Eoarctos vorax, USNM 637259 (holotype), digital polygon surface reconstruction of assembled skeleton shown in orthographic perspective. A, right lateral view and B, anterolateral view. The majority of postcranial bones, plus the lower jaws, are scanned in a laser scanner with surface textures, supplemented by wrist bones (carpals) plus the skull that are produced by photogrammetry (see Methods section). These two digital capture processes resulted in surface mismatches in color and tonal qualities that are artificial and cannot be fully reconciled. Credit: Journal of Vertebrate Paleontology (2023). DOI: 10.1080/02724634.2022.2145900

A team of paleontologists at the Natural History Museum of Los Angeles County, working with a colleague from the Chinese Academy of Sciences and another with the North Dakota Geological Survey, has identified a new species and genus of an ancient bear-like arctoid. In their paper published in the Journal of Vertebrate Paleontology, the group describes where the fossil was found, its characteristics and condition.

The was originally dug up at a site on the Fitterer Ranch in the Brule Formation in 1982, in what is now a southwestern part of North Dakota. Recently, researchers finally gave the fossil and others found with it a close examination. The researchers describe the specimen as looking something like a raccoon, and roughly the same size—about a half-meter long. They note that it is in good condition—it included a baculum (a penile bone), which is rarely found in fossils because it does not preserve well. They also suggest it lived near a river and preyed on aquatic life.

A closer look at the fossil showed that it was a unique species and genus—they named it Eoarctos vorax, a combination of dawn and bear, a reference to its time on Earth and its likely hearty appetite. The research team found that the creature was related to modern bears, but was not an ancestor, and is now extinct. They also found that it lived approximately 30 million years ago.

Eoarctos vorax, F:AM 50392, mandible suffering heavy loss (left and right p1-3) or damage (left and right p4) to premolars and associated injuries to the lower jaws. A, right lateral, B, left lateral, and C, occlusal views. Credit: Journal of Vertebrate Paleontology (2023). DOI: 10.1080/02724634.2022.2145900

E. vorax had long, that would have allowed it to climb trees, the team found, though its legs and feet suggested it lived on the ground. It also had problems with its teeth. Most of those in the back of its mouth on the right side had been broken, which might have led to infection. And before the gums in the back had time to heal, more teeth were broken on the left side of the mouth. The researchers were not able to pinpoint a reason for all the broken teeth, but suggest it was due to biting something hard, such as a fruit pit. They conclude that the animal's odd eating habits may have contributed to its demise.

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More information: Xiaoming Wang et al, An exquisitely preserved skeleton of Eoarctos vorax (nov. gen. et sp.) from Fitterer Ranch, North Dakota (early Oligocene) and systematics and phylogeny of North American early arctoids (Carnivora, Caniformia), Journal of Vertebrate Paleontology (2023).

Journal information: Journal of Vertebrate Paleontology