Ungulates are members of the diverse clade Euungulata, which primarily consists of large mammals with hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined to be a polyphyletic and thereby invalid clade based on molecular data. As a result, true ungulates had since been reclassified to the newer clade Euungulata in 2001 within the clade Laurasiatheria while Paenungulata has been reclassified to a distant clade Afrotheria. Living ungulates are divided into two orders: Perissodactyla including equines, rhinoceroses, and tapirs; and Artiodactyla including cattle, antelope, pigs, giraffes, camels, sheep, deer, and hippopotamuses, among others. Cetaceans such as whales, dolphins, and porpoises are also classified as artiodactyls, although they do not have hooves. Most terrestrial ungulates use the hoofed tips of their toes to support their body weight while standing or moving. Two other orders of ungulates, Notoungulata and Litopterna, both native to South America, became extinct at the end of the Pleistocene, around 12,000 years ago.
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology of the teeth of an animal.
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name molar derives from Latin, molaris dens, meaning "millstone tooth", from mola, millstone and dens, tooth. Molars show a great deal of diversity in size and shape across the mammal groups. The third molar of humans is sometimes vestigial.
The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position, the thumb is the outermost digit. The Medical Latin English noun for thumb is pollex, and the corresponding adjective for thumb is pollical.
Colugos are arboreal gliding mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur and the Philippine flying lemur. These two species make up the entire family Cynocephalidae and order Dermoptera.
New World monkeys are the five families of primates that are found in the tropical regions of Mexico, Central and South America: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Ceboidea, the only extant superfamily in the parvorder Platyrrhini.
Strepsirrhini or Strepsirhini is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos ("bushbabies") and pottos from Africa, and the lorises from India and southeast Asia. Collectively they are referred to as strepsirrhines. Also belonging to the suborder are the extinct adapiform primates which thrived during the Eocene in Europe, North America, and Asia, but disappeared from most of the Northern Hemisphere as the climate cooled. Adapiforms are sometimes referred to as being "lemur-like", although the diversity of both lemurs and adapiforms does not support this comparison.
The phalanges are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones.
Megaladapis, informally known as the koala lemur, is an extinct genus of lemurs belonging to the family Megaladapidae, consisting of three species that once inhabited the island of Madagascar. The largest measured between 1.3 to 1.5 m in length.
Victoriapithecus macinnesi was a primate from the middle Miocene that lived approximately 15 to 17 million years ago in Northern and Eastern Africa. Through extensive field work on Maboko Island in Lake Victoria, Kenya, over 3,500 specimens have been found, making V. macinnesi one of the best-known fossil primates. It was previously thought that perhaps multiple species of Victoriapithecus were found, however the majority of fossils found indicate there is only one species, V. macinnesi. Victoriapithecus shows similarities to the extant subfamilies Colobinae and Cercopithecinae. However, Victoriapithecus predates the last common ancestor of these two groups and instead is thought to be a sister taxon.
Notharctus tenebrosus was an early primate from the early Eocene, some 54–38 million years ago. Its fossil was found by Ferdinand V. Hayden in 1870 in southwestern Wyoming. When first found, Notharctus tenebrosus was thought to be a small pachyderm due to the concentration of pachyderm fossils in the area. However, after Walter W. Granger's discovery of a nearly complete skeleton, also in Wyoming, it was firmly established as a primate. Notharctus tenebrosus most resembles modern-day lemurs, although they are not directly related.
The Antilocapridae are a family of ruminant artiodactyls endemic to North America. Their closest extant relatives are the giraffids. Only one species, the pronghorn, is living today; all other members of the family are extinct. The living pronghorn is a small ruminant mammal resembling an antelope.
Smilodectes is a genus of adapiform primate that lived in North America during the middle Eocene. It possesses a post-orbital bar and grasping thumbs and toes. Smilodectes has a small cranium size and the foramen magnum was located at the back of the skull, on the occipital bone.
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.
Carpolestes is a genus of extinct primate-like mammals from the late Paleocene of North America. It first existed around 58 million years ago. The three species of Carpolestes appear to form a lineage, with the earliest occurring species, C. dubius, ancestral to the type species, C. nigridens, which, in turn, was ancestral to the most recently occurring species, C. simpsoni.
A toothcomb is a dental structure found in some mammals, comprising a group of front teeth arranged in a manner that facilitates grooming, similar to a hair comb. The toothcomb occurs in lemuriform primates, treeshrews, colugos, hyraxes, and some African antelopes. The structures evolved independently in different types of mammals through convergent evolution and varies both in dental composition and structure. In most mammals the comb is formed by a group of teeth with fine spaces between them. The toothcombs in most mammals include incisors only, while in lemuriform primates they include incisors and canine teeth that tilt forward at the front of the lower jaw, followed by a canine-shaped first premolar. The toothcombs of colugos and hyraxes take a different form with the individual incisors being serrated, providing multiple tines per tooth.
Sivaladapis is a genus of adapiform primate that lived in Asia during the middle Miocene.
Afradapis is a genus of adapiform primate that lived during the Late Eocene. The only known species, Afradapis longicristatus, was discovered in the Birket Qarun Formation in northern Egypt in 2009. While its geographic distribution is confined to Afro-Arabia, Afradapis belongs to the predominantly European adapiform family Caenopithecinae. This taxonomic placement is supported by recent phylogenetic analyses that recover a close evolutionary relationship between Afradapis and adapiforms, including Darwinius. While adapiforms have been noted for their strepsirrhine-like morphology, no adapiform fossil possesses the unique anatomical traits to establish an ancestor-descent relationship between caenopithecids and living strepsirrhines. It ate leaves and moved around slowly like lorises.
Carpodaptes 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.
Torrejonia is a genus of extinct plesiadapiform that belongs to the family Palaechthonidae. There are currently two species known, T. wilsoni and T. sirokyi. This genus is present in the fossil record from around 62–58 Ma. Species belonging to this genus are suggested to be plesiadapiforms based on adaptations observed in the skeletal morphology consistent with arboreal locomotor behavior. Following the mass extinction event at the Cretaceous–Paleogene boundary (K-Pg), a large diversity of plesiadapiform families were documented beginning at the Torrejonian NALMA. Research has shown that T. wilsoni is one of the largest palaechthonids and is reconstructed as being more frugivorous than other palaechthonids.
