SPECIES: Unknown ICHNOGENUS: Chelichnus (=Laoporus) LOCATION: Ash Fork, Arizona, Coconino Sandstone AGE: Early Permian (Approx. 270 million years)
There are three very distinct footprints with fine toe marks. Overall there are nine individual tracks, most of them part of a quite visible trackway. The plate is quite solid, thick and heavy, weighing in at 4.8 lbs.
This track way was made by a quadrupedal tetrapod vertebrate and has been attributed to synapsids, specifically Laoporus. The legs of these animals were under the body, not out to the side. The mammals of today are but one branch of the Synapsida, a great vertebrate group with a 300 million year history. Pre-mammalian synapsids -- dominated the land vertebrate fauna of the Permian and early Triassic before losing ground to the diversifying dinosaurs and other archosaurs. These pre-mammalian groups of synapsids have at times been called "mammal-like reptiles". This term is however not accurate. None of the synapsids were actually reptiles. These tracks were probably made when the animal was walking across a sandy matrix covered by very shallow water. This footprint plate was legally collected on private land by with the owner’s permission.