All species are found in the Neotropics except the speckled piculet (Picumnus innominatus) that has a wide distribution in China, India and Southeast Asia.

Species limits in this genus are doubtful, and the rate of interbreeding is "inordinately high" (Remsen et al. 2007).

As defined by Winkler and Christie (2002), it contains the 27 species listed below, all from the Neotropics except the speckled piculet, which is Asian (and sometimes placed in a monotypic genus, Vivia).

Their upperparts are brownish, greyish or olive, in some species with darker barring or white or yellowish spotting on the mantle.

They have black crowns with red, orange, or yellow marks in the male and white dots in the female, except that the male speckled piculet has brown crown marks and the female lacks white dots.