Aclistomycter is an extinct genus of oreodont that lived in Texas during the Late Eocene epoch around 37.2-33.9 million years ago. This animal was a small herbivore that lived in forests and had short legs, suggesting that it was not a very fast or agile animal, so it would probably have some camouflage of stripes or spots to protect it. It had a very long tail and a skull with a rather flattened snout. Its body was small, robust and heavy, another trait that indicates that it was not a fast animal.