Neozavrelia oyabeparvulus ( Sasa, Kawai, Ueno, 1988 )

Orel, Oksana V., 2021, Revision of the genus Neozavrelia Goetghebuer, Thienemann, 1941 (Diptera Chironomidae) from Eastern Siberia and the Russian Far East, with the description of new species, Zootaxa 4938 (3), pp. 251-297 : 278-279

Neozavrelia oyabeparvulus ( Sasa, Kawai, Ueno, 1988)

( Figs 77–87 )

Tanytarsus oyabeparvulus Sasa, Kawai, Ueno, 1988: 41 , Plate 7A. Comb. nov.

Tanytarsus okamotoi Sasa, 1989: 41–42 , Fig. 14 , Plate 7. Comb. nov., syn. nov.

Material examined. 8 males, RUSSIA, SAKHALIN OBLAST, Sakhalin Island, Korsakovsky District, Vavayskoye Lake , 5–15.vii.2004, leg. E. Makarchenko.

Description. Adult male (n=3). Total length 1.50–1.75 mm; wing length 1.11–1.12 mm. Total length/wing length 1.35–1.56.

Colouration. Ground colour of thorax, maxillary palpomeres, scutellum, abdomen and legs yellowish brown; halters yellowish; antenna, scutal stripes, median band on distal half of mesonotum and postnotum brown.

Head ( Figs 82–83 ). Frontal tubercles minute, 3 μm long and 4 μm wide. Temporal setae 8–10. Clypeus with 8–10 setae. Antenna with 13 flagellomeres, 570–600 μm long; ultimate flagellomere 220–225 μm. AR 0.60–0.63. Maxillary palpomeres 2–4 combined 290–325 μm long, their individual lengths (in μm): 35–45: 75–90: 75–90: 105–120. Antenna length/palp length 1.85–1.97.

Thorax. Acrostichals 11–16, dorsocentrals 4–6, prealar 1. Scutellum with 4 setae.

Wing width 0.29–0.33 mm ( Figs 84–85 ). VR 1.29–1.31. R with 16–20, R 1 with 4–6, R 4+5 with 7, M 1+2 with 17–27, M 3+4 with 4–6, Cu 1 with 3–11 setae, An with 8–13, Vf with 13–20 setae. Cell r 2+3, r 4+5, m 1+2, m 3+4 with setae. Brachiolum with 1 seta.

Legs (see Table 11). Apical curved tibial spur of fore leg 22–24 μm long. Combs of mid and hind tibiae separated; each comb bears straight or slightly curved spur, 14–22 μm (mid tibia) to 20–24 μm long (hind tibia). Basitarsus of mid leg without sensilla chaetica.

Hypopygium ( Figs 77–79 , 86–87 ). Anal tergite with H-shaped bands which reach base of anal point, central part of tergite IX covered with microtrichia and with 5–7 lateral setae on each side, free-microtrichia areas present on the sides of anal tergite bands. The anal point (22–24 μm long and 20 μm wide in the base and 16 μm wide on the apex) broad, parallel-sided or triangular form, rounded apically, dorsally covered with 8–12 strong spinulae (6–12 μm long), microtrichia and bearing 2–3 lateral setae on each side of the anal point ( Figs. 2–3 ). Gonocoxite 80–110 μm long, along the inner margin with 4 setae. The width of the transverse sternapodema 50 µm. Phallopodema 90 μm long. Superior volsella elongated oval-shaped (40–50 μm long, 26 μm wide), bearing 2 median setae and 1 strong inner seta on a tubercle, and 5–6 fine dorsal setae, microtrichia absent ( Figs 4–5 ). Digitus 16–22 μm long, reaching the apex of the superior volsella. Stem of the median volsella straight 26 μm long, bearing slender lamelliform setae; total length of the median volsella 40 μm. Inferior volsella curved and rounded apically, 72 μm long, with 10–18 setae. Gonostylus straight, 66–70 μm long and expanded at about median 20 μm. HR 1.21–1.57.

Pupa and larva unknown.

Remarks. According to Sasa (1989): “both species differ from each other in that spines on anal point are distributed on the entire dorsal surface in present species (they are situated only on the posterior margin of anal point in oyabeparvulus )”. In the specimens we found on Vavayskoye Lake, the length of the spines on the anal point varied from 6 to 12 μm ( Figs 78–79 ). When comparing photographs of hypopygium and the morphological description of these two species of obvious morphometric distinctive features were not revealed (see Table 12) (http://www. type. kahaku.go.jp/TypeDB/mediaDetail?cls=diptera&pkey=diptera-000126&lCls=m_diptera&lPkey=272738&detailln kIdx=0 and http://www. type.kahaku.go.jp/TypeDB/mediaDetail?cls=diptera&pkey=diptera-000146&lCls=m_dipt era&lPkey=272821&detaillnkIdx=0). Based on the above, we believe that Neozavrelia okamotoi ( Sasa, 1989) is a junior synonym N. oyabeparvulus ( Sasa et al., 1988) .

Distribution. Japan (Shou River) and Russian Far East—Sakhalin Island.

Figures

FIGURES 77–81. Details of the structure of hypopygium the male of Neozavrelia oyabeparvulus (Sasa et al.). 77—total view of hypopygium, dorsal view; 78, 79—tergite IX and anal point, dorsal view; 80, 81—superior volsella, ventral and dorsal view. Scale bar 50 μm.

FIGURES 82–87. The male of Neozavrelia oyabeparvulus (Sasa et al.). 82—maxillary palps; 83—antenna; 84, 85—wing; 86, 87—hypopygium. Scale bar 50 μm.

FIGURES 9–22. Details of the structure of the male of Neozavrelia kedrovaya sp. nov. 9—maxilar palp; 10—total view of hypopygium; 11, 12—anal point; 13—superior volsella; 16–18—gonostylus and inferior volsella; 19–21—tergite IX, lateral view; 22—thoracic horn. Scale bar 50 μm.

FIGURES 1–8. The male of Neozavrelia fengchengensis Wang, Wang. 1—frontal tubercles; 2—maxilar palp and clypeus; 3—antenna; 4—apical part of wing; 5, 6—total view of hypopygium; 7, 8—lateral view of hypopygium. Scale bar 50 μm.