Veliometra sehuhi n.gen., n.sp. is described from Amazonas, Brazil. It has many ptesiomorphic characters and a strong phenetic affinity with the Macroveliidae. The common occurrence of a number of apomorphic characters in the new genus and the genera of Hydrometridae makes Veliometra n.gen. a member of the hydrometrid lineage. The cladistic relationships of the genera of Hydrometridae are analysed and the division of the family into three subfamilies is supported. The proposed sister group relationship between Veliometra n.gen. from Brazil and Heterocleptes from West and Central Africa is taken as evidence of vicariance biogeography in response to continental drift. A classification and a key to subfamilies and genera of Hydrometridae are included.