Polypedilum

Orel, Oksana V., 2018, New species of the non-biting midges of Tribe Chironomini (Dptera, Chironomidae) from the Bolshekhekhtsyrsky Reserve (Russia, Khabarovsk Territory), Zootaxa 4461 (2), pp. 269-276 : 272-273

Polypedilum (s. str.) servatum sp.n.

( Figs 5 , 16–19 )

Type material. Holotype: 1 male, Russia, Khabarovsk Territory, Bolshekhekhtsyrsky Nature Reserve, basin of the Chirka River, Golovina Stream , 13.VI.2015, leg. N.M. Yavorskaya.

Derivatio nominis. The species name is from Latin adjective servatum = reserved, referring to the place of collection of the type materials.

Diagnostic characters. The new species has the following combination of characteristics: wing length 1.9 mm, without spots and setae on the surface; mesonotal stripes and postnotum dark brown, ground color of thorax brown, scutellum, halters, abdomen and legs yellowish; AR 1.45; humerals 5; anal point spear-shaped; superior volsella inwardly curved near of the base, bearing 1 lateral seta near the base, 4 basal setae and covered with microtrichia; gonostylus slightly widened in the middle, the inner margin is slightly concave; HR 1.17.

Description. Adult male (n=1). Total length 3.5 mm. Wing length 1.9 mm. Total length/wing length 1.89.

Coloration is brown. Antenna, mesonotal stripes and postnotum dark brown; ground color of thorax brown; scutellum, halteres, abdomen and legs yellowish.

Head. Head width 464 µm. Frontal tubercles absent. Antenna 1134 µm long. Ultimate flagellomere 672 µm long. AR 1.45. Verticals 12/14. Clypeus with 12 setae. Lengths of last 4 palpomeres (in µm) of maxillary palp: 48; 88; 120; lost.

Thorax. Antepronotals 0, acrostichals 21, humerals 5, dorsocentrals 14, prealars 6, supraalars 0. Scutellum with 16 setae.

Wing. Width 0.57 mm. Veins R with 17/20, R 1 15/18 setae, R4+5 with 28/30 setae. Squama with 13 setae; brachiolum with 1 seta. VR 1.3.

Legs. Scale of fore tibia elongated-pointed ( Fig. 16 ). Spurs of middle and hind tibia 44 µm long. Lengths and proportions of legs as in Table 2.

Hypopygium ( Fig. 5 , 17–19 ). Tergite IX with 8 median setae. Laterosternite IX with 2–3 setae. Anal point spear-shaped, 65 µm long, 12 µm wide, with 10/14 lateral setae at the base. Gonocoxite 143 µm long, with 4/5 inner setae. Transverse sternapodeme 37 µm long. The basal portion of the superior volsella 24 µm long and 27 µm wide, with 4 basal setae and covered with microtrichia, and 1 lateral seta located near the base; apical part of the superior volsella 61 µm long; RSVo 2.6. Inferior volsella 112 µm long, with 15/17 strong setae. Gonostylus 122 µm long and 37 µm wide, slightly widened in the middle, the inner margin is slightly concave and has 1 apical seta and 3/4 subapical setae. HR 1.17.

Female, pupa and larva unknown.

Remarks. The adult male of P. (s. str.) servatum sp.n. is most similar to P. (s. str.) tochibicolor Niitsuma, 1991, in the structure of hypopygium and morphometric parameters, but differs from latter P. (s. str.) tochibicolor Niitsuma by the color of thorax (scutellum and halters yellowish), the form of anal point (spear-shaped) and the basal setae of the superior volsella located in the distal half or almost the entire length. While in the males P. (s. str.) tochibicolor has dark brown thorax including halters, anal point narrow, parallel-sided, basal setae on superior volsella situated in distal third. Adult male of P. (s. str.) servatum sp.n. in form of anal point very similar to two Chinese species— P. (s. str.) adustalum Zhang, Wang, 2017 and P. (s. str.) constrictum Zhang, Wang, 2017, but differs from the latter by a combination of the characters that are given in the Table 3.

Distribution. Known only from the typical habitat—Bolshekhekhtsirsky Nature Reserve (Khabarovsk Territory).

Figures

FIGURES 1–5. Details of hypopygium structure of the male of Polypedilum (s. str.) odyrensis sp.n. (1–4) and Polypedilum (s. str.) servatum sp.n. (5). 1, 5—dorsal view of hypopygium; 2—tergite IX and anal point in dorsal view; 3, 4—superior volsella in dorsal view. Scale bars 50 µm.

FIGURES 16–19. The male of Polypedilum (s. str.) servatum sp.n. 16—apex of fore tibia; 17–19—hypopygium. Scale bars 50 µm.