Adapiformes in the context of "Plesiadapiform"

Strepsirrhini or Strepsirhini (/ˌstrɛpsəˈraɪni/ ; STREP-sə-RY-nee) 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.

Plesiadapiformes ("Adapid-like" or "near Adapiformes") is an extinct basal pan-primates group, as sister to the rest of the pan-primates. The pan-primates together with the Dermoptera form the Primatomorpha. Purgatorius may not be a primate as an extinct sister to the rest of the Dermoptera or a separate, more basal stem pan-primate branch. Even with Purgatorius removed, the crown primates may even have emerged in this group.

Plesiadapiformes first appear in the fossil record between 65 and 55 million years ago, although many were extinct by the beginning of the Eocene. They may be the earliest known mammals to have finger nails in place of claws. In 1990, K.C. Beard attempted to link the Plesiadapiformes with the order Dermoptera. They proposed that paromomyid Phenacolemur had digital proportions of the fossil indicated gliding habits similar to that of colugos.

Prosimians are a group of primates that includes all living and extinct strepsirrhines (lemurs, lorisoids, and adapiforms), as well as the haplorhine tarsiers and their extinct relatives, the omomyiforms, i.e. all primates excluding the simians. They are considered to have characteristics that are more "primitive" (ancestral or plesiomorphic) than those of simians (monkeys, apes, and humans).

Simians emerged within the Prosimians as sister group of the haplorhine tarsiers, and therefore cladistically belong to this group. Simians are thus distinctly closer related to tarsiers than lemurs are. Strepsirrhines bifurcated some 20 million years earlier than the tarsier–simian bifurcation. However, simians are traditionally excluded, rendering prosimians paraphyletic. Consequently, the term "prosimian" is no longer widely used in a taxonomic sense, but is still used to illustrate the behavioral ecology of tarsiers relative to the other primates.

Plesiadapis is one of the oldest known primate-like mammal genera which existed about 58-55 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.

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.

Notharctus tenebrosus belonged to an extinct primate group known as Adapiformes and fossils have been found in North America. Adapiform primates were among the first primates to exhibit a set of adaptations for life in the trees, such as grasping hands, binocular vision, and flexible backs. In addition to this, small orbits in the genera indicate that they were diurnal.