Pedinorhis stirpsarcana, an enigmatic new genus and species of emberizine finch, is known from four cave deposits of probable Wisconsinan age in central Puerto Rico. The most distinctive feature of this bird is the broad, flat ridge of the rostrum.Pedinorhisrepresents a group unknown in the Antilles and, although of uncertain affinities, somewhat resembles the mainland generaAtlapetesandPipilo. The disappearance ofPedinorhismay be related to the postglacial loss of arid, savanna-like habitats that caused the extinction, or contraction in range, of many xerophilous vertebrates in the West Indies.