Review of the millipede tribe Polydrepanini, with the description of a new species from Kerala state, southern India (Diplopoda, Polydesmida, Paradoxosomatidae, Alogolykinae)

Abstract

The tribe Polydrepanini is rediagnosed through an elongate, mostly slender, sometimes twisted/helicoid gonofemorite and a more or less thin, mostly flagelliform, suberect, apical or subapical solenomere often forming a conspicuous loop/curve near the base. The tribe presently encompasses seven genera, all redefined, illustrated and keyed: Dasypharkis Attems, 1936, stat. revalid., Delarthrum Attems, 1936, Grammorhabdus Carl, 1932, stat. revalid., Pocockina Jeekel, 1965, Polydrepanum Carl, 1932 (= Gyrodrepanum Carl, 1932 and Hindomorpha Golovatch, 1984, both syn. nov.), Telodrepanum Carl, 1932, and Xiphidiogonus Carl, 1932. The genus Polydrepanum is shown to currently comprise only four described species, all also redefined, depicted and keyed: Polydrepanum tamilum Carl, 1932 (the type species), P. horridum Golovatch, 1984, P. granuliferum (Attems, 1936), comb. nov. ex Hindomorpha, and P. lamprum (Chamberlin, 1920), comb. nov. ex Gyrodrepanum. Grammorhabdus fissus (Sankaran & Sebastian, 2018) is formally transferred from Polydrepanum, comb. nov. Because Polydrepanum implicatum Carl, 1941 shows a strongly shortened gonopodal femorite, coupled with a distal and flagelliform solenomere, this species is considered as not only somewhat intermediate between the tribes Alogolykini and Polydrepanini as redefined here, but it is formally assigned to Alogolykini as the type species of Carlogonopus gen. nov. (masculine), with C. implicatus (Carl, 1941), comb. nov. ex Polydrepanum, as well as a comb. nov. ex Telodrepanum. A somewhat similar situation concerns Manikidesmus suriensis Bhakat, 2021, a still invalid genus and species from West Bengal, eastern India that likewise shows a clearly shortened gonofemorite. However, this being even more important, Manikidesmus suriensis is a “nomen nudum” not available yet for zoological nomenclature. The large and mainly Himalayan genus Delarthrum is briefly reassessed, mainly in connection with a new species, D. anomalans sp. nov., described from Kerala, southern India and placed in a species-group of its own. Some general considerations concerning the diversity and distribution of the subfamily Alogolykinae are presented.