Twenty-seven species of Afrogamasellus Ryke and Loots and Afrodacarellits n. gen. (Acarina: Mesostigmata: Rhodacaridae) are reported from Tanzania. Ten species of Afrogamasellus, A. lyamunguensis, lootsi, itlitgitritensis, isthmits, latigynia, trimcatits, paratritncatits, fran zoides, mongii and bakeri are described as new. A. maskamensis (both sexes), tetrastigma and citri are redescribed. A new genus, Afrodacarellits, is created to include eleven new species, A. femoratiis (type species), longipodits, concavits, ngorongoroensis, pili, novembits, liipangaensis, mossi, msititni, pocsi and minitlits, plus eight species transferred from the camaxiloensis and succinctits groups of Afrogamasellits. The new genus shows some resemblance to Afrogamaselliis and Rhodacarellits, but differs from these genera in having the median tine of the tectum stalked and Y-shaped and in having a long, narrow genital shield and an elongate basal rodlike seta on tarsus I. Afrodacarelliis machadoi (Loots) and A. rnwenzoriensisn (Loots) are redescribed. Keys to species of both Afrogamasellits and Afrodacarellits are provided. In the laboratory Afrogamasellits lootsi accepted Collembola and Symphyla as prey. The enlarged first legs were not used in capture of prey. Distribution of Afrogamasellits and Afrodacarellits at various altitudes in the Uluguru Mts. of eastern Tanzania is noted. Most species occurring in the rain forest were not found at lower elevations. The largest number of individuals and species occurred in a thicket just below the forest edge. At higher elevations several species of Ajrodacarellits were common in moss. Most Afrogamasellus and Afrodacarellits appear to have relatively narrow geographic distributions. It is suggested that the large number of species of these genera in East Africa may be partly the result of an archipelago type speciation with the montane forests being comparable to islands.