Suborder of order Primates that includes the lemurs, pottos, lorises, and galagos. Prosimians retain many ancestral traits including a postorbital bar, no fusion of the mandible or the frontal bones, a grooming claw on the second digit of the hind foot, and other traits suggestive of the primates of the Eocene; in addition prosimians have a bicornuate uterus, two pairs of mammary glands, and usually the production of more than one infant. This suborder is considered a grade and many, if not most, primatologists now subscribe to the placing the members of this group into the alternative suborder Strepsirhini (excluding the tarsiers that historically have been included in the prosimians). Many paleontologists found this latter group to be unacceptable because the defining features are soft tissue structures that are not discernible in fossils.

Cf. Anthropoidea.