Cymatopus, Kertesz, 1901

Samoh, Abdulloh, Satasook, Chutamas & Grootaert, Patrick, 2018, New data on the marine genera Cymatopus Kertèsz and Thambemyia Oldroyd (Insecta, Diptera, Dolichopodidae) from rocky shores in southern Thailand with the description of a new species, Raffles Bulletin of Zoology 66, pp. 258-267 : 259

Key to male Cymatopus

and Thambemyia in Thailand

This key deals with marine dolichopodids from rocky shores with an apical arista on a triangular third antennal segment (postpedicel) and a pair of fronto-orbital bristles (bristle at each side of frons, halfway between base of antenna and vertex). For other marine dolichopodid genera, we refer to the key in Grootaert & Meuffels (2001).

1. Proboscis much shorter than eye height ( Fig. 1 ) ..................... ...........................................................................2 ( Cymatopus )

– Proboscis much longer than eye height ( Figs. 11 , 12 ) ............ ................................................. Thambemyia pagdeni Oldroyd

2. Hind legs modified, hind tibia and first tarsomere with long hairs ( Fig. 9 ) ............................................ C. longipilus Parent

– Hind legs simple without peculiar long hairs or bristles ( Fig. 1 ) ..............................................................................................3

3. Wing with hind border deeply indented and with fields of longer microtrichia on wing membrane ( Fig. 1 , arrow); large species (> 2.5 mm).................................. C. malayensis Parent

– Wing simple, hind border not deeply indented, at most a little folded ( Fig. 3 , arrow); smaller species (2–2.5 mm) ..............4

4. Male with vein R 2+3 simple; fore tibia with a black twisted foliaceous anterior bristle near middle and a long black apical bristle ( Fig. 6 )...................... C. thaicus Grootaert & Meuffels

– Male with vein R 2+3 near middle much thickened and undulating, costa also thickened ( Fig. 3 ); fore tibia without black anterior foliaceous bristle and without long apical bristle .................... ....................................................... C. mayakunae new species

Figures

Fig. 1. Cymatopus malayensis Parent habitus male: lb: leaf-like bristle on fore tibia; mt: fields of microtrichia on wing; t1: twisted fore tarsomere.

Fig. 11. Thambemyia pagdeni Oldroyd male habitus (photo credit = Maimon Husein).

Fig. 12.Thambemyia pagdeni Oldroyd female habitus (photo credit = Maimon Husein).

Fig. 9. Cymatopus longipilus Parent (Rayong prov.). Mid leg and swollen hind leg bearing long bristles. ht: hind tibia.

Fig. 3.Cymatopus mayakunae new species male habitus.cb: curved bristles on fore tibia; ht: hind tibia with dorsal row of bristles with swollen tip; arrow indicates fold in hind margin of wing set with long bristles.

Fig. 6. Cymatopus thaicus Grootaert & Meuffels habitus male. lb: leaf-like bristle on fore tibia; ht: hind tibia.