Thinophilus dongae, Grootaert, Patrick, Tang, Chufei & Yang, Ding, 2015

Grootaert, Patrick, Tang, Chufei & Yang, Ding, 2015, New species of Thinophilus Wahlberg (Diptera: Dolichopodidae) from mangroves in southern China (Shenzhen), Zootaxa 3956 (4), pp. 547-558 : 548-551

Thinophilus dongae sp. nov.

( Figs 1–5 )

Diagnosis. Small species with entirely yellow fore coxae; mid and hind coxae brown with yellow apex. Legs yellow, only tarsomere 5 of all legs pale brownish. Fore coxa with long black bristles. Wing brownish tinged, without spots. Fore femur with short, inconspicuous ventral bristles; fore tibia without ventral spinules, only a row of bristles. Mid and hind femora without long ventral bristles. Mid femur with a long black preapical av and hind femur with 2 ad. Four equally long dc. Antenna yellow, pedicel and postpedicel faintly brownish dorsally. Surstylus pale brown, 1/3rd length of abdomen; cercus shorter than surstylus, yellow with yellowish bristling.

Description. Male. Body length 5.1 mm; wing length 4.2 mm. Head. Frons and face with shiny dark metallic green ground colour. Face slightly narrower than length of postpedicel. Clypeus nearly half as long as epistoma, slightly broader than long, hardly protruding. Postcranium shining dark metallic green; 2 long divergent ocellars; 2 convergent proclinate verticals, shorter than ocellars; 2 very short postocellars; 2 postverticals, much stronger and longer than, and not in row with upper postoculars. Upper and lower postoculars uniseriate, short, black. Antenna yellow, pedicel and postpedicel dorsally faintly brown. Postpedicel rounded, as long as wide. Arista dorsal ( Fig. 3 ), 3X as long as antenna, black, very shortly pubescent; basal article very short. Palpus yellow, bearing few black bristly hairs. Proboscis dark brown. Thorax and scutellum shiny dark metallic green, with coppery and purple reflections. No dull black spots. Acr lacking; 4 equally long dc, preceded by short bristle. Scutellum with 2 marginals, without lateral hairs; 2 pale upper and 2 black lower propleural bristles. Legs. Fore coxa yellow; mid and hind coxae dark brown, both yellowish at tip. Legs yellow, only tarsomere 5 of all legs brownish. Fore leg. Coxa anteriorly with long black bristles. Fore femur ventrally with short inconspicuous bristles; 2 short preapical pv. Tibia slightly shorter than femur, with short ad on basal quarter; ventrally without spinules, ventral bristles at most slightly longer than usual. Length of femur, tibia and tarsal segments (in mm): 1.67: 1.33: 0.50: 0.25: 0.20:: 0.17: 0.25. Mid leg. Coxa with long, black exterior bristle near middle; long black anterior bristles. Femur ventrally with minute bristles; long black preapical av at apical fifth, longer than width of femur. Tibia as long as femur; 2 strong ad and crown of long apical bristles.

Length of femur, tibia and tarsal segments (in mm): 2.00: 2.00: 0.50: 0.42: 0.30: 0.20: 0.30. Hind leg. Coxa with black exterior bristle. Femur with row of very short ventral to posteroventral bristles; 2 short anterodorsal bristles. Tibia with 1 ad, 2 dorsal and crown of apical bristles. Length of femur, tibia and tarsal segments (in mm): 2.0: 2.33: 0.50: 0.42: 0.30: 0.25: 0.25. Wing uniformly brownish tinged, without spots. Veins brown. Tp straight, apical part of M3+4 twice as long as Tp. Anal vein not reaching wing margin. Halteres, squamae and ciliation white. Abdomen shining dark metallic green. Hairs and hind-marginal bristles on tergites short, black. Sternites with short pale bristles. Terminalia ( Figs 4–5 ). Dorsal surstylus pale brown; with 3 long bristles ventrally near middle. Ventral surstyli asymmetrical: left ventral surstylus with dorsal bristle. Right ventral surstylus with apical bristle. Phallus long strapshaped. Cerci yellow with yellowish hairs; 2 long, apical yellowish brown bristles; cerci dorsally fused on basal 2/3rds. Female. Body length 5.5 mm; wing length 4.9 mm. Larger than male. Face about as wide as depth of postpedicel. Clypeus 1/3rd length of face, bulging. Legs bristled as in male, but ventral hairs on fore tibia shorter.

Material examined. HOLOTYPE ♂, labelled: CHINA, Guangdong prov., Shenzhen, Longgang Yanba (114°51'E 22°65'N), 13.ix.2014, along creek in front mangrove (reg. 34011, leg. P. Grootaert & I. Van de Velde; CAU). PARATYPES: 5 ♂, 5 ♀, same provenance as holotype ( RBINS); 3 ♀, same provenance (leg. Y. Zhu, Shanghai).

Etymology. The species is dedicated to Dr. Hui Dong (Shenzhen) for her very kind hospitality during our collecting trip in Shenzhen.

Discussion. The entirely yellow fore coxae, absence of dull spots on the mesonotum, absence of spots on the wings, and simple fore tarsomere 1 lead the new species to couplet 14 in the key of Yang et al. (2011). However the species quoted there in the key have long white bristles on the fore coxae ( T. seticoxis Becker , T. lamellaris Zhu, Yang & Masunaga and T. clavatus Zhu, Yang & Masunaga ) or a single black bristle among the white bristles ( T. nitens Grootaert & Meuffels ). Thinophilus dongae sp. nov. has only black bristles on the fore coxae and in this way easily separated. See below for discussion and the modified key ( Yang et al. 2011) under T. zhuae sp. nov.

Thinophilus dongae sp. nov. is very similar in morphology to an un-described species from mangroves in Singapore, here referred to as Thinophilus pr simplex. As can be seen in the neighbour joining tree ( Fig. 16 ) it clusters with a bootstrap value of 98, but the pairwise distance is 14 %.

Biology. This small species was found foraging on the mud flats directly exposed to the sun along a small creek.

Figures

FIGURE 16. Neighbour-Joining tree of the COI barcodes of Thinophilus from the South China Sea with bootstrap values indicated at the nodes. The scale of the genetic distance is 2 %.

FIGURES 1 – 2. Thinophilus dongae sp. nov. habitus. 1, male; 2, female.

FIGURES 3 – 5. Thinophilus dongae sp. nov. male. 3, antenna; 4, hypopygium lateral view; 5, hypopygium dorsal view. Abbreviations: c: cercus; ds: dorsal surstylus; hy: hypandrium; vs: ventral surstylus. Scale bar = 0.125 mm.