Dichopygina tibetana Leng, Heller & Huang, 2018

Leng, Ruixin, Heller, Kai, Huang, Junhao, Ye, Lan & Wu, Hong, 2018, DNA barcoding of the genus Dichopygina, with a new species from China (Diptera: Sciaridae), Zoological Systematics 43 (1), pp. 18-26 : 24-26

Dichopygina tibetana Leng, Heller & Huang , sp. nov. ( Figs. 7–12 )

Material examined. Holotype, 1♂. China. Tibet, Bomi, Ganjing Guesthouse , light trap, 18 July 2014, leg. Jun Xu / Mei Qin ( SM02765 ) ( SCILA001-16 ) ( ZAFU) . Paratypes. 5♂, the same data as holotype ( SM02766–67 , SM02818–20 ) ( SCILA002-16 , SCILA003-16 , SCILA004-16 , SCILA005-16 , SCILA006-16 ) ( ZAFU].

Diagnosis. The new species and D. bernhardi are similar to each other in having a rather straight gonostylus with all megasetae at the apical half of the gonostylus and the flatter top of tegmen. However, D. tibetana differs in having larger wings (wing length 1.6–1.8 mm versus 1.4–1.7 mm) and fewer gonostylar megasetae (6–8 versus 10–13). By its number of gonostylar megasetae and basalmost megasetae longer than the others, D. tibetana also resembles D. duplics . However, the new species can be distinguished by its larger wings (wing length 1.6–1.8 mm versus 1.2–1.4 mm) and broader eye bridge (facets wide 4 versus 3). Furthermore, D. tibetana resembles D. perfecta by sharing the very similar arrangement of the gonostylar megasetae, while the later species may easily be recognized by its equally rounded tegmen.

Description. Colour. Thorax, abdomen, antennae and hypopygium brown; legs, palpus and wing veins yellowish brown; wings fumose. Antenna unicolour and yellowish brown.

Head. Eye bridge 4 facets wide. Antennal setae fine, dense, shorter than segment width ( Fig. 8 ). Length/width of flagellomere 4 of antenna 1.95–2.33; transition of basal part to neck pronounced; neck lengh/segment width 0.30–0.50, unicolour. Maxillary palpus 3-segmented, basal segment with 1 seta; 2nd segment with 6–8 setae; 3rd segment with 5–7 setae; sensillae present ( Fig. 10 ).

Thorax. Notum brown. Thoracic setae weak, white. Anterior pronotum with 4–6 setae, episternum 1 with 4–8 setae. Wings ( Fig. 7 ). Wing length 1.60–1.80 mm, width/length 0.43–0.46, R 1/ R 0.64–0.85, c/w 0.49–0.57. Membrane without macrotrichia. Venation weak, with faint stM; M-fork of normal shape; R 1 ending clearly before base of M-fork; bM, r-m bare. Halter bright, short. Legs. Foreleg: foretibia ( Fig. 10 ) with dense patch of setae and curved margin; claws untoothed; length of basitarsomere/length of foretibia 0.55–0.60; length of femur/length of metatarsus 0.56–0.86. Length of metatarsus/length of tibia: foreleg 1.17–1.48, hind leg 0.85–0.97. Length of hind tibia/length of thorax 0.95–1.16. Abdomen. Abdominal setae weak, sparse. Tergal setae white. Sternal setae white.

Hypopygium ( Figs 9, 12 ). Hypopygium 0.6–0.8 times as long as wide. Base of gonocoxites with normal, weak hairs; gonocoxites wide and strong, narrowly separated; inner margin of gonocoxites U-shaped; inner membrane of hypopygium bare. Gonostylus elongated, narrowed and curved; 1.0–1.3 times longer than wide; inner margin straight, or concave in ventral view; apex tapered. Apical tooth without internal structure, shorter than subapical megasetae; 1.0–1.3 times longer than broad. Awl-like setae absent. With 6–8 megasetae in the apical half of the gonostylus and the basalmost megasetae longer than the others. Position of basalmost megaseta 42–44% from apex. Whiplash-hair absent. Tegmen 0.70–0.75 times as long as broad, variable in shape, from subtrapezoidal to subtriangular, without sclerotized borders, with central process. Aeadeagal with apical structure and teeth.

Distribution. China (Tibet).

Etymology. This species is named after the Chinese province of its type locality, Tibet.

Funding The work is financially supported by the National Natural Science Foundation of China (31372244), the Science and Technology Department of Zhejiang Province (2013C32082) and Norwegian Taxonomy Initiative ( NTI) (Artsprosjektet, 70184228) .

Acknowledgements We are grateful to Ms. Valérie Lévesque-Beaudin (Guelph, Canada) for the loan of Canadian Dichopygina specimens and to Mr. Björn Rulik (Bonn, Germany) for making available the sequences of Finnish specimens on BOLD and assistance with the treatment of the Chinese sequences.

Figures

Figures 7–12. Dichopygina tibetana Leng, Heller and Huang, sp. nov., male. 7–11. Holotype (Sample ID: SM02765; Process ID: SCILA001-16); 12. Paratype (SM02766; SCILA002-16). 7. Wing, dorsal view. 8. The 4th flagellomere, lateral view. 9. Genitalia, ventral view. 10. Apex of foretibia, prolateral view. 11. Palpus, lateral view. 12. Left gonostylus, ventral view. Scale bars: 7=1.0mm; 8–12=0.1mm.