Azygonyx was a small tillodont mammal, likely the size of a cat to raccoon, that lived in North America during the Paleocene and Eocene in the early part of the Cenozoic Era.
The only fossils that have been recovered are from the Willwood and Fort Union Formations in the Bighorn Basin of Wyoming, United States, and date to the Clarkforkian to Wasatchian, about 56 to 50 million years ago.
[1] Azygonyx is placed in the suborder Tillodontia, an extinct group of mammals characterized by rodent-like incisors, clawed feet, and an elongated rostrum and mandibular symphysis.
[1] No complete skeleton of Azygonyx has been recovered, making the exact appearance and body size of the animal relatively difficult to determine.
[1] The large and laterally compressed claws and shallow trochlea of the astragalus suggests that the mode of life of Azygonyx was scansorial, or adapted for climbing.