Thinophilus variabilis, Samoh & Satasook & Grootaert, 2017

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 : 30-34

Thinophilus variabilis sp. nov.

urn:lsid:zoobank.org:act:269414E1-124D-4113-9781-234E3E5340F9

Figs 36–40

Diagnosis

Medium-sized species with yellowish brown to brown fore coxa bearing black bristles. Fore tibia with a row of long ventral spine-like bristles over entire length of tibia. Wing brownish.

Etymology

The specific epithet refers to the variable colour of the legs. In some specimens the legs are yellow, in others brown to black.

Type material

Holotype

THAILAND: ♂, Laem Pho, Hat Yai , Songkhla Province, 7°09 ′ 15.9 ″ N, 100°28 ′ 03.6 ″ E, sweep netting, 27 Jun. 2015, A. Samoh leg. ( NHM-PSU ).

Paratypes

THAILAND: 6♂♂, 10 ♀♀, Ban Nua Nam, Phumriang, Chaiya, Surat Thani, 9°23 ′ 34.0 ″ N, 99°15 ′ 24.0 ″ E, sweep netting, 18 Apr. 2015, A. Samoh leg.; 2 ♂♂, 4 ♀♀, Ban Nua Nam, Phumriang, Chaiya, Surat Thani, 9°23 ′ 34.0 ″ N, 99°15 ′ 24.0 ″ E, sweep netting, 20 Apr. 2015, A. Samoh leg.; 5 ♂♂, 18 ♀♀, Ban Dato, Yaring, Pattani, 6°55 ′ 17.1 ″ N, 101°19 ′ 50.7 ″ E, sweep netting, 12 Apr. 2015, A. Samoh leg. ( NHM- PSU); 2 ♂♂, 1 ♀, same collection data as for holotype ( RBINS).

Description

Male ( Fig. 36 )

LENGTH. Body 2.7 mm; wing 2 mm.

HEAD. Frons and face with shiny dark metallic green ground colour, but epistoma above with purplish reflections. Face above as wide as length of postpedicel, near middle narrower than postpedicel. Clypeus a third of length of epistoma. A pair of long divergent black ocellars. Two very short postocellars. A pair of convergent proclinate verticals, as long as ocellars. Vertex not excavated, dull. A pair of converging postverticals, only a little longer than postoculars, and not in row with upper postoculars. Postoculars uniseriate and black throughout; below neck with a transverse row of 4 black bristles longer than postoculars. Antenna yellowish; pedicel darker than postpedicel. Arista subdorsal, 3 times as long as antenna, brown, with short pubescence on basal half, longer diverging pubescence on apical half. Basal article short, brown; rest of arista paler. Palpus yellow, with short black bristly hairs. Proboscis brown.

THORAX. Thorax and scutellum shiny dark metallic green, with coppery and purple reflections. No dull black spots. Bristles on thorax black. Acr lacking; 4 almost equally long dc, prescutellar one longest and outside row. Scutellum with 2 marginals and a short lateral bristle. One short black propleural above and 2 longer black propleurals below.

LEGS. Yellow to brown, including all tarsomeres. Fore coxa completely yellow, sometimes with sides brownish or completely brown; mid and hind coxae brownish, apices pale. Fore coxa anteriorly with long curved black bristles. Trochanter with a long black bristle. Fore femur a little wider than mid femur, especially on basal half; ventrally near base a few black bristles that are shorter than femur is wide; a posteroventral row of bristles over entire length, near base as long as femur is wide, on apical half longer ( Fig. 36 ). Fore tibia shorter than femur, a ventral row of bristles over entire length, bristles as long as tibia is wide only on apical half. Mid coxa with a long black exterior bristle near middle as long as coxa is long; anteriorly with long black bristles. Mid femur with an av bristle at apical quarter; 4 pv bristles on apical quarter. Mid tibia as long as femur; with 2 ad, 2 shorter pd and apical crown of bristles. Hind coxa with a short and a long exterior bristle. Hind femur only a little wider than mid femur; ventrally with a row of black bristles half as long as femur is wide; near middle with an ad and an preapical at apical fifth; 3 preapical pv as long as femur is wide and 3 shorter av.

WINGS. Brownish tinged, without spots. Tp straight, apical part of M 3+4 2.5 times as long as Tp. Anal vein not reaching wing margin.

ABDOMEN. Shining dark metallic green. Hairs and hind-marginal bristles on tergites black. Sternites with black hairs.

TERMINALIA ( Figs 38–40 ). Phallus long, strap-shaped. Cerci pale yellowish, surstyli brown, epandrium brown. Cerci pale yellowish, surstyli brown, epandrium brown. Cerci not fused, with very long subapical bristles.

Female ( Fig. 37 )

LENGTH. Body 2.4 mm long, wing 2.3 mm long.

BODY. Stouter than male, otherwise similar except for following characters: fore femur with only a row of pd near tip; tibia with only short ventrals.

Distribution

Southern Thailand (Gulf of Thailand).

Remarks

Thinophilus variabilis sp. nov., a small species, differs from T. minutus sp. nov. in having distinct ventral bristles on all femora. Most characteristic in T. variabilis sp. nov. is the row of long ventral bristles on the fore tibia, which is absent in T. minutus sp. nov. Coxae and femora can vary in colour from yellow to brown and even dark brown. Such a variation in colour is fairly unusual in Thinophilus and might be due to the preservation of the specimens in denaturised ethanol. The species seems to be widespread in peninsular Thailand.

Figures

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

Fig. 37. Thinophilus variabilis sp. nov., ♀, habitus.

Figs 38–40. Thinophilus variabilis sp. nov., ♂, terminalia. 38. Genital capsule, ventral view. 39. Genital capsule, lateral view. 40. Cerci, dorsal view.