Description
This animal is only known from a fragment of its jaw, and it is therefore impossible to precisely reconstruct its appearance. From a comparison with a similar but better known animal, Carodnia , it is possible that Notoetayoa was an animal with heavy shapes and a powerful body. The size of Notoetayoa was in any cases smaller than that of Carodnia, and it is possible that it was as large as a small tapir.
The lower third molar had a higher trigonid than the thalonid, and the paraconid was well defined, and not fused with the metaconid. Compared to its relative Etayoa , its metachristid was short, and the precingulid was more robust than in Etayoa and Carodnia. The talonid basin wasn't open lingually as in Carodnia, but closed as in Etayoa. The hypoconid and the hypoconulid were distinct and united by a low and rounded postmetacristid. The entoconid was crenulated and mesially projected towards the distal-lingual side of the metoconid. The distal root under the talonid was not vertical as in Carodnia but oblique to the mesial one.
Sparassodonta is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now thought to be a separate side branch that split before the last common ancestor of all modern marsupials. A number of these mammalian predators closely resemble placental predators that evolved separately on other continents, and are cited frequently as examples of convergent evolution. They were first described by Florentino Ameghino, from fossils found in the Santa Cruz beds of Patagonia. Sparassodonts were present throughout South America's long period of "splendid isolation" during the Cenozoic; during this time, they shared the niches for large warm-blooded predators with the flightless terror birds. Previously, it was thought that these mammals died out in the face of competition from "more competitive" placental carnivorans during the Pliocene Great American Interchange, but more recent research has showed that sparassodonts died out long before eutherian carnivores arrived in South America. Sparassodonts have been referred to as borhyaenoids by some authors, but currently the term Borhyaenoidea refers to a restricted subgroup of sparassodonts comprising borhyaenids and their close relatives.
Pyrotheria is an order of extinct meridiungulate mammals. These mastodon-like ungulates include the genera Baguatherium, Carolozittelia, Colombitherium, Griphodon, Propyrotherium, Proticia, and Pyrotherium.
Xenungulata is an order of extinct and primitive South American hoofed mammals that lived from the Late Paleocene to Early Eocene. Fossils of the order are known from deposits in Brazil, Argentina, Peru, and Colombia. The best known member of this enigmatic order is the genus Carodnia, a tapir-like and -sized animal with a gait similar to living African elephants.
Altanius is a genus of extinct primates found in the early Eocene of Mongolia. Though its phylogenetic relationship is questionable, many have placed it as either a primitive omomyid or as a member of the sister group to both adapoids and omomyids. The genus is represented by one species, Altanius orlovi, estimated to weigh about 10–30g from relatively well-known and complete dental and facial characteristics.
Carodnia is an extinct genus of South American ungulate known from the Early Eocene of Brazil, Argentina, and Peru. Carodnia is placed in the order Xenungulata together with Etayoa and Notoetayoa.
Ambondro mahabo is a mammal from the Middle Jurassic (Bathonian) Isalo III Formation of Madagascar. The only described species of the genus Ambondro, it is known from a fragmentary lower jaw with three teeth, interpreted as the last premolar and the first two molars. The premolar consists of a central cusp with one or two smaller cusps and a cingulum (shelf) on the inner, or lingual, side of the tooth. The molars also have such a lingual cingulum. They consist of two groups of cusps: a trigonid of three cusps at the front and a talonid with a main cusp, a smaller cusp, and a crest at the back. Features of the talonid suggest that Ambondro had tribosphenic molars, the basic arrangement of molar features also present in marsupial and placental mammals. It is the oldest known mammal with putatively tribosphenic teeth; at the time of its discovery it antedated the second oldest example by about 25 million years.
Utaetus is an extinct genus of mammal in the order Cingulata, related to the modern armadillos. The genus contains two species, Utaetus buccatus and U. magnum. It lived in the Late Paleocene to Late Eocene and its fossil remains were found in Argentina and Brazil in South America.
Prosotherium is an extinct genus of hegetotheriid notoungulate. It lived during the Late Oligocene, and its fossilized remains were found in South America.
Ernestokokenia is an extinct genus of mammal, belonging to the Didolodontidae. It lived during the Early Eocene and the Middle Eocene, and its fossils were discovered in South America.
Lamegoia is an extinct genus of mammals, belonging to the family Didolodontidae. It contains a single species, Lamegoia conodonta, which lived during the Late Paleocene in what is now South America.
Paulogervaisia is an extinct genus of mammal, belonging to the family Didolodontidae. Its fossilized remains have been found in South America.
Rodcania is an extinct genus of mammal, belonging to the order Xenungulata. It contains a single species, Rodcania kakan, which lived during the Paleocene. Its remains were found in South America. The genus name is an anagram of Carodnia.
Asmithwoodwardia is an extinct genus of mammals, from the order Litopterna. It lived during the Late Paleocene and the Early Eocene, and its fossilized remains were found in South America.
Proadiantus(Ameghino, 1897) is an extinct genus of adianthid litoptern. It lived during the Late Oligocene, in what is today South America. It consists of only 1 species, Proadiantus excavatus.
Henricosbornia is an extinct genus of henricosborniid notoungulate that lived from the Late Paleocene to the Middle Eocene of what is now Argentina and Brazil.
Transpithecus is an extinct genus of Notoungulates, belonging to the suborder Typotheria. It lived during the Middle Eocene in what is today South America.
Isotemnus is an extinct genus of notoungulate belonging to the family Isotemnidae. It lived from the Late Paleocene to the Middle Eocene of what is now Argentina.
Teratopithecus is an extinct genus of archaeopithecid notoungulate that lived during the Middle Eocene of what is now Argentina. Fossils of this genus have been found in the Sarmiento Formation of Argentina.
Archaeogaia is an extinct genus of notoungulates that lived during the Early and Middle Paleocene of what is now Argentina. It is one of the oldest known unequivocal notoungulates.
Namafelis is an extinct genus of felids that lived in what is now Namibia during the Early Miocene. It contains a single species, Namafelis minor. Closely related to Diamantofelis, it is of “Pseudaelurus-grade”, and therefore a rather basal member of the cat family.
