A new subfamily, Delturinae, is described to accommodate the loricariid catfish genera Delturus Egenmann & Eigenmann, 1889 and Hemipsilichthys Eigenmann & Eigenmann, 1889, a clade recently demonstrated to be the sister group of all remaining loricariids except Lithogenes. The genus Hemipsilichthys is restricted to three species, H. gobio (Lutken, 1874), its sister species H. papillatus Pereira et al., 2000, and H. nimius Pereira et al., 2003. Relationships among species of Delturus were not resolved and a new species, D. brevis, is described from the Rio Jequitinhonha basin in eastern Brazil. The geographical distribution of Delturinae, exclusively on the south-eastern Brazilian Shield, indicates that south-eastern Brazil acts as either a refugium for basal loricariid taxa or a point of origin for the Loricariidae. Lectotypes are designated for D. parahybae Eigenmann & Eigenmann, 1889 and Plecostomus angulicauda Steindachner, 1877. Keys are presented for subfamilies of Loricariidae and for genera and species of Delturinae. Diagnoses are provided for all delturine clades and species. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society, 2006, 147, 277–299.