Thinophilus evenhuisi, 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 : 428-429

Thinophilus evenhuisi sp. nov.

(Figs. 15, 16)

Material examined. Holotype Male. SINGAPORE: Pulau Ubin , Chek Jawa, 12 September 2005, (reg. 25343, Si1040, LKCNHM).

Fig. 15. Thinophilus evenhuisi sp. nov., male. A, Antenna; B, Fore leg anteriorly; C, Mid femur; D, Hind femur.

Paratypes: SINGAPORE: 2 females with same provenance as holotype .

Etymology. This species is dedicated to Neal Evenhuis, with whom I started the study of the dolichopodid fauna in Singapore in 2000.

Diagnosis. A small species with 4 almost equally strong dc. Fore coxa yellow with short pale bristling anteriorly and at tip. All trochanters yellow. Fore femur with 2 very long, black bristles near middle (twice as long as femur is deep; sometimes a third brown or pale bristle towards base). Mid femur with a strong ventral bristle near middle. Hind femur with a row of long ventral bristles in basal half. Postpedicel dorsally and at tip brown, rest yellow. Apical tarsal segments of all legs brown. Epandrium about ¼ length of abdomen. Cerci yellowish white.

Male. Body length 2.29 mm; wing length 2.11 mm.

Head. Frons and face with shining dark metallic green ground colour. Face wide, at its narrowest point near middle, as wide as third antennal segment is long. Clypeus a little protruding. Palpus yellow with pale brown hairs. Postcranium slightly concave, shining dark metallic green. 2 long, diverging ocellars; 2 long (only slightly) shorter, converging verticals, pointing forward; no postocellars; 2 distinct postverticals. Postoculars black and uniseriate above (5–6), longer and white below.

Antenna (Fig. 15A) yellow, but first and second segment and third segment dorsally and with tip brownish black. Inner protuberance of second segment brown, outer one with lateral margin black; second segment with dorsal and slightly longer ventral bristles. Third segment about as long Mid leg. Coxa with a short, pale exterior bristle. Femur (Fig. 15C) swollen in basal half, near middle with 3 brown to black ventral bristles nearly as long as femur is wide. No anterior preapical. Tibia with an ad on basal quarter and a longer pd near middle; crown of short, apical bristles.

Hind leg. Coxa with a tiny, pale exterior bristle. Femur (Fig. 15B) ventrally straight, dorsally swollen in basal half. In basal half with 4 brown to black ventral bristles as long as femur is wide. No dorsal, no anterior preapical bristles; just a small preapical pv. Tibia with a tiny dorsal near middle and a stronger preapical dorsal bristle.

Wing clear. Veins brownish, hardly paler near base. Apical part of M 1+2 practically straight; tip of R 4+5 slightly converging with M 1+2. Wing boss present at about one Tp length from Tp. Apical part of M 3+4, 1.5 times as long as tp. Anal vein dark brown at its base, apical half not indicated. Haltere white. Squama white, with pale 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). Sternum 1 sclerotised. All sternites with fine, white hairs (longer than those on tergites). Surstyli and genital capsule (Fig. 16) brown; cerci yellowish white, dorsally not fused. Fig. 16. Thinophilus evenhuisi sp. nov. male. A, Epandrium ventrally; B, Epandrium and cercus laterally; C, Cerci dorsally.

as wide, apically rounded, truncate. Arista dorsal, 2.5–3 times as long as antenna, black, shortly pubescent; basal aristal segment short, black.

Thorax and scutellum shining dark metallic green; no dull black spots as far as can be seen in alcohol. No acr; 4 almost equally long dc (anterior shortest, posterior longest), preceded by a few tiny hairs. Scutellum with 2 marginals, without a minute lateral hairs at outer side. 1 upper and 2 lower, short (shorter than fore coxa is wide) pale propleural bristles.

Legs yellow with most hairs and bristles black. Fore coxa completely yellow, mid and hind coxae black. Legs with apical 3 tarsomeres completely darkened; tarsomere 5 almost black.

Fore leg. Coxa with short pale (yellowish) anteriorly and apically (not the usual long black bristles). Femur (Fig. 15B) swollen in basal third, apically slender with a row of ventral bristles: near middle with 2–3 long, black ventral bristles, about twice as long as femur is wide and one or two short, pale bristle near base. In apical third with a few, pale, brown av. A single, short brown preapical pv. Tibia without dorsal but a tiny pd on basal quarter; in basal 2/3 with an anteroventral row of tiny bristles, not as long as tibia is wide; ventrally without bristles. First tarsomere ventrally with only short bristling. Apical pair of bristles on tarsomeres very short (shorter than tarsomere is wide).

Female. Similar to male but lacking the long ventral bristles on the femora.

Remarks. This small species should be compared with T. minor sp. nov. The differences can be found in the key.

Distribution. Singapore.