Thinophilus comatus, Grootaert, 2018

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 : 425-428

Thinophilus comatus sp. nov.

(Figs. 11–14)

Material examined. Holotype male, SINGAPORE: Pulau Ubin , Chek Jawa, mangrove 2 October 2003 (reg. 23097, leg. PG, Malaise trap).

Paratypes: 1 male, Pulau Ubin, PU1 , mangrove, 12 May 2012 (reg. 29228, Ma0559, Mal.) ; 1 female, PU2 , mangrove, 20 April 2012 (reg. 29189, Ma0620, Mal.) ; 1 female, PU3 , mangrove, 20 May 2012 (reg. 29243, Ma0737, Mal.) ; 1 male, PU4 , mangrove, 17 May 2013 (reg. 29928, Ma4954, Mal.) .

More paratypes are cited in Annex 1. All specimens were recorded from Semakau.

Etymology. The name refers to the hairiness of the fore legs.

Diagnosis. A medium-sized species with yellow palpus; antenna dorsally and apically brown, ventrally yellow. Third antennal segment shorter than high, with a rounded tip. Legs yellow, fore coxa with brown streak at extreme base, posterior four coxae black. Fore femur with a double row of very long, fine ventral bristles. Fore tibia, tarsomeres 1–4 also with long ventral bristles. Mid femur with 4 very long bristles in basal two thirds; mid tibia lacking long ventral bristles. 5 dc (almost equally long, but becoming longer towards the rear). No dull spots on mesonotum; wing brownish. Sternites with short black bristles.

Male. (Fig. 11). Body length 3.1 mm; wing length 2.5 mm.

Fig. 11. Thinophilus comatus sp. nov. male habitus.

Head. Frons and face with shining dark metallic green ground colour. Face, narrower than depth of third antennal segment. Clypeus protruding, about 1/2 length of epistoma. Palpus yellow, with black bristly hairs. Rostrum large (half-length of height of eye) dark brown with white hairs. Postcranium shining dark metallic green, concave. 2 long, diverging black ocellars; 2 long (only slightly) shorter, converging verticals, pointing forward; minute postocellars; 2 distinct postverticals, longer than upper postoculars. Postoculars in upper third black and uniseriate; below white and longer; near mouth with a few additional white bristles.

Antenna largely yellow, but dorsally and tip brownish. Second segment with lateral margin black; with some dorsal and ventral

Fig. 12. Thinophilus comatus sp. nov. male. A, Antenna; B, Anterior view fore leg; C, Mid femur.

bristles. Third segment a little higher than long; tip with a rounded apex (Fig. 12A). Arista subapical, 2 times as long as antenna, black, faintly pubescent; basal aristal segment short.

Thorax and scutellum shining dark metallic green; no dull black spots. No acr; 5 long dc, almost equally long, anterior shortest, prescutellar longest. Scutellum with 2 marginals, with a fine lateral hair at each side. 3 upper and 3 lower white propleural bristles.

Legs yellow with black hairs and bristles, fore coxa yellow with a black streak at extreme base, four posterior coxae black. Posterior four trochanters yellowish not brown. Apical tarsomere of all tarsi brown.

Fore leg (Fig. 12B). Coxa with numerous long bristles anteriorly, those exteriorly the longest. Fore femur only slightly swollen in basal half, set with a double row very long ventral bristles (the bristles in the posterior row at least four times as long as femur is wide); Tibia, four basal tarsomeres also with a double row of long, fine ventrals (those in the posterior row, or posteroventral row the longest). Tibia with a short dorsal bristle near base and a longer beyond middle.

Mid leg. Coxa with a long black exterior. Femur thickened on basal half; ventrally in basal two thirds with about 5 long, fine bristles (Figs. 11, 12C); anteroventrally with a row of short bristles. Tibia with 2 pd and 1 pv near middle, no long ventral bristles present.

Hind leg. Coxa with a short black exterior. Femur thickened on basal half; withour ventral bristles; on apical third a long anterodorsal. Tibia with 2 ad, 2 pd and a crown of long apicals.

Wing feebly brownish tinged, without darker shades (Fig. 11). Veins yellowish brown. Apical part of M 1+2 curved up near middle, from there on running parallel with R 4+5. Apical part Fig. 13. Thinophilus comatus sp. nov. male genitalia. A, Ventral view epandrium; B, Lateral view epandrium; C, Dorsal view cercus; D, Lateral view hypandrium with phallus.

of M 3+4 as long as tp. Anal vein dark brown on basal half. Halteres white. Squamae white, with numerous white cilia.

Abdomen with a shining metallic green ground-colour. Tergites covered with short black bristles and somewhat longer marginals (those at side of first tergum longest). Sternites with short black bristles. Genital capsule, surstyli and cerci brownish with white hairs. Surstylus furcate at apex (Fig. 13B). Cerci dorsally fused (Fig. 13C).

Female. In most respects identical to male but no long bristles on the fore and mid legs. Legs generally darker in female.

Remarks. The long bristles on the fore femora, tibiae and basal tarsi of Thinophilus comatus are striking. In contrast to the similar T. longicilia Evenhuis & Grootaert that has dark brown legs, T. comatus sp. nov. has yellow legs in males. However the legs are sometimes quite brownish in the female so that females are difficult to recognise from T. longicilia . T. comatus sp. nov. lacks long ventral bristles on the mid tibia in contrast to T. longicilia that has long ventrals on the mid tibia.

T. comatus sp. nov. was accidentally mentioned as T. cometes in Evenhuis & Grootaert (2002) as a manuscript name and thus the name became a nomen nudum.

Fig. 14. Thinophilus comatus sp. nov.: Phenology during a 2-year survey (MIP).

Bionomics. Thinophilus comatus sp. nov. is active in the front as well as in the back mangrove.

Phenology. Thinophilus comatus sp. nov. has its peak activity in May followed by a very low activity from June to December. There is no clear relationship of its activity with the monsoons.

Distribution. Singapore.

Although that T. comatus sp. nov. is abundant on Pulau Semakau and Pulau Ubin, it was not recorded in other localities in Singapore.

A similar and common species occurs in Brunei that has only the fore leg with very long bristles on the femur, tibia and basal tarsomeres. The fore coxa is black except for the tip. In T. comatus sp. nov., the fore coxa is yellow in the male except for the extreme base; all tarsomeres 5 are black while brown in T. comatus sp. nov. and there are no long ventral bristles on mid femur (about 5 long ventral near base in T. comatus sp. nov.). This species is probably T. ciliatus Parent, 1935 (p. 525) described from N. Borneo (it has black fore coxa, squama with rigid black ciliation).