Lydella gannanensis, Liu & Zhang & Xi, 2023

Liu, Shidie, Zhang, Chuntian & Xi, Xinqiang, 2023, Two new species of Eryciini (Diptera: Tachinidae) from the Eastern edge of the Qinghai-Tibetan Plateau, China, Zoological Systematics 48 (2), pp. 184-190 : 187-190

Lydella gannanensis sp. nov. ( Figs 11–20 )

Diagnosis. Frons 0.34–0.37 times of head width or 1.1–1.2 times of eye width, frontal vitta slightly wider than fronto-orbital plate at middle, ocellar setae proclinate; occiput mostly with two rows of black setulae behind postocular setae, antennal scape erect, scutellum with 4 pairs of marginal setae, apical scutellar setae crossed and half-erected. Base of R 4+5 with one setula dorsally and ventrally, vein M from bend to crossvein dM-Cu about equidistant between bend and hind wing margin; fore claw slightly longer than or equal to 5th tarsomere, mid tibia with 2–4 anterodorsal setae; abdominal tergites 3 and 4 each with 2 median discal setae, venter of male tergites 4 with two large sexual hair patches of appressed hairs.

Description. Body length ( Figs 11–12 ) 7.2–8.0 mm.

Male. Head ( Figs 13–14 ). Black in ground color. Eye bare, frontal vitta, parafacial, gena and occiput covered with white pruinosity. Lunule black. Antenna dark brown, palpi prementum gleaming black. Frons 0.34–0.37 times of head width or 1.1–1.2 times of eye width, frons approximately as long as facial height, frontal vitta nearly parallel and slightly wider than fronto-orbital plate at middle, parafacial at middle about 2 times as wide as antenna, gena height 0.2–0.3 times of eye height, face sunken below antenna, lower margin of face not protruding forward, not seen in profile. Proclinate ocellar setae welldeveloped, inner vertical setae about as long as eye height, postocular setulae long and slightly shorter than outer orbital setae. Eight inclinate frontal setae, lowest one descending to level of arista base, and two orbital setae reclinate, fronto-orbital plate with a row of seta-like hairs and some short black hairs on outer surface. Facial ridge with setae only on lower 1/5, vibrissa inserted below at level of lower of face, a row of 4–5 subvibrissae about 0.4 times as long as vibrissa. Occiput with white hairs and two rows of black setae behind postocular setulae. Antenna with postpedicel about 3 times as long as pedicel, scape with a hook-like prolongation basally, arista thickened from base to apical 1/2, first aristomere as long as diameter, second aristomere 2 times as long as diameter. Palpus stick-like, about as long as postpedicel. Prementum 1.5–2.0 times as long as wide, labellum large.

Thorax ( Figs 11–12 ) black with brownish gray pruinosity, 4 narrow dark longitudinal vittae on presutural scutum, 5 narrow dark longitudinal vittae on postsutural scutum, inner vittae ending to front 2/5 of postsutural scutum, scutellum black. Three presutural and 3 postsutural acrostichal setae, 3 presutural and 4 postsutural dorsocentral setae, 1 presutural and 3 postsutural intra-alar setae, 3 supra-alar setae, first one as long as notopleural seta and longer than postsutural intra-alar seta, postpronotal lobe with 3 setae arranged nearly in a straight line and anterior one located between inner two setae, scutellum with a pair of discal setae and 4 pairs of marginal setae, half-erected apical scutellar setae crossed and slightly longer than scutellum, lateral scutellar setae 0.5–0.6 times as long as subapical seta; prosternum setose on both sides, proepisternum bare, anepisternum with 1–3 setae anteriorly and a row of 5–6 setae posteriorly. anepimeron with one setae, weak, katepisternum with 3–4 setae, katepimeron and anatergite bare. Wing hyaline and brownish, tegula and basicosta black, calypters white, its margins yellowish, relative length of 2nd, 3rd and 4th costal sectors approximately in ratio of 1: 2: 1, 2nd and 3rd costal sections bare ventrally, costal spine about as long as crossvein r-m, base of R 4+5 with one setula dorsally and ventrally, which is about as long as crossvein r-m, vein M blunt at bending, vein M from bend to crossvein dM-Cu about equidistant between bend and hind wing margin. Halter brownish yellow on basal half and dark brown on distal half. Legs dark brown, pulvilli yellowish, fore claw longer than or equal to 5th tarsomere, fore tibia with a row of short anterodorsal setae, two posterior setae, one preapical anterodorsal and one preapical dorsal seta, one long preapical anteroventral seta. Mid femur with 2–4 strong anterior setae, two preapical posterodorsal setae, mid tibia with 2–4 anterodorsal setae, two posterior and one ventral setae (lowest one smaller). Hind tibia with 2 anterodorsal (one strong), 3 posterodorsal and 2 ventral (upper one short) setae, 2 preapical dorsal setae, 1 preapical anteroventral seta, preapical posteroventral setae absent.

