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Plesiadapiformes

Adapted from Wikipedia · Discoverer experience

Fossil remains of Notharctus and Plesiadapis, two extinct primates, displayed at the Musee d'Histoire Naturelle in Brussels.

Plesiadapiformes ("Adapid-like" or "near Adapiformes") is an extinct group of early mammals that lived long ago. They are considered a basic part of the group called pan-primates, which are closely related to primates like monkeys and apes. Together with another group called Dermoptera, they form a larger group known as Primatomorpha.

The plesiadapiform Plesiadapis cookei (right), compared to Notharctus tenebrosus (left), an early crown primate. Both come from Eocene Wyoming, though the former is slightly geologically older.

Plesiadapiformes first appeared in the fossil record between 65 and 55 million years ago. Many of them went extinct by the start of the Eocene epoch. One of the most interesting things about them is that they may have been the first mammals known to have finger nails instead of claws. Scientists have studied their fossils and suggested that some Plesiadapiformes might have had gliding abilities, similar to modern colugos, based on the shape of their fingers.

Over time, scientists have debated how Plesiadapiformes fit into the family tree of life. Some believe that modern primates evolved from within this group, meaning Plesiadapiformes are not truly extinct because their descendants live today. Others think Plesiadapiformes are more closely related to Dermoptera. These discussions help scientists understand how early mammals evolved into the many primates we see today.

Images

Scientific illustration of Anagale gobiensis, an extinct mammal from the early Oligocene period, showing what this ancient relative of rodents and lagomorphs might have looked like.
Illustration of a tree shrew, a small mammal native to Southeast Asia.
An illustration of a flying fox (Cynocephalus volans), a type of fruit bat known for its ability to glide through the air.
An artist's illustration of Purgatorius unio, one of the earliest known primates from ancient North America.

Related articles

Eocene

This article is a child-friendly adaptation of the Wikipedia article on Plesiadapiformes, available under CC BY-SA 4.0.

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