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

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.

Impact of bottom trawling on sediment characteristics--a study along inshore waters off Veraval coast, India

The present communication is a study on the impact of bottom trawling on the sediment characteristics along Veraval coast, which is the largest trawler port of India. Experimental bottom trawling was conducted from MFV Sagarkripa at five transects of water depths 15-20 m, 21-25 m, 26-30 m, 31-35 m and 36-40 m in commercial trawling grounds. Trawling was conducted for 12 months in a span of 15 months (September 2005-November 2006) excluding the trawl ban period (June to August). The sediment texture was analysed by pipette analysis and organic matter by wet oxidation method. The variations in organic matter and sediment texture were prominent between the stations selected at different depths. The sedimentary organic matter exhibited variations with different water depths and seasons. The organic matter content decreased with depth. Experimental trawling considerably reduced the organic matter content at all depths. Continued and incessant trawling operation can cause even more drastic reductions, where organic matter (OM) content is already very small. The sand proportion showed depth-wise variation; but seasonal and trawling effect was not significant showing highest values at 36-40 m depth. The silt proportion did not exhibit significant depth-wise variation. The seasonal variation of silt was significant whereas trawling effect imparted to silt was not evident. Trawling has no significant effect on clay concentration. But seasonal variation had great influence on the clay distribution and indicated significantly high depth-season interaction. The sediment of the study area was predominant in silt proportion. It was observed that the seasonal/natural variations were more prominent masking the trawling effect on silt.