Otostigmus niasensis Silvestri, 1895

Otostigma niasense Silvestri, 1895, 715. Nias Island, Sumatra. Otostigmus niasensis: Kraepelin, 1903, 118.

O. (O.) niasensis: Attems, 1930, 140.

Description. Type material not examined. (Silvestri’s data augmented from Kraepelin (1903), who re-examined the type material. Kraepelin’s data in parentheses). Length 38 (42) mm. 17–22 (16–19) antennal articles (the basal 2.33 glabrous). 3+3 forcipular coxosternal teeth. Tergites without keels but with spinules (laterally with spinules from 12 and rugulose), with paramedian sutures from 4, (6) marginate from 6 (7). Sternites with very short anterior paramedian sutures with median and posterior depressions (without clear depressions). Sternite of ultimate legbearing segment trapezoidal (attenuated). Coxopleural process with three apical spines. Legs 1–20 with a tarsal spur (two tarsal spurs on legs 1–4 or 5, the rest to 20 with one). Ultimate leg prefemoral spines 4, 3, 1, 1 + 5, 1, 2, 2. (VL 4, VM 2, M 1, DM 1, CS 1).

Remarks. Presumably the specimen with 17 antennal articles was a juvenile and the antenna with 16 articles was damaged. O. niasensis is very similar to O metallicus and O. sucki, being differentiated by the coxopleural process with three apical spines only and ultimate leg lacking a tarsal spine, two not totally reliable characters. Like O. sucki it may well be a junior synonym of O. metallicus but it is here retained pending reassessment as more material becomes available.