Abstract
The genus Linepithema was erected by Mayr (1866) for his male-based species L.fuscum. In this study a new species is described also based on male morphology, L.paulistanasp. nov., collected in the city of São Paulo, Brazil, which is attributed to the fuscum group (Formicidae: Dolichoderinae). Linepithemapaulistanasp. nov. is the only species of fuscum group present in the eastern part of South America. It is easily distinguishable from the other species of the group because of the presence of a triangular volsellar tooth, which is distally situated between the digitus and the basivolsellar process. By using SEM and optical microscopy, the external genitalia of L.paulistanasp. nov. were analyzed and illustrated and some characters and previous interpretations have been re-evaluated in the Linepithemafuscum group. The male external genitalia are also comparatively analyzed in three species representative of the three Linepithema species groups, those of fuscum, humile, and neotropicum. The present work confirms that the morphological characters of male ants, especially those of male external genitalia, are effective for the identification of genera or species. Given the discrete morphological differences between the external genitalia of the fuscum group and the other species of this genus, a re-evaluation of the generic status of Linepithema is suggested.