Pternoconius

Pternoconius is an extinct genus of macraucheniid litoptern from the Late Oligocene and Early Miocene of Argentina. Fossils of this genus have been found in the Sarmiento Formation of Argentina.

Etymology
The genus name, Pternoconius, is an anagram of the closely related genus Coniopternium. The species name refers to the similarity of the Eocene genus Polymorphis.

Pternoconius tournoueri
In 1985, fossils found in the Early Miocene Colhué Huapí Member of the Sarmiento Formation were assigned to the genus under the name Pternoconius tournoueri, consisting of a nearly complete hemimandible.

Pternoconius bondi
In 2016 a new species of macraucheniid litoptern was described coming from the Bajada del Diablo locality in the Sarmiento Formation, consisting of the anterior portion of the skull with the maxillary region, some fragments of nasal bones, a small portion of the left zygomatic process, and most of the upper dentition (i.e., left P2–M3, right C, and right P1–M3). The species was named after Mariano Bond, in recognition of his contributions to the knowledge of South American native ungulates.

Classification
Pternoconius is a member of the subfamily Cramaucheniinae within the family Macraucheniidae. However, many studies have suggested that Cramaucheniinae is a paraphyletic group. This suggestion was further corroborated in phylogenetic analyses of the family in 2014 and 2018, which found that Cramaucheniinae is a paraphyletic group, and that Theosodon is a sister clade to the subfamily Macraucheniinae, the least primitive of the members of Cramaucheniinae.

The results of McGrath et al. 2018 are shown below.