Rare Ichnofossil - Lizard and Extinct Brontotheriid Track Association

This rare ichnofossil plate was collected decades ago from a site that has been only recently rediscovered. Most probably, the area was a near-shore shelf along Uinta Lake that existed during the Eocene.

This plate contains the extremely rare a member of the Brontotheriidae family, extinct mammals belonging to the order Perissodactyla that includes horses, rhinos, and tapirs. While brontotheres probably are most closely related to horses, they looked more like rhinoceroses. Brontotheres were browsers in warm temperate to subtropical environments and ranged from forest to open woodland. The group likely originated in North America during the early-middle Eocene and became extinct in North America by the end of the Eocene. They may have survived in Asia into the middle Oligocene.

The track on the far right is a partial impression of the four-toed front foot. The track on the far left is a partial of the three-toed rear foot.

In the ichnofossils association are also lizard tracks that are very distinct, including very discernable claws. I’ve only obtained a few tracks from the old collection with lizard tracks, and this is the only one with brontothere tracks.