Thalassocnus

Skeletal reconstruction of Thalassocnus in the Muséum national d' histoire naturelle in Paris.

• Peru
• Chile

Thalassocnus is an extinct genus of sloths. Fossils of the genus were first found later on the Pacific coast of Peru, and on the coast of Chile. The genus lived from the upper Miocene before 7.25 million years ago until the end of the Pliocene epoch 2.58 million years ago, possibly even up to 1.2 million years ago Uquium. The locations of the fossils are coastal marine deposits in which a rich fauna of marine vertebrates such as whales, dolphins, seabirds, crocodiles, bony fish, sharks and rays, but except for the sloths no remains other land mammals have been found. This, as well as the morphology of the premaxillary bone ( premaxilla ), the proportions of the legs and the similarity of the caudal vertebrae suspect leave with those of beavers and otters that Thalassocnus aquatic lived and probably similar to the marine iguanas of the Galapagos islands appeared in the sea to sea grasses and algae eat. Maybe Thalassocnus occupied the ecological niche of the living at the same time North Pacific Desmostylia on the Pacific coast of South America.

Features

The skull of Thalassocnus was 30 cm long. The Zwischenkieferbein was tall, ruggedly built and extended. It probably served as a support for well-developed lips, with which the animals could graze like manatees seagrass and algae. Thalassocnus had no canines. From the side saw the profile of the frontal bone is relatively straight, as in Nothrotherium and Pronothotherium.

The first finger of the first finger bone is missing, the first and second phalanges of the third finger are grown together. The second, third and fourth fingers are provided with very strong claws, the first finger with a kind of hoof. Directed away from the center of the body end of the femur is narrower than the body-facing end. In comparison to the femoral tibia is longer than other nothrotheiiden sloth. The outermost vertebrae of the tail had forked apertured transverse processes. Maybe the tail was used for swimming.

Species

So far, five species have been described:

• Thalassocnus antiquus, late Miocene.
• Thalassocnus natans, ( type species ), late Miocene.
• Thalassocnus littoralis, early Pliocene.
• Thalassocnus carolomartini, late Pliocene.
• Thalassocnus yaucensis, late Pliocene.

The three stratigraphically older types of Thalassocnus ( T. antiquus, T. natans, and T. littoralis ) fed on sea grass or possibly from angespültem only went into shallow water where the depth was less than a meter. Your back teeth show wear and tear by the friction of sand grains. The two younger Thalassocnus species ( T. and T. carolomartini yaucensis ) ate the other hand, in deeper water, their teeth are missing, the wear grooves.