( pro-sim ee-eye)According to the traditional taxonomic system, one of two suborders of order Primates (the other suborder is Anthropoidea). Prosimians are the more primitive of the two suborders in that they retain features of some of the oldest primate fossils. Many lack color vision, are nocturnal, and have limited opposability of the thumb.

not used in all classifications; in some classifications considered coextensive with the Lemuroidea; in others includes both Lemuroidea and Tarsioidea