Machlydotherium

Machlydotherium is an extinct genus of cingulate of uncertain systematic affinities, perhaps belonging to the Pampatheriidae. It lived from the Middle Eocene to the Early Oligocene, and its fossilized remains were found in South America.

Description
This animal is only known from isolated osteoderms, who were large and thick, quite similar to those of the later pampatheres. Some of these osteoderms, belonging to the fixed carapace typical of many cingulates, show the start of the differentiation of secondary figures, and large central follicles. The mobile osteoderms were distinguished from those of pampatheres by a little differentiated and rough surface. A bilobed tooth, similar to those of pampatheres, but whose abrasion surface draw a cusp in the anterior section, has also been attributed to the genus Machlydotherium.

Classification
The genus Machlydotherium was first described in 1902 by Florentino Ameghino, the name itself being an anagram of Chlamydotherium, another genus of cingulates. The type species, Machlydotherium asperum, dates from the Late Eocene, but osteoderms attributed to the genus have also been found in terrains dated from the Middle Eocene to the Early Oligocene. Ameghino described several species besides the type species, such as Machlydotherium ater, M. sparsum and M. intortum, the latter now erected as its own genus, Yuruatherium.

Due to the scarcity of its remains, its antiquity and the specificities of the shape of its osteoderms, Machlydotherium can hardly be placed in a specific clade of cingulate. It seems to have been close to the pampatheres, the oldest of which only dating back from the Middle Miocene. It is possible that Machlydotherium evolved independently from the pampatheres, becoming extinct without leaving known descendants during the Oligocene.