Two new monotypic genera and one new species, Afrodialox dimorphopalpalis n. gen. & n. sp. (Diptilomiopidae: Diptilomiopinae) and Borassia borassis (Mohanasundaram, 1981) n. gen. & n. comb. (Phytoptidae: Phytoptinae), are described from Hyphaene coriacea (Arecaceae) from South Africa. A. dimorphopalpalis n. sp. is sexually dimorphic with respect to palptarsal appendages, whereas Novophytoptus (Phytoptidae: Novophytoptinae) is sexually dimorphic with respect to empodial shape. These are rare examples of pronounced sexual dimorphism in Eriophyoidea. Three monotypic diptilomiopine genera living on palms (Dialox, Neodialox and Afrodialox n. gen.) form a putatively monophyletic group, "Dialox-like diptilomiopines" (DD). Hypotheses on the origin of this group are discussed in the context of paleobiography of palms and their phylogenetic relationships with eriophyoids from herbaceous monocots. The preferred hypothesis implies the following sequence of events: (a) South American origin of DD on attaleine palms (Areceae: Cocoseae) in the Paleocene; (b) migration to Indian Ocean, a host shift to borassoid palms (Coryphoideae: Borasseae), and divergence in India and Africa during the Eocene; and (c) human mediated introduction from Malesia to Latin America with coconut during the Pleistocene. Well-resolved deep phylogenies of Arecaceae published by botanists in recent years provide an excellent background for future cophylogenetic studies of the system Eriophyoidea-Arecaceae, inviting researchers (especially those from tropical countries with rich palm diversity) to use palm inhabiting eriophyoids as a model group for tracing steps of the evolution of Eriophyoidea on plants.