Rheotanytarsus

Key to males of Rheotanytarsus of China

1. Antenna with 12 flagellomeres .................................................................................... 2

­ Antenna with 13 flagellomeres .................................................................................... 3

2. Apical lamellae of median volsella bulbous (Fig. 5) ............................. R. bullus sp. n.

­ Apical lamellae of median volsella not bulbous (Fig. 7) ............... R. polychaetus sp. n.

3. Apex of anal point pointed; tergite IX bare (Fig. 13) ........................... R. apiculus sp. n.

­ Apex of anal point spatulate, as wide as its basal width, or at least rounded................ 4

4. Abdomen banded. Posterior margin of tergite IX lateral to anal point straight (Fig. 9). ................................................................................................................... R. liuae sp. n.

­ Abdomen evenly coloured. Posterior margin of tergite IX forming a triangular base for the anal point ................................................................................................................ 5

5. Median volsella long, reaching beyond apex of inferior volsella (Kyerematen & Saether 2000: Figs. 43–46) ................................ R. buculicaudus Kyerematen & Saether

­ Median volsella short, not reaching beyond apex of inferior volsella ......................... 6

6. Base of anal point with a tuft of setae (Fig. 15) ..................................... R. fundus sp. n.

­ Base of anal point without setal cluster ........................................................................ 7

7. Gonostylus tapering gradually to rounded apex ........................................................... 8

­ Gonostylus abruptly tapered in apical portion and with narrow apex ........................ 10

8. Superior volsella subtriangular (Fig. 18)....................................... R. brevipalpus sp. n.

­ Superior volsella oblong .............................................................................................. 9

9. Lamellae of median volsella fused into plate, anal point without anal crests (Sasa 1980: Fig. 11; Wang & Zheng 1993: Figs. 1–2; Kyerematen, Andersen & Saether 2000: Figs. 3 A–D) .......................................................................... R. tamaquartus Sasa

­ Lamellae of median volsella not fused into plate, anal point with well developed crests (Tokunaga 1938: Fig. 31; Chaudhuri et al 1994: Figs. 2–3; Kyerematen, Andersen & Saether 2000: Figs. 1 A–D; Sasa & Kikuchi 1986: Fig. 3 J; Wang & Zheng 1993: Fig. 4) ................................................................................................. R. aestuarius (Tokunaga)

10. Gonostylus recurved at apex ...................................................................................... 11

­ Gonostylus not recurved at apex ................................................................................ 12

11. Superior volsella with bluntly rounded apical projection (Johannsen 1932: Fig. 37; Chaudhuri, Datta & Mazumdar 1994: Fig. 1; Kyerematen, Andersen & Saether 2000: Figs. 2 D–G; Wang & Zheng 1993: Figs. 5–6) .......................... R. acerbus (Johannsen)

­ Superior volsella rounded (Fig. 2) ......................................................... R. aphelus sp. n.

12. Superior volsella rectangular. Median volsella with almost all lamellae fused into plate (Fig. 11) .................................................................................... R. quadratus sp. n.

­ Superior volsella subtriangular or bean­shaped. Median volsella with apical foliate

setae fused into plate and markedly recurved with sickle­shaped apex ..................... 13 13. Superior volsella with posterior margin produced giving a hook­like projection (Lehman 1970: Figs. 11–13; Albu 1980: Fig. 191; Wang and Zheng 1993: Fig. 3) .............. .............................................................................................. R. muscicola Thienemann ­ Superior volsella rectangular and with rounded margin ............................................ 14

14. Anal point spatulate (Sasa 1980: Fig. 8) .......................................... R. tamatertius Sasa

­ Anal point narrow at apex (Tokunaga 1938: Fig. 29; Lehmann 1970: Figs. 9–10) ....... ................................................................................................... R. pentapodus (Kieffer)