Kolponomos

Kolponomos is an extinct genus of carnivoran mammal that existed in the Late Arikareean North American Land Mammal Age, early Miocene epoch, about 20 million years ago. It was likely a marine mammal. The genus was erected in 1960 by Ruben A. Stirton, a paleontologist at the University of California Museum of Paleontology, Berkeley, for the species K. clallamensis, on the basis of a partial skull and jaw found on the Clallam Formation of the Olympic Peninsula. At the time, Stirton questionably assigned it to Procyonidae, its systematic position remained problematic until the discovery of more fossils including a nearly complete cranium from the original locality of K. clallamensis which helped identify it as part of the group from which pinnipeds evolved.

==Description== In life, species of Kolponomos had downturned snouts and broad, heavy molars that would have been suited to a diet of hard-shelled marine invertebrates, and their narrow snouts and anteriorly directed eyes indicate that they would have had stereoscopic vision. Large neck muscle attachments and robust foot bones combine with these features to suggest that Kolponomos filled a unique niche among marine carnivores, approached today only by the very distantly related sea otter. Due to the lack of a complete skeleton, however, it is difficult to make inferences about this genus' other adaptations. thumb|An artist's restoration of an otter-like K. newportensis compared to a human|left Based on the skull and jaws known, Kolponomos convergently evolved mandibular and bite features that had similarities to extant bears, sea otters, and even the sabretooth Smilodon. The anterior portion of the jaw becomes a functional anchoring fulcrum in both Kolponomos and Smilodon. Although dental morphology and heavy occlusal wear patterns are shared with the sea otter. Kolponomos' dentition was less efficient but exhibited higher stiffness than in the sea otter. Riley Black wrote that Kolponomos bit like a sabrecat, crunched like a bear.