The first Primates
The First primates were on earth 70 million years ago. They had flexible limbs with gripping hands, and opposable digits - thumbs that can give grip. They had finger nails rather than claws, which allows protection, but does not interfere with the sensitive fingertips. They also had highly dextrous hands and agile fingers which made it easier to obtain food and allows more effective grooming. It helped to develop the use of tools.
They had flat faces and forward facing eyes which allowed stereoscopic vision. The could see in colour and judge distances, which helped them to find ripe fruit.
They also had large brains, and lived in family groups. They usually had single offspring which were dependant on their parents for a long time.