Thinophilus, Wahlberg, 1844

Samoh, Abdulloh, Satasook, Chutamas & Grootaert, Patrick, 2017, Eight new species of marine dolichopodid flies of Thinophilus Wahlberg, 1844 (Diptera: Dolichopodidae) from peninsular Thailand, European Journal of Taxonomy 329, pp. 1-40 : 35-36

Key to male Thinophilus from the Thai-Malay Peninsula

1. Wing with dark spot on middle of apical section of M 1+2 (level of wing boss), on cross vein and sometimes on vein R 4+5, if the clouding on the veins is weak; male with a tuft of long bristles on sternite 3 and 4 ………………………………………… setiventris Grootaert & Meuffels, 2001

– Wing without spots and sternites with at most short hairs ……………………………………2

2. Fore femur with long ventral bristles, at least twice as long as femur is wide ………………3

– Fore femur with bristles that are at most a little longer than femur is wide …………………5

3. Fore femur in both male and female with 4–5 stiff brown bristles that are more than twice as long as femur is wide ( Figs 25 , 30 ). Legs yellow ………………………………………………4

– Fore and mid legs with very long, soft ventral bristles on femur, tibia and expanding on tarsomere 1. Legs darkened ( Singapore) ………………………………… longicilia Evenhuis & Grootaert, 2002

4. Fore coxa completely yellow. Fore femur strongly spindle-shaped dilated in basal quarter ( Fig. 25 ). Fore tibia longer than fore femur.Fore tarsomere1very long and slender,twice as long as fore tibia.Fore tarsomere 3 contrastingly yellowish white, tarsomeres 4 and 5 widened, black … spinatoides sp. nov.

– Fore coxa black. Fore femur weakly dilated at base. Fore tibia a little shorter than fore femur ( Fig. 30 ). Fore tarsomere 1 about as long as fore tibia. Fore tarsomere 3 not paler than preceding tarsomeres. Fore tarsomeres 4 and 5 not widened, black ………………………… spinatus sp. nov.

5. Fore coxa darkened on basal half or completely darkened ( variabilis sp. nov. usually has yellow fore coxa, but they might be brownish infuscate) …………………………………………………6

– Fore coxa completely yellow (except for extreme base) …………………………………………11

6. Tarsomere 2 of mid leg with a shield-like dorsal black protuberance ( Figs 16–17 ), tarsomere 3 white ………………………………………………………………………………………………7

– Tarsomere 2 of mid leg without dorsal protuberance …………………………………………………8

7. Mid femur at base with a cluster of distinct black ventral bristles ( Fig. 16 ). Hind femur with ventral bristles in apical half shorter than femur is wide ( Fig. 16 ) …… parmatoides sp. nov.

– Mid femur at base without a cluster of black ventral bristles ( Fig. 17 ). Hind femur with ventral bristles in apical half longer than femur is wide ( Fig. 17 ) ……………… parmatus Grootaert & Meuffels, 2001

8. All femora darkened, if femora yellow, fore femur with long white curly bristles at base. Tip of fore tibia and all tarsomeres 5 darkened at tip. Hypopygium short, less than one-third length of abdomen ( Fig. 1 ) ………………………………………………………… boonrotpongi sp. nov.

– All femora yellow, without long curly white bristles at base …………………………………9

9. Fore coxa entirely black. Large robust species with distinctly bristled legs ……………………10

– Fore coxa black on basal two-thirds. Small species (2 mm) with few bristles on legs …… …………………………………………………………………………… peninsularis Parent, 1935

10. Fore coxa in male protruding, hump-backed. Hypopygium less than half length of abdomen ……………………………………………………………… murphyi Evenhuis & Grootaert, 2002

– Legs entirely yellowish white except for all coxae darkened. Fore coxa not hump-backed swollen. Hypopygium elongate, more than half length of abdomen ( Fig. 6 ) … langkawensis sp. nov. 11. Very small species (less than 2 mm). Fore tibia with 2 strong brown posteroventral bristles near base ( Fig. 21 ) …………………………………………………………………………… parvulus sp. nov.

– Larger species. Fore tibia without strong brown posteroventral bristles near base …………12

12. Fore tibia with a ventral row of bristles longer than tibia is deep over entire length ( Fig. 36 ) … …………………………………………………………………………………… variabilis sp. nov.

– Fore tibia with only short ventral bristles …………………………………………………………13

13. Fore coxa anteriorly near base with long, soft white bristles and a single black bristle; apical bristles black. Fore femur in basal half with a row of 4–5 ventral bristles about as long as femur is wide (all trochanters yellow). Fore tarsomere 1 ventrally set with a row of black spinules; mid leg with apical tarsomeres 2 black (freshwater species) … nitens Grootaert & Meuffels, 2001

– Fore coxae without long soft bristles ……………………………………………………………14

14. Fore femur with only a single yellowish brown ventral bristle at base. Fore tarsomeres 1–4 whitish … ……………………………………………………………… asiobates Evenhuis & Grootaert, 2002

– Fore femur with only short ventral bristles, without the single basal bristle. All apical tarsomeres yellowish …………………………………………………………………………… minutus sp. nov

Figures

Fig. 25. Thinophilus spinatoides sp. nov., ♂, habitus.

Fig. 30. Thinophilus spinatus sp. nov., ♂, habitus.

Fig. 16. Thinophilus parmatoides sp. nov., ♂, habitus.

Fig. 17. Thinophilus parmatus Grootaert & Meuffels, 2001, ♂, habitus.

Figs 1–2. Thinophilus boonrotpongi sp. nov. 1. ♂, habitus. 2. ♀, habitus.

Fig. 6. Thinophilus langkawensis sp. nov., ♂, habitus.

Fig. 21. Thinophilus parvulus sp. nov., ♂, habitus.

Fig. 36. Thinophilus variabilis sp. nov., ♂, habitus.