The dark sac spiders of the genus Cetonana Strand, 1929 (Corinnidae: Trachelinae) of the Afrotropical Region are revised. Following a detailed comparison of the somatic and genitalic morphology of the Afrotropical C. martini (Simon, 1897) with the European type species, C. laticeps (Canestrini, 1868), Afroceto gen. n. is established to include the transfer of two Afrotropical species previously described in Cetonana, namely A. martini (Simon, 1897) comb. n. (type species) and A. coenosa (Simon, 1897) comb. n. Three species are proposed as junior synonyms of A. martini, namely C. curvipes (Tucker, 1920) syn. n., C. tridentata (Lessert, 1923) syn. n. and C. simoni (Lawrence, 1942) syn. n. The type of C. aculifera (Strand, 1916) from Madagascar is presumed destroyed and this species is considered nomen dubium. Additionally, 12 new Afroceto gen. n. species are described from southern Africa, namely A. arca sp. n., A. bulla sp. n., A. bisulca sp. n., A. capensis sp. n., A. corcula sp. n., A. croeseri sp. n., A. flabella sp. n., A. gracilis sp. n., A. plana sp. n., A. porrecta sp. n., A. rotunda sp. n. and A. spicula sp. n. Afroceto gen. n. species display variable ecological preferences, occurring in tree canopies, lower foliage strata, bark, and on the ground in contrasting habitats (forests, savannah, grassland, karoo and fynbos) in southern Africa, with single records from Malawi and Tanzania. Patelloceto gen. n., closely resembling Afroceto gen. n. but distinguished by the reduced leg spination and distinctive genitalic morphology, is also described, with three new species, P. secutor sp. n. (type species), P. denticulata sp. n. and P. media sp. n. from southern, central and east Africa. Patelloceto gen. n. species are primarily arboreal, occurring in tree canopies, lower foliage strata or on bark in forests and savannahs.