Description
This animal is known from very fragmentary remains, including a partial mandible. Its relatives, the astrapotheres, vaguely resembled tapirs.
The mandibular symphysis was quite long and flat on the interior surface. it had two pairs of small incisors, framed posteriorly and a bit laterally by a pair of very strong, long-rooted, very curved and forward-protruding teeth. Behind them was a large diastema, followed by another pair of very strong teeth, slightly curved forward but with a short root. These two teeth were approximately located near the middle of the symphysis. Like Trigonostylops , the symphysis of Shecenia had a flat lower edge.
Mesonychia is an extinct taxon of small- to large-sized carnivorous ungulates related to artiodactyls. Mesonychids first appeared in the early Paleocene, went into a sharp decline at the end of the Eocene, and died out entirely when the last genus, Mongolestes, became extinct in the early Oligocene. In Asia, the record of their history suggests they grew gradually larger and more predatory over time, then shifted to scavenging and bone-crushing lifestyles before the group became extinct.
Plesiadapis is one of the oldest known primate-like mammal genera which existed about 55–58 million years ago in North America and Europe. Plesiadapis means "near-Adapis", which is a reference to the adapiform primate of the Eocene period, Adapis. Plesiadapis tricuspidens, the type specimen, is named after the three cusps present on its upper incisors.
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.
Pyrotherium is an extinct genus of South American ungulate, of the order Pyrotheria, that lived in what is now Argentina and Bolivia, during the Late Oligocene. It was named Pyrotherium because the first specimens were excavated from an ancient volcanic ash deposit. Fossils of the genus have been found in the Sarmiento Formation of Argentina and the Salla Formation of Bolivia.
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.
Astrapotheria is an extinct order of South American and Antarctic hoofed mammals that existed from the late Paleocene to the Middle Miocene, 59 to 11.8 million years ago. Astrapotheres were large and rhinoceros-like animals and have been called one of the most bizarre orders of mammals with an enigmatic evolutionary history.
Phenacodontidae is an extinct family of large herbivorous mammals traditionally placed in the “wastebasket taxon” Condylarthra, which may instead represent early-stage perissodactyls. They lived in the Paleocene and Eocene epochs and their fossil remains have been found in North America and Europe.
Astrapotherium is an extinct genus of South American mammals that vaguely resembled a small elephant or large tapir. However, it was unrelated to elephants or tapirs, but was instead related to other extinct South American ungulates. Fossils have been dated from the Early to Middle Miocene. Fossil remains of the type species A. magnus have been found in the Santa Cruz Formation in Argentina. Other fossils have been found in the Deseado, Sarmiento, and Aisol Formations of Argentina and Chile.
Astraponotus is an extinct genus of herbivorous mammals, belonging to the family of astrapotherids. It lived during the late Late Eocene and its fossil remains have been found in the Sarmiento Formation of Argentina, South America.
Azygonyx was a small tillodont mammal, likely the size of a cat to raccoon, that lived in North America during the Paleocene and Eocene in the early part of the Cenozoic Era. The only fossils that have been recovered are from the Willwood and Fort Union Formations in the Bighorn Basin of Wyoming, United States, and date to the Clarkforkian to Wasatchian, about 56 to 50 million years ago. Fifty-six collections that have been recovered thus far include the remains of Azygonyx. Azygonyx survived the Paleocene Eocene Thermal Maximum along with other mammals like Phenacodus and Ectocion, both of which were ground-dwelling mammals. Azygonyx probably was a generalist terrestrial mammal that may have roamed around the ground, but was also capable of climbing trees.
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.
Paulogervaisia is an extinct genus of mammal, belonging to the family Didolodontidae. Its fossilized remains have been found in South America.
Notoetayoa is an extinct genus of mammal, from the order Xenungulata. It lived during the Middle Paleocene, and its fossilized remains were discovered in South America.
Eoastrapostylops is an extinct genus of herbivorous mammal, who lived during the Late Paleocene in what is now South America.
Tetragonostylops is an extinct genus of mammal, related to Astrapotheria. It lived during the Late Paleocene, and its fossils were discovered in South America.
Astrapothericulus is an extinct genus of mammals, belonging to the order Astrapotheria. It lived during the Lower Miocene in what is now South America.
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.
Protolipterna is an extinct genus of mammal, belonging to the order Litopterna. It lived during the Late Paleocene and the Early Eocene, in what is now South America.
Anisolambda is an extinct genus of litoptern ungulate, belonging to the family Proterotheriidae. It lived from the Late Paleocene to the Middle Eocene in what is now South America.
Henricosbornia is an extinct genus of Notoungulate. It lived from the Late Paleocene to the Middle Eocene, in what is today South America.
