1  – P1Enp two-segmented………….…………….…………………………………….....(2)

– P1Enp three-segmented…………….……………………….…………..………..........(5)

2  – Exp-2 of P2–P4 without inner setae……….….………………………………...…........(3)

– Exp-2 of P2–P4 with one inner seta……….……….………………………..……….....(4)

3  – P5Exp and basesoendopod with five and three marginal setae/spines, respectively; caudal rami about 1.1 times as long as wide, with seta V transformed into swollen smooth element; …………………………………...……....................................... S. crassispinata [Madagascar]

– P5Exp and basesoendopod with six and four marginal setae/spines, respectively; caudal rami about 1.2 times as long as wide, with seta V normally developed…......................S. spinifer [Katchal Island (Nicobar Islands)]

4  – P5Exp with six marginal setae; caudal rami about 1.5 times as long as wide, with short spinule ornamentation on inner margin; setal formulae of Enp-1 and Exp-2 of P2–P4 as 1.0.1 and 0.0.1, respectively ................................ ....S. monardi [the area where is probably in Montenegro]

– P5Exp with five marginal setae; caudal rami about twice as long as wide, with long spinule ornamentation on inner margin; setal formulae of Enp-1 and Exp-2 of P2–P4 as 1.1.1 and 0.1.1, respectively; P1Enp-1 reaching mid of Exp-3; caudal seta IV setiform, well surpassing breaking plane of seta V………………………….....................S. brusinae [sensu Kunz (1974), France]

5  – P4 with two-segmented Enp; caudal rami about twice as long as wide, inner margin naked; caudal seta IV setiform and short, shorter than seta VI; P1Enp-1 reaching tip of Exp-2; setal formula of P2–P4 0.1.1………………………………………........... S.abei [Lake Biwa (Japan)]

– P4 with three-segmented Enp……………………………….……….……..……….…(6)

6  – P5Exp fused to baseoendopod, with five marginal setae; caudal rami with spinule ornamentation on inner margin; setal formulae of Exp-2 and Enp-1 of P2–P4 as 0.0.0…………... …………………………………………………......................... ....S. gangneungensis [Korea]

– P5Exp fused to baseoendopod, with six marginal setae………............................…..…..... (7)

– P5Exp free, with five marginal setae…………….……………………………...….…....(8)

– P5Exp free, with six marginal setae………………………………………….………...(11)

7  – Exp-2 of P2–P4 without inner setae………………………..... ..........S. daejinensis [Korea]

– Exp-2 of P2–P4 with inner setae ..........................................................S. yeonghaensis [Korea]

8  – Enp-1 of P2–P4 without inner setae; P1Enp-1 surpassing tip of Exp; caudal seta IV setiform, considerably surpassing breaking plane of seta V……….…………………….…….. …………………………………………...... ............S.consimilis [Lake Tanganyika (Africa)]

– Enp-1 of P2without inner seta, but Enp-1 of P3 and P4 with inner seta….........................(9)

9  – Caudal rami about 1.5 times as long as wide, with long spinule ornamentation on inner margin.……………………...... ...…...…............S. brusinae [sensu Fiers (1986), New Guinea]

– Caudal rami at least about 1.8 times as long as wide, with setular ornamentation on inner margin……………..……….…………………………..…………... ………………….. (10)

10  – Caudal seta IV spiniform and short, reaching or slightly surpassing breaking plane of seta V……................S. brusinae [sensu Petkovski (1954), Croatia; sensu Apostolov (1973), Bulgaria]

– Caudal seta IV setiform, considerably surpassing breaking plane of seta V……….…..... ………………………………………...……...………………….….....S. paktaii [Thailand]

11  – All P2, P3 and P4 without inner seta on Enp-1……....………...…….………..….......(12)

– Either P2 or P3 and P4 with inner seta on Enp-1…………....………………..…..........(14)

12  – Exp-2 of P2–P4 without inner seta………….. ..…....... S. vietnamica sp. nov. [Vietnam]

– Exp-2 of P2–P4 with inner seta……...…………..……..…..…………………...….....(13)

13  – Setal formula of Enp-3 of P2–P4 4.4.3………….............……………...……………… ………………S. neglecta [sensu Akatova (1935), Russia; sensu Por (1964), Israel; sensu Shen et al. (1979), China; sensu Chang (2009), Korea; and sensu Apostolov (1973), Bulgaria]

– Setal formula of Enp-3 of P2–P4 4.3.3…......S. neglecta [sensu Monchenko (1967), Romania]

14  – P2Enp-1 with inner seta; P1Enp-1 surpassing tip of Exp…………………………… ...……………………………...………………............ S. longirostris [New Guinea; Thailand]

– P2Enp-1 without inner seta, but P3 and P4 with inner seta on Enp-1…………………(15)

15  – Setal formula of Exp-3 of P2–P4 4.4.5; setal formula of Enp-3 of P2–P4 5.5.3…...…….. ………………………………………………………………….……......... S. indica [India]

– Setal formula of Exp-3 of P2–P4 4.4.4 or 4.3.4; setal formula of Enp-3 of P2–P4 3.4.3, 4.4.3 or 4.5.3…………………………………………………………………………...............(16)

16  – Exp-2 of P2 with inner seta, but Exp-2 of P3 and P4 without inner seta; setal formula of Enp-3 of P2–P4 4.5.3 ……………..…S.clandestina [sensu Arlt (1983), Baltic Sea (German)]

– Exp-2 of P2 and P3 without inner seta, but Exp-2 of P4 with inner seta…...…......…...... …………………………………………………………………………S. sindoensis [Korea]

– Exp-2 of P2–P4 with inner seta…………….…………….………………………......(17)

17  – Setal formula of Enp-3 of P2–P4 3.4.3.....S.clandestina [sensu Klie (1923), Germany]

– Setal formula of Enp-3 of P2–P4 4.4.3…………....…………….……………..……...(18)

18  – Caudal rami without setules on inner margin; P1Enp-1 reaching tip of Exp-2…...…… ……………………………..………………………............S. subterranea [Italy; Thailand]

– Caudal rami without setules on inner margin; P1Enp-1 reaching tip of Exp-3….........…(19)

– Caudal rami with setules on inner margin; P1Enp-1 reaching tip of Exp-2 at least but not surpassing tip of Exp-3……..……………..………………………………..........................(20)

– Caudal rami with hairs on inner margin; P1Enp-1 surpassing tip of Exp ...................….. (21)

19  – Caudal rami about 1.5 times as long as wide …S. tobaetobae [Sumatra, Java (Indonesia)]

– Caudal rami about 1.7–1.8 times as long as wide……..……………..………..…………. ……………………………………………………S. tobae wolterecki [Sulawesi (Malaysia)]

20  – Caudal rami about 1.5–2 times as long as wide……………….................S.clandestina [sensu Apostolov (1973), Bulgaria; sensu Chang (2009), Korea; sensu Shen et al. (1979), China]

– Caudal rami as long as wide……………….…......... S.clandestina brevicauda [Germany]

21  – P1Enp-3 about twice as long as wide.…….….……..............S. knabeni [America; Mexico]

– P1Enp-3 about three times as long as wide.....…….….………….….……….……….…… ….……….……….……………………………S. clandestina [sensu Noodt (1953), Germany]