Protolipterna

Protolipterna is an extinct genus of mammal, belonging to the order Litopterna. It lived during the Late Paleocene and the Early Eocene, in what is now South America.

Description
It was a small-sized animal, not exceeding 35 centimeters in length ; it weighed approximately one kilogram. It had a compact body and elongated and slender legs. Its general appearance was comparable to that of a modern chevrotain. Its dentition possessed low-crowned brachyodont and bunodont molars, but it also had long upper fang-shaped canines, not unlike today's chevrotains. Its legs, elongated and slender, suggest a digitigrade gait, unlike its contemporaries, such as Colbertia, which were plantigrades.

Classification
Prtolitopterna ellipsodotoides was first described by Cifelli in 1983, based on fragmentary mandible preserving teeth, found in the Itaboraí Formation of Brazil, in terrains dated from the end of the Paleocene or the Early Eocene. Several other fossils were later found, making it possible to reconstruct its appearance and affinities.

Protolipterna was a basal litoptern, a clade of mammals that diversified in South America during the Cenozoic. Protolipterna is the eponymous genus of Protolipternidae, a possibly paraphyletic family including some of the most basal members of Litopterna. The name Protolipterna is an anagram of Litopterna coupled with the prefix proto-, "first". One of the close relatives of this genus was Asmithwoodwardia.

Paleoecology
Studies of the postcranial skeleton of Protolipterna allows to hypothesize that this animal, with its long digitigrade legs, was able to run quickly and to jump. Its bunodont molars were ideal for the consumption of tender foliage. It is unclear whether the long upper canines were a feature affecting only of the two sexes.