Thalassocnus

Thalassocnus is an extinct genus of apparently semiaquatic (for the geologically oldest species) or fully aquatic (for the geologically most recent species) marine sloth from the Miocene and Pliocene of South America. Fossils found to date have been from the coast of Peru (Pisco Formation) and Chile (Bahía Inglesa Formation).[1][2] They were apparently grazers of sea grass and seaweed. The various species of this genus provides the best-documented case of gradual adaptation to a secondarily aquatic lifestyle. This is documented both at the morphological level, such as a progressive flattening of the radius,[3] and at the microanatomical level, which shows a progressive increase in thickness (pachyostosis) and compactness (osteosclerosis) of the long limb bones and ribs,[4] providing ballast. They may have used their powerful claws to anchor themselves to the sea floor to facilitate feeding, similar to the behavior of the marine iguana.[3]
Category:Animals
Category:Creatures