| abstract | We describe four new species of feather mites of the family Gabuciniidae collected from Accipitridae and Falconidae (Falconiformes) from South and North America. Three of these belong to new genera, Metagabucinia gen. nov. with one new species and Proaposolenidia gen. nov. with two new species. We also describe one new species of the genus Aposolenidia Gaud and Atyeo. The new species and host records are Aposolenidia striata sp. nov. from the pearl kite, Gampsonyx swainsonii Vigors, Metagabucinia caracarae sp. nov. from the red-throated caracara, Ibycter americanus (Boddaert), Proaposolenidia accipitris sp. nov. from the Cooperʼs hawk, Accipiter cooperii (Bonaparte), and Proaposolenidia elanoides sp. nov. from the swallow-tailed kite, Elanoides forficatus (Linnaeus). Aposolenidia, Metagabucinia, and Proaposolenidia constitute a morphologically distinct group within the Gabuciniidae. This “Aposolenidia genus group” is characterized by the following features: bases of epimerites of legs I and II inflated, ball-shaped, heavily sclerotized, and connected by sclerotized dorsolateral bridges; tarsi of legs I and II with dorsal walls strongly thickened and dorsobasal part of tarsus I inflated. Members of this group coexist on falconiforms with other gabuciniid taxa that exhibit longer and more extensively sclerotized bodies, such as the genera Aetacarus Gaud and Atyeo, Hieracolichus Gaud and Atyeo, and Ramogabucinia Gaud and Atyeo. |