Nilothauma Kieffer, 1921

Niitsuma, Hiromi, 2016, Two species of Nilothauma Kieffer (Diptera, Chironomidae) from Japan, with description of a new species, Zootaxa 4079 (5), pp. 573-581 : 579-580

Key to male imagines of the genus Nilothauma Kieffer

[Neotropical species not included]

1. Tergite IX with one dorsal projection...................................................................... 2

- Tergite IX with 2 dorsal projections...................................................................... 7

2. Dorsal projection weakly developed, situated posteriorly on tergite IX, close to base of anal point; Palaearctic Japan, Oriental China, Thailand............................................................... N. japonicum Niitsuma, 1985

- Dorsal projection well developed, situated anteriorly on tergite IX, distant from base of anal point.................... 3

3. Superior volsella very slender, without microtrichia, with 2–3 spine-like setae..................................... 4

- Superior volsella at least as thick as inferior volsella, extensively covered with microtrichia, with 3–5 long and some short setae............................................................................................... 5

4. Dorsal T IX projection bell-shaped, with setae thickened at apices; anal point broad; superior volsella with 2 spine-like setae; Ghana................................................................... N. duminola Adam & Saether, 1999

- Dorsal T IX projection long, without setae, and 3-pronged at apex; anal point narrow; superior volsella with 3 spine-like setae; Ghana.................................................................... N. fuscina Adam & Saether, 1999

5. Anal point tapering or slightly widened medially but not spatulate; median volsella digitiform, at least twice as long as wide with 3 or occasionally 2 apical setae; Canada, USA...................................... N. babiyi (Rempel, 1937)

- Anal point spatulate; median volsella consisting of 2 setae on separate or fused tubercles............................ 6

6. Dorsal T IX projection small, with setae at apex only; Canada...................... N. verrucum Adam & Saether, 1999

- Dorsal T IX projection extending over most of tergite IX; Australia................. N. adunatum Adam & Saether, 1999

7. Wing with dark areas or bands; anterior T IX projection long and deeply divided...................................8

- Wing without dark markings; anterior T IX projection variably developed...................................... 16

8. Anterior T IX projection with setae not concentrated around apex............................................... 9

- Anterior T IX projection with apical setae only............................................................. 10

9. Eye hairy, at least among marginal ommatidia; wing with 5 dark spots; anal point present; South Africa........................................................................................... N. harrisoni Adam & Saether, 1999

- Eye bare, wing with 2 dark bands; anal point absent; Ghana......................... N. insolitum Adam & Saether, 1999

10. Posterior T IX projection deeply divided into antero-dorsal and postero-ventral parts.............................. 11

- Posterior T IX projection not as above................................................................... 13

11. Anterior T IX projection with apical setae simple, separate; anterior part of posterior projection apically pointed; postero- median wing spot extends on both sides of Cu1; Sudan, Chad, Guinea, Ivory Coast, Nigeria, Senegal, Togo.............................................................................................. N. pictipenne Kieffer, 1921

- Anterior T IX projection with setae forming fan-like structures; anterior part of posterior projection with blunt apex; postero- median wing spot exclusively proximal of Cu1.............................................................. 12

12. Wing with 4 dark areas; setae of anterior T IX projection branched at tip; Ghana...... N. flabellatum Adam & Saether, 1999

- Wing with 3 dark areas; apical setae of anterior T IX projection not branched, lamellar; Ghana................................................................................................ N. kakumense Adam & Saether, 1999

13. Posterior T IX projection either with a disto-dorsal lobe or subapical constriction................................ 14

- Posterior T IX projection without a distal lobe or construction................................................ 15

14. Posterior T IX projection with long antero-lateral arms and a disto-dorsal lobe; Tanzania..................................................................................................... N. anderseni Adam & Saether, 1999

- Posterior T IX projection without antero-lateral arms, with subapical constriction and apical setae; Zimbabwe.................................................................................. N. latocaudatum Adam & Saether, 1999

15. Posterior T IX projection without microtrichia except on long antero-lateral arms; superior volsella without antero-median extension; median volsella present; Palaearctic Japan, Oriental China.................... N. nojirimaculatum Sasa, 1991

- Posterior T IX projection without antero-lateral arms, covered with microtrichia; superior volsella with an antero-median extension; median volsella apparently absent; Palaearctic Japan......................... N. hibaraquartum Sasa, 1993

16. Apical setae of anterior T IX projection plumose............................................................ 17

- Apical setae of anterior T IX projection not plumose....................................................... 23

17. Anal point with microtrichia along median ridge and apical margin; Oriental China.. N. pandum Qi, Lin, Wang & Shao, 2014

- Anal point without microtrichia......................................................................... 18

18. Superior volsella pad-like, with microtrichia extensively; Palaearctic Japan.................. N. hibaratertium Sasa, 1993

- Superior volsella slender, microtrichia absent or limited within small area when present............................ 19

19. Superior volsella without lateral spur; Thailand................................... N. mergae Adam & Saether, 1999

- Superior volsella with lateral spur........................................................................ 20

20. Superior volsella without setal brush or fringe; Oriental China........................... N. acre Adam & Saether, 1999

- Superior volsella with apical setal brush or fringe.......................................................... 21

21. Superior volsella 4–5 times as long as median volsella; Palaearctic Japan.......................... N. niidaensis n. sp.

- Superior volsella 2–3 times as long as median volsella....................................................... 22

22. Anterior T IX projection 2–4 times as long as broad; Canada, USA......................... N. bicorne ( Townes, 1945)

- Anterior T IX projection broader than long; USA...................................... N. mirabile ( Townes, 1945)

23. Superior volsella pad-like, with microtrichia extensively..................................................... 24

- Superior volsella slender, microtrichia absent or limited within small area when present............................ 25

24. Superior volsella tapering, widest near base; Europe................................... N. brayi (Goetghebuer, 1921)

- Superior volsella narrowest at base, widest about 1/3 from apex; Australia............. N. infissum Adam & Saether, 1999

25. Anal point trifid; anterior T IX projection very long, tapering to parallel-sided apex, with setae only apically; posterior projec- tion distally very slender, with apical setae; Ghana, D. R. Congo................... N. burmeisteri Adam & Saether, 1999

- Anal point simple; anterior T IX projection wart-like, with setae not concentrated around apex; posterior projection triangular or bell-shaped....................................................................................... 26

26. Anal point parallel-sided; anterior T IX projection with setae thickened at apices; Ghana...................................................................................................... N. ankasense Adam & Saether, 1999

- Anal point spatulate; anterior T IX projection with setae not thickened at apices; Oriental China.......................................................................................... N. quatuorlobum Yan, Tang & Wang, 2005