Carlogonus Demange, 1961

Sankaran, Pradeep M. & Sebastian, Pothalil A., 2020, A new species of Carlogonus Demange, 1961 from southern India (Spirostreptida Harpagophoridae, Harpagophorinae), with phylogenetic analysis and speciesgroup divisions in the genus, Zootaxa 4868 (1), pp. 27-40 : 28-29

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 .

Figures

FIGURE 2. Field photographs of Carlogonus gayathri sp. nov.. A: Male from Pullodu in Trippalur, Palakkad (MILLI- ADSH0012). B: Female from Pullodu in Trippalur, Palakkad (MILLI-ADSH0013). Photo courtesy Jimmy Paul.

FIGURE 7. Carlogonus gayathri sp. nov., male. A: Gonopods, ventral view. B: Same, dorsal view. C: Right gonopod after removing telopodite, dorsal view. D: Left gonopod, lateral view. E: Same, mesal view. F: Left telopodite, ventral view. G: Same, lateral view. H: Enlarged view of distal part of left telopodite, mesal view. I: Enlarged view of blepharochaetae, lateral view. Abbreviations: alpAC = antero-lateral process of anterior coxal fold, amhpAC = antero-mesal hook-like process of anterior coxal fold, amtAC = antero-mesal thumb-like process of anterior coxal fold, AC = anterior coxal fold, B = blepharochaetae, C = distal longitudinal crest, F = femur, FS = femoral spine, dtpP = distal thorne-like process of palette, P = palette, apPC = apical process of posterior coxal fold, blpPC = baso-lateral process of posterior coxal fold, imPC = internal mesal fold of posterior coxal fold, lpPC = lateral process of posterior coxal fold, mpPC = mesal process of posterior coxal fold, PC = posterior coxal fold, PX = paracoxite, ST = sternite, T = telopodite, TS = tibial spine, TT = tibiotarsus. Arrows indicate indentation on lateral margin of anterior coxal fold (1) and basal bifurcated seta on tibial spine (2). Scale bars: A–G = 1 mm; H–I = 0.5 mm.

FIGURE 9. Currently known distribution records of Carlogonus spp.. * Carlogonus acifer Demange, 1977, ♦ Carlogonus auriculus Demange, 1983, é Carlogonus chowdaiahi Demange, 1977, ■ Carlogonus exaratus (Attems, 1936), r Carlogonus gayathri sp. nov., ● Carlogonus palmatus Demange, 1977, □ Carlogonus robustior (Attems, 1936), ○ Carlogonus subvalidus (Carl, 1941), ▲ Carlogonus verhoeffi Demange, 1981 (record of Carlogonus spinicaudus (Gervais, 1847) and subsequent records of other species are omitted from the map due to the lack of locality details).