- Extinct Brontotheriid Fossil Tracks
Class Mammalia, Order Perissodactyla, Brontotheriidae
Time: Middle Eocene
mm = 1 inch): Matrix 425mm X 450mm Four toed track 130mm X 150mm Three
toed track 110mm X 120mm
Site: Green River Formation, Sevier County, Utah
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.
plate contains the extremely rare tracks of a member of the Brontotheriidae
family, extinct mammals belonging to the oOrder Perissodactyla which
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.
small three toed tracks described as extremely rare horse tracks
have been found near Soldier Summit as reported in the The Journal
of Paleontology (Novermber 1968), the Brontotheriidae tracks are
not reported from Soldier Summit.
You can clearly see the three toes of the hind foot, and the four
toes of the front foot.
fossil pictures to enlarge