleontology; Robert J. Asher, Curator of Mammals at the Berlin Museum of Natural History; Guillermo W. Rougier, Associate Professor in the Department of Anatomical Sciences and Neurobiology at the University of Louisville; Demberlyn Dashzeveg of the Mongolian Academy of Sciences; and John Wible of the Carnegie Museum of Natural History.
"This research on G. elkema, along with the Museum's recently published research on fossils of a dinosaur-eating mammal, a tyrannosaur covered with protofeathers, and a sleeping troodontid, is representative of the unprecedented quality and quantity of paleontological discoveries and research projects currently undertaken by Museum scientists and their colleagues," said Dr. Novacek. "They also underscore the extraordinary quality and importance of fossils that have been recovered in recent years from Mongolia and northern China."
Dr. Asher, senior author of the new research paper, and Drs. Novacek and Meng were among the first to examine the fossil closely once its surrounding sediment was removed. "This animal's foot is huge," said Dr. Asher. "It's almost the size of its entire arm, like a modern rabbit's foot."