Abdomen ( Figs 11–12 ) elongate ovate, black in ground color, covered with yellowish gray pruinosity, a black median vitta on tergites. Mid depression of syntergite 1+2 extending to its posterior margin, syntergite 1+2 and tergite 3 each with 2 median marginal and one pair of lateral marginal setae, tergite 3 with 2 median discal setae, lateral discal setae absent; tergite 4 with a row of marginal setae and 2 median discal setae; tergite 5 with many irregular discal setae and a row of marginal setae. Tergites 4 of male each with two large sexual hair patches of appressed hairs ventrally. Sternite 5 nearly square, its lateral lobe with strongly sclerotizedprotruding on inner surface, apex of lateral lobe bluntly round with densely short bundle-like setulae, median V-shape cleft about 3/5 length of sternite 5 as Fig. 15 . Male terminalia ( Figs 16–20 ). Cerci slender, nearly parallel, pointed at apex, narrowly separated on base 2/ 5 in caudal view, in lateral view cerci hook-like bent ventrally at apex, narrowed to apex. Surstylus slender, about as long as cerci, slightly pointed at apex in caudal view, outer edge concave on apical 1/ 4 in caudal view, blunt at apex in lateral view. Pregonite larger, with 3-5 setae at basal half on dorsal surface; postgonite with protruding; epiphallus with small protruding; basiphallus plate-like; distiphallus rather long, distinctly sclerotized, weakly expanded in lateral view; acrophallus sharp at apex and outer rim exceed largely behind part of distiphallus.

Female. Unknown.

Material examined. Holotype ♂ ( SYNU), Zhouqu , riverside, 204 Provincial Highway (32°19′N, 102°15′E; elev. 3406 m), Erhai , Luqu, Gannan, Gansu, China, 26.VIII.2021, Shidie Liu leg. Paratypes. 1♂ ( SYNU), same data as holotype. 1♂ ( SYNU), Azi Research Station of Alphine Meadow and Wetland Ecosystems of Lanzhou University (33°40′N, 101°52′E; elev. 3604 m), Maike , Maqu, Gannan, Gansu, China, 1–2.VIII.2021, Shidie Liu leg.

Distribution. China (Gansu).

Etymology. The specific epithet is taken from the typical locality, Gannan Prefecture, Gansu Province, China.

Remarks. The new species is similar to L. acellaris Chao & Shi, 1982 from China (Tibet), but distinguished from the latter by having narrower frons of male, occiput with two rows of black setulae behind postocular setulae, postpedicel of male shorter, about 3 times as long as pedicel, arista thickened from base to near apical 1/2, mid tibia with 2–4 anterodorsal setae, apex of cerci pointed and separated lobe of cerci wider in caudal and lateral view. And this new species is also close to L. stabulans Meigen, 1824 distributed in Europe and Russia ( Mesnil, 1955: 436), but different from the latter by having wider frons in male, relative length of 2nd, 3rd and 4th costal sectors approximately in ratio of 1: 2: 1, vein M from bend to crossvein dM-Cu about equidistant between bend and hind wing margin, mid tibia with 2–4 anterodorsal setae, hind tibia with 2 anterodorsal (one strong), 3 posterodorsal setae.

Funding This research was supported by the National Nature Science Foundation of China to Chuntian Zhang (31970443, 31750002) and to Xinqiang Xi (32022409, 31870417).

Acknowledgements We are thankful to the two anonymous reviewers and the editor Fuqiang Chen for their critical review. Our special thanks are extended to H. Shima, Kyushu University Museum, Kyushu University, Fukuoka, Japan, J.E. O’Hara, Agriculture and Agri-Food Canada, Ottawa, Canada, H.-P. Tschorsnig Staatliches Museum für Naturkunde, Stuttgart, Germany, the late C.M. Chao, Institute of Zoology, Beijing, China, J. Ziegler, Museum für Naturkunde, Berlin, Germany, and their assistance for the references. And we are grateful to Zixuan Huang, School of Life Science, Nanjing University for collecting the samples.

Figures

Figures 11–18. Lydella gannanensis sp. nov., male. 11–12. Body in dorsal and lateral views. 13–14. Head in anterior and lateral views. 15. Sternite 5. 16–17. Cerci, surstyli and epandrium in lateral and caudal views. 18. Bacilliform sclerite, ejaculatory apodeme, hypandrium, phallapodeme, pregonite, postgonite, basiphallus, distiphallus, epiphphallus, and acrophallus in lateral view. Scale bars: 11–14=1.0mm, 15–18 =0.2mm.

Figures 19–20. Lydella gannanensis sp. nov., male terminalia. 19. Lateral view. 20. Caudal view.