Bryophaenocladius aestivus (Brundin)

Du, Jing, Wang, Xin-Hua & Saether, Ole, 2011, Redescriptions of species of Bryophaenocladius Thienemann, 1934 (Diptera: Chironomidae) described by Brundin (1947), Zootaxa 2743, pp. 40-48 : 41-42

Bryophaenocladius aestivus (Brundin)

( Figures 1–2 )

Eudactylocladius aestivus Brundin, 1947: 30 , figure 56.

Bryophaenocladius aestivus (Brundin) : Ashe & Cranston 1990: 161.

Type material. Lectotype, male, here designated, SWEDEN: Småland, Lake Skärshultsjön, mixed forest at shore, net, 16.viii.1943, (together with B. propinquus ). Paralectotype, male: as lectotype.

Diagnostic characters. The male imago is characterized by a long anal point with rounded apex and well developed basal shoulders; coarse punctation of wing membrane, long costal extension, squama with several setae; acrostichals well developed and decumbent; inferior volsella curved and digitiform, and gonostylus curved.

Male imago (n = 2). Total length 2.16–2.82 mm. Wing length 1.28–1.48 mm. Total length / wing length 1.69– 1.91. Wing length / length of profemur 2.35–2.38. Coloration dark brown.

Head. AR 1.18–1.36. Ultimate flagellomere without apical seta. Temporal setae 6–7, including 2–3 inner verticals, 1–2 outer verticals, and 2–3 postorbitals. Clypeus with 9–15 setae. Tentorium 112–154 Μm long. Stipes 92– 134 Μm long. Palpomere lengths (in Μm): 29–30; 42–44; 84–95; 88–100; 88–98. Third segment without finger-like apical extension.

Thorax. Dorsocentrals 16–17, antepronotals 4, acrostichals 8–11, prealars 4–5, scutellars 6–8.

Wing. Anal lobe not developed. Relatively coarse punctation easily visible at 40x magnification. VR 1.22– 1.29. R2+3 ends at 1/2 distance between R1 and R4+5. