Mesodma is an extinct genus of mammal, a member of the extinct order Multituberculata within the suborder Cimolodonta, family Neoplagiaulacidae. It lived during the upper Cretaceous and Paleocene Periods of what is now North America. The earliest definitive record is from the late Santonian stage strata of the Straight Cliffs Formation. A single premolar tooth from the lower Cenomanian stage strata of the Cedar Mountain Formation has been tentatively assigned to this genus based on its similarity, but its describers noted that it is unlikely that Mesodma lived during that time.
Purgatorius is a genus of seven extinct eutherian species typically believed to be the earliest example of a primate or a proto-primate, a primatomorph precursor to the Plesiadapiformes, dating to as old as 66 million years ago. The first remains were reported in 1965, from what is now eastern Montana's Tullock Formation, specifically at Purgatory Hill in deposits believed to be about 63 million years old, and at Harbicht Hill in the lower Paleocene section of the Hell Creek Formation. Both locations are in McCone County, Montana.
Mesonychia is an extinct taxon of small- to large-sized carnivorous ungulates related to artiodactyls. Mesonychians 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.
Miacis is an extinct genus of placental mammals from clade Carnivoraformes, that lived in North America from early to middle Eocene.
Chriacus is an extinct genus of placental mammals that lived in what is now North America during the Paleocene epoch and died out after the early Eocene. In life, members of the genus would have looked something like a kinkajou or binturong, though they were not closely related to any living mammal. Well preserved fossils allow clear information on what they looked like. They were about 1 metre (3.3 ft) long including a long, robust tail, which may or may not have been prehensile. Other features include a light build, weighing approximately 7 kg (15 lb), and many adaptations typical of animals that live in trees. These include walking on the soles of their five-toed feet, and having long, curved, compressed claws. The powerfully built limbs had flexible joints, especially the ankles, an adaptation that allows an animal to turn its hind feet behind it, like modern tree squirrels, in order to climb downward. They were probably omnivores, eating fruit, eggs, insects and small mammals.
Protungulatum is an extinct genus of eutherian mammals within extinct family Protungulatidae, and is possibly one of the earliest known placental mammals in the fossil record, that lived in North America from the Late Cretaceous to early Paleocene.
Oxyaena is an extinct genus of placental mammals from extinct subfamily Oxyaeninae within extinct family Oxyaenidae, that lived in Europe, Asia and North America during the early Eocene.
Ernanodon is an extinct genus of placental mammal from extinct family Ernanodontidae within extinct order Palaeanodonta, that lived from the middle to late Paleocene in China and Mongolia.
Triisodontidae is an extinct, probably paraphyletic, or possibly invalid family of mesonychian placental mammals. Most triisodontid genera lived during the Paleocene in North America, but the genus Andrewsarchus is known from the middle Eocene of Asia. Triisodontids were the first relatively large predatory mammals to appear in North America following the extinction of the non-bird dinosaurs. They differ from other mesonychian families in having less highly modified teeth.
The Fort Union Formation is a geologic unit containing sandstones, shales, and coal beds in Wyoming, Montana, and parts of adjacent states. In the Powder River Basin, it contains important economic deposits of coal, uranium, and coalbed methane.
Vassacyon is an extinct genus of placental mammals from clade Carnivoraformes, that lived in North America and Europe from the late Paleocene to early Eocene. It is considered the largest of the early Eocene mammals.
Raphictis is an extinct genus of placental mammals from extinct subfamily Didymictinae within extinct family Viverravidae, that lived in North America during late Paleocene.
Tillodontia is an extinct suborder of eutherian mammals known from the Early Paleocene to Late Eocene of China, the Late Paleocene to Middle Eocene of North America where they display their maximum species diversity, the Middle Eocene of Pakistan, and the Early Eocene of Europe. Leaving no descendants, they are most closely related to the pantodonts, another extinct group. The tillodonts were medium- to large-sized animals that probably feed on roots and tubers in temperate to subtropical habitats.
Hyopsodontidae is an extinct family of primitive mammals initially assigned to the order Condylarthra, living from the Paleocene to the Eocene in North America and Eurasia. Condylarthra is now thought to be a wastebasket taxon; hyopsodontids have occasionally been speculated to be related to Afrotheria, but the most recent consensus is that they are related to Perissodactyla. Analysis of the inner ear shows shared characteristics with the Equoidea ; they may be a basal ungulate group near to perissodactyls.
Triisodon is a genus of extinct mesonychian mammal that existed during the Early Paleocene of New Mexico, North America. The genus was named by Edward Drinker Cope in 1881 as a member of the Acreodi, a now invalid taxon that encompassed both creodonts and mesonychians. The premolar teeth have three points, hence the generic name. Cope described the type specimen of T. quivirensis as "about the size of a wolf." A smaller species has also been identified from the same region. Since material from this genus is incomplete, the exact size of adults and whether they showed sexual dimorphism or regional variations in size is unknown.
This paleomammalogy list records new fossil mammal taxa that were described during the year 2011, as well as notes other significant paleomammalogy discoveries and events which occurred during that year.
Altacreodus is an extinct genus of eutherian mammals. Fossils have been found in North America where they first appeared during the Late Cretaceous, and they died out prior to the start of the Paleocene. It is possibly one of the earliest known placental mammals in the fossil record.
Protictis is an extinct paraphyletic genus of placental mammals from extinct subfamily Didymictinae within extinct family Viverravidae, that lived in North America from early Paleocene to middle Eocene.
Gypsonictops is an extinct genus of leptictidan mammals of the family Gypsonictopidae, which was described in 1927 by George Gaylord Simpson. Species in this genus were small mammals and the first representatives of the order Leptictida, that appeared during the Upper Cretaceous.
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.
