The genus Carlogonus Demange, 1961, is diagnosed, and its relationship with other members of the Harpurostreptini Hoffman, 1980 is discussed. A new species, Carlogonus gayathri sp. nov. is described and illustrated from the southern Indian State of Kerala, and its DNA barcoding data is presented. Phylogenetic analysis based on mtDNA sequence data revealed that Carlogonus is sister-taxon to Thyropygus Pocock, 1894. Two species-groups are recognised in Carlogonus: the exaratus-group is characterised by a single tibial spine on the gonopod, while the acifer-group has paired tibial spines. A dichotomous key is presented for the known Carlogonus spp., and the current distribution of the genus is mapped.