EVOLUTION × LIFE

First Primates

~55 million years ago

Phanerozoic · Cenozoic · Paleogene · Eocene

An animal of about thirty grams, the weight of a mouse, with hands that gripped, eyes facing forward and nails where its ancestors had claws. Archicebus achilles, from China, is the oldest primate skeleton anyone has found in one piece, and it was awake in daylight, living in trees and eating insects, which is not the nocturnal creature the textbooks used to assume at the base of our order.

Why it matters

Hands that grip and eyes that judge distance are the two things our order has never given up, and they were both there at thirty grams. Everything primates did later, including the parts that matter to us, was done with equipment assembled for catching insects in branches.

Dating & uncertainty

The oldest primate skeletons date to about 55 Ma, just after the Paleocene-Eocene warming. Molecular clocks and Paleocene plesiadapiform fossils suggest the lineage began earlier, but complete specimens are lacking.

Sources

1. Ni et al. (2013), Nature · The oldest known primate skeleton and early haplorhine evolution
2. Bloch et al. (2007), PNAS · New Paleocene skeletons and the relationship of plesiadapiforms to crown-clade primates

Earth history as one day

23:42:3317 min 27 s before midnight

if Earth’s 4.54 billion years were compressed into a single day