A new species of Carlogonus Demange, 1961 from southern India (Spirostreptida Harpagophoridae, Harpagophorinae), with phylogenetic analysis and speciesgroup divisions in the genus Author Sankaran, Pradeep M. Division of Arachnology, Department of Zoology, Sacred Heart College, Thevara, Cochin, Kerala 682 013, India. Author Sebastian, Pothalil A. 0000-0002-4936-4310 Division of Arachnology, Department of Zoology, Sacred Heart College, Thevara, Cochin, Kerala 682 013, India. & drpothalil @ rediffmail. com; https: // orcid. org / 0000 - 0002 - 4936 - 4310 drpothalil@rediffmail.com text Zootaxa 2020 2020-10-23 4868 1 27 40 journal article 9022 10.11646/zootaxa.4868.1.2 a5c421db-9d17-4a25-9431-378a79f940bc 1175-5326 4417203 B869EB5E-073D-471D-A9F3-D390D57B25E6 Genus Carlogonus Demange, 1961 Carlogonus Demange, 1961: 232 . Type species. Thyropygus subvalidus Carl, 1941 , by original designation. Diagnosis. Moderately large to large-sized millipedes (60–150), with a prominent, acute caudal spine, evenly curved downwards. Antero-lateral border of collum abruptly sinuate. Sternite of gonopod short with globular posterior parts. Anterior coxal fold lamelliform with modifications on the lateral margin and an antero-mesal hook-like process. Mesal margin of posterior coxal fold internally folded (towards back) to lie between the anterior coxal fold and telopodite. Telopodite strongly spiralled with unbranched palette, with femoral and tibial spines. Palette with blepharochaetae ( Attems 1936 : fig. 78e–g, Carl 1941 : figs 143–147, 149–150, Demange 1977a : figs 2–5; 1977b: figs 1–8; 1981: figs 14–15, 18; 1983: figs 11–15 and herein Figs 2 A–B, 3A, C, E, M–N, 5A–D, 7A–H, 8A–H). Carlogonus species can be distinguished from the species of Gnomognathus by the presence of an unbranched palette of telopodite and single/paired, long/short, slightly curved/straight tibial spines ( Gnomognathus species have a gonopod telopodite with a branched/unbranched palette and single/more than one, short tibial spines); from the species of Harpurostreptus by the modified lateral margin of anterior coxal fold, telopodite with tibial spine and the absence of short median spines on the inner surface of the telopodite ( Harpurostreptus species lack modifications on the lateral margin of the anterior coxal fold and the tibial spine on the telopodite and instead possess short median spines on the inner surface of the telopodite); from the species of Janardananeptus by the short sternite of the gonopod, weak indentations on the lateral margin of the anterior coxal fold and the telopodite with an unbranched palette ( Janardananeptus species have long sternite of the gonopod, deep indentations on the lateral margin of the anterior coxal fold and a branched palette); and from the species of Organognathus by the absence of an antero-mesal spine-like modification on the posterior coxal fold and an unbranched palette of the telopodite ( Organognathus species have a strong antero-mesal spine-like modification on the posterior coxal fold and a branched palette of the telopodite) (compare Fig. 7 A–H with Attems 1936 : figs 59d, 77f, Carl 1941 : figs 139, 168–169, 178, 190, 194, 196–197, 214, 217, 220, 222, Demange 1961 : figs 322, 328–330; 1977a: figs 6, 8; 1989: figs 1, 3–4, 6 and Verhoeff 1936 : figs 2–4). Distribution. India , Sri Lanka ( Fig. 9 ). Species-groups. In total, there are 10 nominal Carlogonus species, including the new species described here. Based on a single character of the gonopod telopodite and not on phylogenetic evidences, nine species can be assigned into two species-groups. The species Carlogonus spinicaudus ( Gervais, 1847 ) is omitted due to the unavailability of relevant character details. Moreover, this species may be a junior synonym of Carlogonus subvalidus ( Carl, 1941 ) ( Mauriès et al. 2001 ) . The exaratus -group: Species-group with a single tibial spine on the gonopod telopodite. It includes five spe-cies— Carlogonus auriculus Demange, 1983 , Carlogonus exaratus ( Attems, 1936 ) , C. gayathri sp. nov. , C. robustior and C. subvalidus . The acifer -group: Species-group with paired tibial spines on the gonopod telopodite. It includes four species— Carlogonus acifer Demange, 1977 , Carlogonus chowdaiahi Demange, 1977 , Carlogonus palmatus Demange, 1977 and Carlogonus verhoeffi Demange, 1981 .