Defining traits that make humans primates. Primates have large forward-facing eyes and larger than average brains Primates have a post-orbital bar - eye socket fully encased in bone Primates have low-crowned, broad-based bulbous posterior teeth
What makes a primate? Forward-facing eyes for depth perception, a post-orbital bar or complete post-orbital closure (bony ring or full enclosure behind the eye), broad-based posterior teeth, diverging thumbs and big toes, and flat nails instead of claws. These shared traits define our entire primate family. 🐒
Key facts claimed:
- Primates have forward-facing eyes for depth perception
- Primates have a post-orbital bar (strepsirrhines) or complete post-orbital closure (haplorhines) — not all primates have fully encased eye sockets
- Primates have broad-based posterior teeth
- Primates have diverging thumbs and big toes, with friction pads on hands and feet
- Primates have nails instead of claws — flattened distal digits on fingers and toes
Key Facts
- Primates have large forward-facing eyes and larger than average brains
- Primates have a post-orbital bar - eye socket fully encased in bone
- Primates have low-crowned, broad-based bulbous posterior teeth
- Primates have diverging thumbs and big toes, fleshy pads on hands and feet
- Primates have nails instead of claws - flattened distal flanges on fingers and toes
- These traits are synapomorphies - derived shared traits among all primates
- Tree shrews show convergent evolution with some primate traits
Source: Who was our ancestor when the dinosaurs died? by Stefan Milo