Fossil Vertebrate Trackways

Terrestrial Fossil
Scientific Name: Ichniotherium

These fossil tracks were a recent and exciting find for Grand Canyon National Park. These early Permian tracks are 280 million years old and were made when the Grand Canyon area was covered by a sandy desert. These tracks were most likely made by diadectomorphs, a group of advanced amphibians that are thought to be closely related to the first reptiles. The absence of claw marks on these tracks is one of the main features that suggest they were made by an amphibian and not a reptile. It is surprising to find an amphibian living in such an arid environment, since they need to lay their eggs in water. This suggests that diadectomorphs were well adapted to living in deserts and perhaps had more reptilian characteristics than previously thought.

3D Ichniotherium tracks
Grand Canyon National Park, Arizona

A 3D model. This model shows a large slab of rock with fossils tracks on the surface. The model can be rotated and tilted using a computer interface.

These tracks, located in a large fallen block of the Coconino Sandstone within Grand Canyon National Park are evidence of early tetrapods inhabiting deserts during the late Paleozoic (early Permian).

Read more about the track block here: A copy of the publication is available here.

This fossil is managed in situ (in place) at Grand Canyon National Park, Arizona. Learn about paleontology in the National Park Service:

Learn more about Grand Canyon National Park’s Centennial:

Grand Canyon—Ichniotherium trackway

fossil tracks in sandstone fossil tracks in sandstone

Left image
Fossil trackway model with true color overlay.
Credit: NPS image by Jack Wood.

Right image
Fossil trackway model with color ramp overlay.
Credit: NPS image by Jack Wood.

Ichniotherium tracks found within the Grand Canyon are important clues to how early tetrapods colonized land. These tracks are especially important because the Coconino Sandstone was deposited as an erg and characteristic of a desert environment during the Permian (~280 million years ago). To help scientists, photogrammetry data can be used to create a map of the tracks, also known as a "heat map", which uses color to represent the changing  height of the surface features. Here, lowest areas are in blue and the highest are in red. Using the true color and the heat map together, the walking behavior of the animal can be better understood.

Part of a series of articles titled Grand Canyon Collections—Paleontology.

Grand Canyon National Park

Last updated: May 3, 2021