Parorthocladius tyurkini Makarchenko et Makarchenko

Makarchenko, Eugenyi A. & Makarchenko, Marina A., 2015, A review of the genus Parorthocladius Thienemann, 1935 (Diptera: Chironomidae: Orthocladiinae) from the Russian Far East, Zootaxa 3974 (3), pp. 413-423 : 419-421

Parorthocladius tyurkini Makarchenko et Makarchenko , sp. nov.

( Figs. 18–28 )

Material. Holotype: adult male, extracted from mature pupa, Russian Far East, Chukotka Autonomous Okrug, Iul’tinsky District, Egvekinot Village region, unnamed stream of Seutakan Lake basin, 20.VII. 1976, leg. E. Makarchenko. Paratypes: 4 mature pupae (males) and 2 larval skins, same data as holotype.

Adult male (n=2). Total length ca 3 mm.

Head. Eyes pubescent. Temporal setae 9–10, including 5–6 verticals and 3–4 postorbitals. Clypeus with 11 setae. Antenna with 13 flagellomeres and well developed plume; AR 0.69–0.73. Palp with 5 palpomeres. Length of distal 4 palpomeres (in µm): 40, 72, 64, 100 (n=1).

Thorax. Scutum with 3 dark brown stripes in lighter background. Antepronotum with 1–2 lateral setae. Dc 7– 8; Pa 4; scutellum without setae.

Wing. Not spread.

Legs. LR1 0.62.

Hypopygium ( Figs. 18–23 ). Tergite IX and anal point with 28–38 setae. Anal point 20–24 µm long and 16–20 µm wide near apex. Laterosternite IX with 1–2 setae on each side. Transverse sternapodeme 92–100 µm long, with triangular oral projections. Virga absent. Gonocoxite 252–304 µm long; dorsal and ventral parts of inferior volsella triangular or rounded-triangular, both covered with microtrichia and setae ( Figs. 18–19, 22 ). Superior volsellae absent. Gonostylus 104–116 µm long, without crista dorsalis ( Fig. 23 ); megaseta 12 µm long.

Pupa (n=5). Total length 2.9–3.1 mm. Colouration brown. Exuviae brownish, transparent.

Cephalothorax. Frontal apotome without tubercles and frontal setae. Thoracic horn absent but present pore and 3 precorneals (length in µm): Pc1 32, Pc 2 28–32, Pc3 24; precorneals weak and hair-like, arranged one behind the other. Distance between Pc1 and Pc 2 14–28 µm; distance between Pc2 and Pc 3 6–34 µm. Antepronotum with 2 middle setae and 1 lateral seta. Dorsal surface of mesonotum rugose, in anterior 1/3 with row of pointed tubercles. Three dorsocentrals hair-like; distance between Dc1 and Dc2 148 µm; between Dc2 and Dc 3 10–22 µm.

Abdomen. Tergite I without shagreen. Tergite II with group of small spinules at posterior margin or sometimes naked. Tergite III with posterior and anterior groups of spinules; posterior group wider and with larger spinules than in anterior part; between these groups shagreenation with very rare spinules. Shagreenation of tergites IV–VII same or similar to that of tergite III but areas of shagreen more extensive and broader, anterior and posterior groups interconnected as shown in Fig. 24 . Tergite VIII with strip of small spinules along posterior edge and with group of spinules in anterior half of tergite. Sternites I–IV, VIII–IX without shagreen. Sternites V–VI with small spinules in antero-median part and with stripe of spinules in posterior part. Sternite VII with sparse spinules in antero-median part. Segment I with 2 pairs of lateral setae, segments II–VIII with 3 pairs of lateral setae; all lateral setae short and hair-like. Anal lobe 260–296 µm long. Male genital sac overreaching anal lobe. Anal macrosetae 80–88 µm long. Anal macrosetae length/anal lobe length 0.30–0.31.

Fourth instar larva (2 larval skins).

Head. Head capsule dark brown. S I–IV of labrum simple and hair-like. Pecten epipharyngis consisted of 3 scales. Premandible 64 µm long, in apical part expanded and rounded, with 1 tooth ( Fig. 28 ). Antenna with 5 segments, length of segments 1–5 (in µm): 48: 16: 5: 8–9: 6–7; segment 3 shorter than segment 4; three ring organs in proximal 1/4 of basal segment; apex of segment 2 with stylus 8 µm long; lauterborn organs weak or absent; blade ending at apex of segment 5 ( Fig. 27 ); AR 1.33. Mandible 92–96 µm long, with 3 equal inner teeth and 1 apical tooth; seta subdentalis long and strong, with pointed apex ( Fig. 26 ). Mentum with broken apical part and 4 pairs of lateral teeth. Beard of ventromental plates consisted of a tuft of long setae ( Fig. 25 ). Procercus 8 µm long and 16– 20 µm wide, with 2 short lateral setae and 6 apical setae 220–260 µm long. Body segments only with simple setae.

Diagnostic characters. See the keys.

Remarks. In this paper, we did not plan the revision of all species of the genus Parorthocladius , but studying the larvae of P. tyurkini indicate that all abdominal setae are simple. Consequently, the generic diagnosis ( Cranston et al. 1983; Andersen et al. 2013) should be complemented with this character.

Etymology. The species is named in memory of Anatoly Tyurkin, for his help in accommodation and collecting the material in the Seutakan Lake of the Chukchi Peninsula.

Distribution. Known from the type locality in Seutakan Lake basin of Chukotka Region, the Russian Far East.

Figures

FIGURES 18 – 28. Parorthocladius tyurkini sp. nov., male (18 – 23), pupa (24) and larva of fourth instar (25 – 28). 18, hypopygium in dorsal view; 19, inferior volsella; 20 – 21, anal point; 22, gonocoxite and gonostylus in dorsal view; 23, gonostylus; 24, tergites I – IV; 25, mentum; 26, mandible; 27, antenna; 28, premandible. Scale bars: Figs. 18 – 23 — 50 µm; Fig. 24 — 200 µm; Figs. 25 – 28 — 20 µm.