Utaetus

Utaetus is an extinct genus of mammal in the order Cingulata, related to the modern armadillos. The genus contains a single species, Utaetus buccatus. It lived in the Middle to Late Eocene (about 40 to 36 million years ago) and its fossil remains were found in Argentina and Brazil in South America.
Description.
This animal, about long, was very similar to a modern armadillo. In particular, the appearance likely recalled that of the modern Euphractus, and it already had the typical well-developed xenarthral joints on the vertebrae. Among the other characteristics in common with the modern armadillos, "Utaetus" possessed a bony connection between the ischium and the sacrum (this structure was constituted by caudal vertebrae known as pseudosacral) and continuous-growth cylindrical teeth similar to chisels, with wear in the occlusal part. There were ten lower teeth on each side of the jaw; the first two were much smaller and are interpreted as incisors. Unlike later armadillos, however, "Utaetus" still had a varying amount of enamel on the lingual and buccal surfaces of the teeth, and the cervical vertebrae were separated (and not co-ossified). The skeleton shows that this animal was suitable for digging, as evidenced by the presence of a large acromion on the scapula and a prominent olecranon on the ulna. The posterior margin of the scapula was thickened, and formed a secondary incipient spine.
Classification.
The genus "Utaetus" was first described in 1902 by Florentino Ameghino, based on fossil remains initially thought to date back to the Cretaceous. The type species is "Utaetus buccatus", also known for cranial material, but Ameghino described further species based on fragmentary remains ("U. deustus", "U. lenis", "U. laevus", "U. laxus"), now considered "nomina dubia"."Utaetus" is considered a primitive member of the Dasipodidae, the family that includes the modern armadillos and their extinct relatives. In particular,"Utaetus" and its close relatives (such as "Parutaetus") could be closely related to the modern genus "Euphractus". The name "Utaetus" is an anagram of "Eutatus", another extinct armadillo.
Distribution.
Fossils of "Utaetus" have been found in: