Thinophilus nigrilineatus, 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 : 443-447

Thinophilus nigrilineatus sp. nov.

(Figs. 30–32)

Material examined. Holotype Male. SINGAPORE, Semakau , SMN1, 25 April 2013 (reg. 29890; Ma4038; ZRC LKCNHM) . Paratypes: SINGAPORE: 1 female, SMN1 , mangrove, 27 February 2014 (reg. 30453, Ma8238, Mal.) ; 1 female, SMN2 , mangrove, 8 November 2012 (reg. 29561, Ma2658, Mal.) ; 2 females, MN2 , mangrove, 15 November 2012 (reg. 29574, Ma2681, Mal.) ; 1 female, SMN2 , mangrove, 22 November 2012 (reg. 29587, Ma2668, Mal.) ; 1 male, SMN2 , mangrove, 10 January 2013 (reg. 29678, Ma2363, Mal.) ; 2 males, SMN2 , mangrove, 17 January 2013 (reg. 29691, Ma2378, Mal.) ; 1 female, SMN2 , mangrove, 14 February 2013 (reg. 29743, Ma3493, Mal.) ; 1 male, SMN2 , mangrove, 28 February 2013 (reg. 29769, Ma3499, Mal.) ; 1 male, SMN2 , mangrove, 14 March 2013 (reg. 29797, Ma3570, Mal.) ; 1 male, 2 females, SMN2 , mangrove, 11 April 2013 (reg. 29856, Ma4288, Mal.) ; 1 male, SMN2 , mangrove, 18 April 2013 (reg. 29867, Ma4305, Mal.) ; 1 female, SMN2 , mangrove, 1 August 2013 (reg. 30067, Ma5165, Mal.) ; 1 female, SMN2 , mangrove, 14 November 2013 (reg. 30259, Ma6335, Mal.) ; 1 male, 1 female, SMN2 , mangrove, 3 January 2014 (reg. 30350, Ma7735, Mal.) ; 1 male, 1 female, SMN2 , mangrove, 7 February 2014 (reg. 30415, Ma8286, Mal.) ; 1 male, 1 female, SMN2 , mangrove, 6 March 2014 (reg. 30462, Ma8332, Mal.) ; 1 female, SMN2 , mangrove, 27 March 2014 (reg. 30506, Ma8350, Mal.) ; 1 male, SMN3 , mangrove, 12 April 2012 (reg. 29168, Ma0183, Mal.) ; 1 female, SMN3 , mangrove, 31 January 2013 (reg. 29718, Ma2401, Mal.) ; 1 female, SMN3 , mangrove, 3 January 2014 (reg. 30351, Ma7806, Mal.) ; 1 male, SMN3 , mangrove, 16 January 2014 (reg. 30377, Ma8370, Mal.) ; 2 females, SMN3 , mangrove, 29 January 2014 (reg. 30403, Ma7822, Mal.) ; 1 male, 1 female, SMN3 , mangrove, 7 February 2014 (reg. 30411, Ma8381, Mal.) ; 1 male, SMN3 , mangrove, 13 February 2014 (reg. 30429, Ma8386, Mal.) .

Etymology. The name refers to the black dorsal stripe on the hind femur that is typical for that species.

Diagnosis. Robust species with brown antenna; scape almost as long as postpedicel; the latter not rounded, but truncate; base of arista brown, apical 2/3 white. Long ocellars but short verticals. All coxae black. Fore coxa anteriorly not produced like in T. murphyi , with minute white hairs only. Fore and mid femur black, only apex yellow. Hind femur with a black dorsal stripe and ventrally yellow. All femora and tibiae with distinct ventral bristles that are at least as long as femur or tibia is wide. Hind femur curved on basal half, apical half with 5 strong black spine-like bristles. Cerci white with long white bristles.

Male. (Fig. 30) Body length 6 mm; wing length 5 mm.

Head. Frons and face with a dark metallic green ground-colour with blue reflections. Frons sunken between the eyes. Face above middle, as wide as depth of postpedicel. Palpus yellow with about 10 black bristly hairs. Rostrum large, dark brown with white hairs. 2 long diverging ocellars; 2 short Fig. 31. Thinophilus nigrilineatus sp. nov., male terminalia. A, Epandrium ventrally; B, Epandrium laterally; C, Cerci dorsally.

Fig. 32. Thinophilus nigrilineatus sp. nov.: Phenology during a 2-year survey (MIP).

verticals half as long as ocellars, pointing forward; 2 distinct postverticals. Postoculars black, uniseriate above, the favoris below composed dense whitish long hairs.

Antenna brown. Scape almost as long as postpedicel. Postpedicel not rounded, but truncate; its tip produced dorsally hence arista rather dorsal. Arista about twice as long as all antennal segments together, base brown, apical 2/3 white.

Thorax and scutellum shining dark metallic green, with blue reflections when seen from behind; no dull black spots. No acr; 6 dc with anterior 5 rather short and equally long, prescutellar one twice as long as preceding. Scutellum with 2 long marginals, with a short lateral hair at outer side. Propleural bristles white, 6 upper and 6 much longer bristles below.

Legs yellow with black markings and black hairs and bristles. All coxae black, fore femur with basal 2/3 black, mid femur almost entirely black with only apical fifth yellow, hind femur above on apical 2/3 with a black dorsal stripe, continuing in a black ring on apical fifth; hind tibia with base also darkened. All tarsomeres with tips annulated black; apical tarsomere entirely black.

Fore leg. Coxa anteriorly with minute white hairs bristles; only apical bristles black. Trochanter with short black hairs. Femur a little thickened in basal 2/3; ventrally with a double row of long black bristles a little longer as femur is wide on basal half; while on apical half even twice as long. Fore tibia also with a double row of long black bristle being 1.5 times as long as tibia is wide. Fore tarsomere 1 with a long of long posterior bristles, ventrally bare (not the usual spinules). Tarsomeres 2, 3, and 4 anteriorly and posteriorly with a long subapical bristle (the bristles are much longer than tarsomere is wide.

Mid leg. Coxa with a short black exterior bristle. Trochanter with short black hairs.

Femur ventrally with a double row of black bristles, as long as femur is wide. An anterior and posterior short spine-like preapical bristle (variable number).

Tibia ventrally with a row of fine bristles being twice as long as tibia is wide; anteroventrally also with a row of long hairs.

Hind leg. Coxa without exterior bristle. Trochanters with a row of long black bristles. Femur dorsoventrally curved in basal half. Two dorsal bristles, a preapical dorsal, preapical anterior, 6 strong posterior spine-like bristles in apical half. Ventrally densely set with fine bristles, in apical half as long as femur is wide. Tibia with 3 strong anterior bristles in basal half; ventrally with a double row of long fine hair-like bristles, near middle nearly twice as long as tibia is wide. Tarsomeres with a long fine preapical bristle.

Wing clear, without darker shades (Fig. 30). Veins brown, paler near base; costa black. Apical part of M 1+2 undulating; Apical part of M 3+4 as long as tp. Anal vein dark brown at its base, indicated for basal third only. Haltere white, with a patch of small black hairs dorsally at base Squama white, with short white cilia.

Abdomen with a shining metallic green ground-colour. Tergites covered with short black bristles and somewhat longer marginal. Tergite 5 contrastingly dull black, Tergite 6 dull brown. Sternite 1 not sclerotized, lacking bristles. Sternites 2 with fine pale hairs in middle, a pair of long apical bristles, sternites 3–4 with longer dense black. Male terminalia as in Fig. 31. Cerci whitish, with long white bristles, tips dorsally not fused (not forming a plate); epandrium with base of surstyli brown.

Female. Favoris shorter; colour pattern on legs identical to male, especially the black dorsal stripe on hind femur. Sternites 2 and 3 with short white bristles. Only hind trochanter with bristles. Femora with only short ventral bristles. Hind femur with 2 dorsal, 2 ad and some weaker pd bristles; no strong posterior bristles in apical half like in male.

Remarks. Thinophilus nigrilineatus sp. nov. is closely related to the Australasian T. constrictus Parent, 1932 described from Buru island ( Indonesia, Maluku Islands). However, there are numerous small differences such as the antennae that are yellow in T. constrictus while brown in T. nigrilineatus sp. nov. The presence of a partly white arista is not mentioned in T. constrictus . The colour patterns of the fore and mid femur seems to be clearly different. In T. constrictus I quote Parent (1932b): “Fémur I noirci en partie sur le quart basilaire, III sur le cinquième apical, plus longuement à la face dorsale, l’extrême apex excepté. Tibia II noir sur le 1/6 basilaire, la racine exceptée”. This means that the fore femur is black on basal quarter only, in T. nigrilineatus it is black on basal 2/3. Colour of mid femur is not mentioned (though femur is present in the type because other characters are given), it is supposed to be yellow, but largely black in T. nigrilineatus . There is a very similar pattern of colouration of the hind leg as can be seen in the quote above. The ventral bristles on the fore femur are shorter than the femur is wide, they are at least as long at base of femur and much longer on apical half of femur in T. nigrilineatus . The mid femur has short ventral bristles, in T. nigrilineatus they are nearly as long as femur is wide. The mid tibia bears numerous strong bristles (tibia tout au long de sa face ventral avec une herse de chètes noirs, robustes, plus longs que le travers) in T. constrictus , there are numerous but fine ventral bristles in T. nigrilineatus sp. nov.

