Thinophilus, Wahlberg, 1844

Grootaert, Patrick, 2018, Revision of the genus Thinophilus Wahlberg (Diptera: Dolichopodidae) from Singapore and adjacent regions: A long term study with a prudent reconciliation of a genetic to a classic morphological approach, Raffles Bulletin of Zoology 66, pp. 413-473 : 468-469

Key to male Thinophilus of Singapore and adjacent regions

Note that the species from Borneo described by Parent (1935) are not mentioned in the present key because none of them occurs in Singapore or in the rest of the Malay Peninsula.

1. Fore legs with very long fine black ventral bristles on femur, (up to 3–4 times as long as femur is wide) and on fore tibia (Figs. 11, 20); if only very long white bristles on fore femur, go to T. parvulus Samoh et al., 2017 in couplet 21 ..............2

– If fore legs with long black ventral bristles, then at most twice as long as femur is wide.........................................................3

2. Legs yellow (posterior four coxae black); mid tibia without long bristles (Fig. 11) ( Singapore) .............. comatus sp. nov.

– Legs black or dark brown; fore and mid legs in male with longer and denser bristles, even on mid tibia (Fig. 20) ( Singapore) .. .................................... longicilia Evenhuis & Grootaert, 2002

3. Legs with fore coxae entirely black (often extreme tip yellowish or only basal half black as in T. yeoi sp. nov. Fig. 55).........4

– Legs with fore coxae completely yellow, but often a little darkened at extreme base.......................................……...…17

4. At least fore and mid femora black ......................................5

– All femora yellow to brownish...............................................8

5. Fore coxa completely black with black bristles.....................6

– Fore coxa with white bristles and fore femur with long white mixed with black bristles ( Thailand)........................................ ............................................. boonrotpongi Samoh et al., 2017

6. All femora black on basal two thirds, tip contrastingly yellow (Fig. 17). Hind trochanter brown; rest of legs yellow. Fore trochanter with a row of 6 long black ventral bristles with a curved tip (Figs. 17, 18D) ( Singapore) ................................... lenachanae sp. nov. – Fore and mid femora black, hind femur with a black stripe dorsally (Fig. 30). Fore trochanter without long black bristles......................................................................................7

7. Fore femur black on basal quarter only. Hind femur without strong posterior bristles in apical half ( Indonesia, Buru Island) ................................................ constrictus Parent, 1932

– Fore femur black on basal 2/3. Hind femur with a row of strong black, posterior bristles in apical half (Fig. 30) ( Thailand, Singapore)........................................... T. nigrilineatus sp. nov.

8. Fore coxa anteriorly not protruding........................................9

– Fore coxa with a large, protruding anterior hump (Fig. 27), densely set with black bristles; propleural bristles black; large species ( Singapore)....... murphyi Evenhuis & Grootaert, 2002

9. Hind tibia ventrally with a double row of very long soft hairs (Fig. 22); fore tibia with a very long, strong bent black dorsal bristle near base (Fig. 23C) ( Singapore)......... meieri sp. nov.

– Hind tibia ventrally without long soft hairs. Fore tibia without strong dorsal bristle at base ..................................................10

10. Tarsomere 2 of mid leg with a shield-like dorsal black protuberance (Fig. 37), tarsomere 3 white ...........................11

– Tarsomere 2 of mid leg simple without dorsal protuberance.. ...............................................................................................12

11. Mid femur at base with a cluster of distinct black ventral bristles. Hind femur with ventral bristles in apical half shorter than femur ( Thailand) ........... parmatoides Samoh et al., 2017

– Mid femur at base without a cluster of black ventral bristles (Fig. 37). Hind femur with ventral bristles in apical half longer than femur is wide ( Thailand, Singapore)................................ ..................................... parmatus Grootaert & Meuffels, 2001

12. All femora lacking a distinct bristling. Fore coxa completely black. Small species with small, yellow strap-shaped cerci, at most 1/5 length of venter ( Singapore)........... simplex sp. nov.

– Fore, mid or hind femora with at least some distinct bristles. ...............................................................................................13

13. Large species with very long slender legs (Fig. 52). Hind femur with a row of ventral bristles on basal ¾. Hind tibia with a very long thin dorsal preapical bristle that is nearly as long as tibia is long ( Thailand, Singapore) ............. superbus sp. nov.

– Small or large species with no such a slender legs; hind tibia without a very long preapical bristle....................................14

14. Large species (6 mm) with male terminalia half as long or more than abdomen is long ..................................................15

– Small species (2–3 mm) with male terminalia only about one third length of abdomen........................................................16

15. Tibiae and tarsi white. ( Malaysia, Thailand) ........................... ............................................. langkawensis Samoh et al., 2017

– Tibiae yellowish brown, apical 3 tarsomeres of all legs black. Fore coxa only black on basal half, apical half yellow (Fig. 56) ( Thailand, Singapore, Brunei) ....................... yeoi sp. nov.

16. Fore tarsomere 1 as long as following tarsomeres together. Mid femur at base with some short bristles and a row of long antero- and posteroventrals (Fig. 39A). (Peninsular Malaysia) ........... ......................................................... peninsularis Parent, 1935

– Fore tarsomere 1 shorter than following tarsomeres together. Only mid femur with a few long bristles at base (Fig. 40) much longer than femur is wide. Fore coxa black but paler posteriorly ( Singapore).................... puniamoorthyae sp. nov.

17. Wing with spot on middle of apical section of m 1+2 (level of wing boss), on cross vein and sometimes on vein R 4+5 (Fig. 42). If the clouding on the veins is weak: male with a bundle of long bristles on sternite 3 and 4 ( Thailand, Singapore)...... ................................... setiventris Grootaert & Meuffels, 2001

– Wing without spots and sternites lacking a bundle of long hairs on sternite 3 and 4, at most some short hairs.....................18