A new genus, Prodysderina, is established for a group of Neotropical oonopids belonging to the Dysderina complex and characterized by having a laterally incised, tuberculate, but unridged sternum, a groove connecting the posterior (but not the anterior) spiracles, and a male embolus with an elongated distal prong and a reduced proximal prong. Dysderina armata Simon is transferred to Prodysderina and selected as the type species; eight new species are described from Venezuela (P. megarmata, P. rollardae, P. janetae) and Colombia (P. piedecuesta, P. rasgon, P. santander, P. filandia, P. otun). The genus Aschnaoonops contains species that resemble those of Prodysderina but have a twisted (and usually basally widened) embolus in males, and a reduced genital atrium in females. That genus occurs in the Andes from Peru north to Colombia, east across northern South America, and north into the West Indies. Dysderina similis (Keyserling) and D. propinqua (Keyserling) from Colombia, and D. simla Chickering from Trinidad, are transferred to Aschnaoonops, and females of the two Keyserling species are described for the first time. One new species, A. silvae, has been taken by canopy fogging and appears to be widespread in the Amazonian portions of Peru, Ecuador, and Colombia. A total of 36 other new, ground-dwelling, microdistributed species are described: A. yasuni, A. tiputini, A. cosanga, A. ramirezi, A. jatun, and A. marshalli from Ecuador, A. leticia, A. orito, A. pira, A. paez, A. huila, A. meta, A. alban, A. chingaza, A. pamplona, A. pedro, and A. marta from Colombia, A. chorro, A. indio, A. tachira, A. tariba, A. teleferico, A. jaji, A. merida, A. aquada, A. masneri, A. trujillo, A. cristalina, A. bocono, A. simoni, and A. margaretae from Venezuela, A. malkini, A. caninde, and A. belem from Brazil, A. villalba from Puerto Rico, and A. gorda from the Virgin Islands. Another new genus, Bidysderina, is established for a group of species resembling those above in sternal structure but having differently constructed male palps; five new species (