Meanings of early primates in English

The early primates somehow had to cross open water in order to colonise Africa.

Natural selection favored those mutations that helped early primates adapt to walking upright because standing up conferred benefits in this particular habitat.

Alligators, tortoises, early primates, tapirs, and other creatures representative of milder climates lived in this place, but just how warm was it?

The early primates from which Lucy evolved, the ones forced out onto the savanna, lived in casual bands of up to fifty members.

Early primates, for example, hunt by sight rather than by scent.