Plesiadapiformes in the context of "Claw"

Tarsiiformes /ˈtɑːrsi.ɪfɔːrmiːz/ are a group of primates that once ranged across Europe, northern Africa, Asia, and North America, but whose extant species are all found in the islands of Southeast Asia. Tarsiers (family Tarsiidae) are the only living members of the infraorder; other members of Tarsiidae include the extinct Tarsius eocaenus from the Eocene, and Tarsius thailandicus from the Miocene. Two extinct genera, Xanthorhysis and Afrotarsius, are considered to be close relatives of the living tarsiers, and are generally classified within Tarsiiformes, with the former grouped within family Tarsiidae, and the latter listed as incertae sedis (undefined). Omomyids are generally considered to be extinct relatives, or even ancestors, of the living tarsiers, and are often classified within Tarsiiformes.

Other fossil primates, including Microchoeridae, Carpolestidae, and Eosimiidae, have been included in this classification, although the fossil evidence is debated. Eosimiidae has also been classified under the infraorder Simiiformes (with monkeys and apes), and most experts now consider Eosimiidae to be stem simians. Likewise, Carpolestidae is often classified within the order Plesiadapiformes, a very close, extinct relative of primates.

This is a list of fossil primates—extinct primates for which a fossil record exists. Primates are generally thought to have evolved from a small, unspecialized mammal, which probably fed on insects and fruits. However, the precise source of the primates remains controversial and even their arboreal origin has recently been questioned. As it has been suggested, many other mammal orders are arboreal too, but they have not developed the same characteristics as primates. Nowadays, some well known genera, such as Purgatorius and Plesiadapis, thought to be the most ancient primates for a long time, are not usually considered as such by recent authors, who tend to include them in the new order Plesiadapiformes, within superorder Euarchontoglires. Some, to avoid confusions, employ the unranked term Euprimates, which excludes Plesiadapiformes. That denomination is not used here.

There is an academic debate on the time the first primates appeared. One of the earliest probable primate fossils is the problematic Altiatlasius koulchii, perhaps an Omomyid, but perhaps a non-Primate Plesiadapiform, which lived in Morocco, during the Paleocene, around 60 Ma. However, other studies, including molecular clock studies, have estimated the origin of the primate branch to have been in the mid-Cretaceous period, around 85 Ma, that is to say, in the time previous to the extinction of dinosaurs and the successful mammal radiation. Nevertheless, there seems to be a consensus about the monophyletic origin of the order, although the evidence is not clear.

Carpolestidae is a family of primate-like Plesiadapiformes that were prevalent in North America and Asia from the mid Paleocene through the early Eocene. Typically, they are characterized by two large upper posterior premolars and one large lower posterior premolar. They weighed about 20-150g, and were about the size of a mouse. Though they come from the order, Plesiadapiformes, that may have given rise to the primate order, carpolestids are too specialized and derived to be ancestors of primates.

Historically, the almost twenty species included within the family were thought to have given rise to each other over time in a linear and straightforward manner. Still today it is widely assumed that Elphidotarsius from the mid to late Paleocene gave rise to Carpodaptes which lived in the late Paleocene and subsequently gave rise to Carpolestes from the early Eocene. As a result, they have been used as biostratigraphic indicators in a variety of paleontological digs. However, the phylogenetic picture has been complicated by the discovery in Asia of both ancestral and derived carpolestids in the same stratigraphic layer.

Purgatorius is a genus of seven extinct eutherian species typically believed to be the earliest example of a primate or protoprimate, a primatomorph precursor to the Plesiadapiformes, dating to as old as 66 million years ago. The first remains (P. unio and P. ceratops) were reported in 1965, from what is now eastern Montana's Tullock Formation (early Paleocene, Puercan), specifically at Purgatory Hill (hence the animal's name) 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.

They have also been found in the Ravenscrag Formation and widely discovered in the early Paleocene Bug Creek Group, along with leptictids. These deposits were once thought to be late Cretaceous, but it is now clear that they are Paleocene channels with time-averaged fossil assemblages. It is thought to have been rat-sized (6 in (15 cm) long and 1.3 ounces (about 37 grams)) and a diurnal insectivore, which burrowed through small holes in the ground. In life, it would have resembled a squirrel or a tree shrew (most likely the latter, given that tree shrews are one of the closest living relatives of primates, and Purgatorius is considered to be the progenitor to primates). The oldest remains of Purgatorius date back to ~65.921 mya, or between 105 thousand to 139 thousand years after the K-Pg boundary.

Altiatlasius is an extinct genus of mammal, which may have been the oldest known primate, dating to the Late Paleocene (c.57 ma) from Morocco. The only species, Altiatlasius koulchii, was described in 1990.

Its true taxonomic position remains controversial. It has also been suggested that it should be classified as a plesiadapiform (an extinct group of arboreal mammal thought to be ancestral to primates) or that it should be recognized as a euprimate, either as an omomyid (a branch of fossil primates thought to be closely related to tarsiers), an early tarsiiform, or the oldest stem simian (monkeys and apes).

Carpodaptes ("fruit eater" from Ancient Greek κᾰρπός (karpós), "fruit, grain" + δᾰ́πτης (dáptēs), "eater, consumer") was a genus that encompassed small, insectivorous animals that roamed the Earth during the Late Paleocene. Specifically, Carpodaptes can be found between the Tiffanian and Clarkforkian periods of North America. Although little evidence, this genus may have made it through to the early Eocene. They are known primarily from collections of jaw and teeth fragments in North America, mainly in southwestern Canada and northwestern America. Carpodaptes are estimated to have weighed approximately 53-96 grams which made them a little bigger than a mouse. However small, Carpodaptes was a placental mammal within the order Plesiadapiformes that appeared to have a high fiber diet. This insect-eating mammal may have been one of the first to evolve fingernails in place of claws. This may have helped them pick insects, nuts, and seeds more easily off the ground than with paws or claws. Carpodaptes was thought to only exist in North America but recent discoveries of dentition fragments have been found in China.