Like a modern pangolin, Patriomanis americanus was a small mammal whose most distinctive feature was its scaly outer armor. The scales are soft at birth, but harden as the animal matures, resulting in a covering that resembles a pine cone or an artichoke. Adapted to eating ants and termites, P. americanus had a narrow, elongated head (Emry 2004) similar to many xenarthans (anteaters and armadillos), though research shows that the resemblance is due to convergent evolution. Fossils show that by the late Eocene, P. americanus already lacked teeth, just like extant pangolins (Emry 2004). Instead they had a long, sticky, extendable tongue for catching insects. Their short legs are equipped with long, sharp claws that are used for digging into termite mounds to expose the insects. Their backs are low and rounded, and their tails are long and also covered in scales. When threatened, pangolins curl into a ball by folding their tails over their heads, exposing only the sharp edges of their scales. Paleontologists have noted a number of more primitive characteristics in P. americanus, but these are generally detailed cranial (skull) measurements (Gaudin and Wible 1999) and would not have greatly influenced the outer appearance of the animal. Despite its total lack of teeth, P. americanus still had a more robust jaw that retained features of toothed mammals (such as a bone called a coronoid process). In fact, P. americanus has so many common features with modern pangolins that researchers have noted its failure to provide useful morphological information regarding pangolin ancestry (Emry 2004).