Key to the valid species of the Otostigmus rugulosus group (Modified from Lewis, 2010) 1 With prefemoral distodorsal spine on leg 20................................................................. 2 - Without prefemoral distodorsal spine on leg 20.............................................................. 3 2 Typically with 4+4 main forcipular coxosternal teeth, tergites without spinules, sternite 21 with sides converging posteriorly.. O. spinosus - Typically with 3+3 main forcipular coxosternal teeth, tergites typically with spinules, sternite 21 with sides ± parallel............................................................................................... O. punctiventer 3 With 3+3 main forcipular coxosternal teeth................................................................. 4 - With 4+4 main forcipular coxosternal teeth................................................................. 5 4 With a single apical coxopleural spine............................................................. O. martensi - With two or three apical coxopleural spines................................................................. 6 5 Coxopleural process long, and curved in females, ultimate leg prefemora with four rows of spines, leg 20 with one tarsal spur................................................................................... .. O. xizangensis n. sp. - Coxopleural process short and straight, ultimate leg prefemora with three rows of spines, leg 20 without tarsal spur.......................................................................... O. rugulosus incl. O. rugulosus striaturatus 6 Sternite paramedian sutures absent or present on anterior sternites only and very short ............................... 7 - Sternite paramedian sutures present...................................................................... 10 7 Tergites with small tubercles................................................................... O. noduliger - Tergites without small tubercles.......................................................................... 8 8 Coxopleural process without lateral spines........................................................ O. olivaceus - Coxopleural process with one or two lateral spines........................................................... 9 9 First 3 pairs of legs with two tarsal spurs, ultimate legs without tarsal spur................................... O. feae - First 15 pairs of legs with two tarsal spurs, ultimate legs with tarsal spur................................. O. fossuliger 10 With (19)20–21 antennomeres and two apical and one subapical coxopleural spine................................ 11 - With 18 antennomeres and two apical coxopleural spines................................................ O. beroni 11 Sternite paramedian sutures complete in mid-body region, the basal 2.66 antennomeres glabrous. Sternite 21 narrowed posteriorly........................................................................ O. angusticeps schindleri - Paramedian sutures occupying at most anterior 50% of each sternite in mid-body region, the basal 2.33 antennomeres glabrous. Sternite 21 with sides diverging, parallel or converging posteriorly........................................ O. astenus

Published as part of Niu, Meilian, Li, Yixuan & Di, Zhiyong, 2021, Otostigmus (Otostigmus) xizangensis n. sp., from China and a case of sexual dimorphism in the subgenus Otostigmus (Otostigmus) Porat, 1876 (Chilopoda, Scolopendromorpha, Scolopendridae), pp. 295-300 in Zootaxa 5081 (2) on page 300, DOI: 10.11646/zootaxa.5081.2.8, http://zenodo.org/record/5771838