What specialized structures on most digits allow the pygmy marmoset to grip tree trunks vertically?

Answer

Claw-shaped nails called tegulae

Most of their fingers and toes possess claw-shaped nails, known as tegulae, which enable them to grip vertical tree trunks with exceptional strength. The exception is the big toenail on each foot, which remains flat.

What specialized structures on most digits allow the pygmy marmoset to grip tree trunks vertically?
animalmammalappearancePrimatePygmy Marmoset