Parent (1932b) mentions that the hind femur is without remarkable bristles dorsally, while there are 2 distinct dorsals near middle and a dorsal preapical in T. nigrilineatus and there is no mention of a row of strong posterior bristles in apical half as in T. nigrilineatus . This character cannot have been overlooked. The hind femur is similarly curved but apparently much wider in T. constrictus ( Parent, 1932b: Fig. 8).

Bionomics. This robust species is found on mudflats with a high sand content. It is an indicator species for front mangroves and it was never observed in back mangrove yet.

Phenology. Thinophilus nigrilineatus sp. nov. is a rare species with no or a very low activity from May to October. Activity seems to start in November and was highest from January to March and that in both years of the MIP project.

RAFFLES BULLETIN OF ZOOLOGY 2018

Fig. 33. Thinophilus nitens Grootaert & Meuffels, 2001 , male habitus ( Malaysia, Pulau Tioman). (Photo: Maimon Hussin).

Distribution. Singapore, Thailand.

Thinophilus nigrilineatus sp. nov. is hitherto only known in Singapore from the replanted mangrove on Semakau island. It has been observed in southern Thailand too (Samoh & Grootaert, unpublished).

Thinophilus nitens Grootaert & Meuffels, 2001 (Fig. 33)

Thinophilus nitens Grootaert & Meuffels, 2001: 346 (Figs. 17–20). Type locality: Thailand, Ranong province, river near Wat Tapo Taram .

Material examined. SINGAPORE: 14 males, 17 females, Pulau Ubin, fresh water pools (fallow, 1°24′33.77″N,

Fig. 34. Thinophilus pallitarsis sp. nov., male habitus.

103°56′52.57″), 12 September 2005, (reg. 25340, Si1030, leg. PG); 1 male, 4 females, Pulau Ubin, fresh water pools , 12 September 2005, (reg. 25340, Si1031, leg. PG); SMIP & MIP material: 1 male, Semakau new, SMN1, mangrove , 7 March 2013 (reg. 29782, Ma3430, Mal.); 1 female, Semakau new, SMN2, mangrove, 17 January 2013 (reg. 29691, Ma2380, Mal.); 1 female, Semakau new, SMN2, mangrove, 27 June 2013 (reg. 29999, Ma5140, Mal.).

THAILAND: 2 males, Songkhla, 14 October 1999 (leg. P. Grootaert, RBINS) .

MALAYSIA: 1 male, 1 female, Tanjung Leman, Mersing District , Johor, 23 December 2005 (reg. 25460; Si 1355; leg. P. Grootaert) .

Diagnosis. Large (5 mm) metallic blue green shining species, without dull black spots on mesonotum. Palpus, antenna and legs including fore coxae, yellow. Apical two tarsomeres of all legs contrastingly darkened. Fore coxa anteriorly with long, soft white hairs and a long black bristle. Wing sometimes with a faint spot on cross vein Tp and on M 1+2. Cerci black, medially fused.

Bionomics. Grootaert & Meuffels (2000) described both Thinophilus nitens and T. setiventris as littoral marine species. In fact, they were found in a riverbed rather far from the sea. I now have evidence that both are fresh water species since I found T. nitens in large quantities in a marshy area fed by upwelling water from a nearby hill on Pulau Ubin. Though the site was only a few meters from the sea, they were only observed feeding and displaying in the fresh water area. The site was completely exposed to the sun during the Fig. 35. Thinophilus pallitarsis sp. nov., male. A, Antenna; B, Mid femur; C, Hind femur; D, Fore tarsomeres dorsally; E, Fore tarsomeres laterally; F, Fore coxa, femur, and tibia.

day and large numbers of Tachytrechus tessellatus Macquart (a widespread Old World tropical species belonging to the Dolichopodinae ), a generalist known from rain drainage channels also occurred in the area.

The records in the replanted mangrove on Semakau Island were probably due to a sudden population increase after heavy rain fall in the nearby fallow. Here, T. tessellatus was also present.

Distribution. Singapore: Semakau Island, Pulau Ubin, Thailand (Ranong prov.), Malaysia (Pulau Tioman), Singapore and China (Yunnan).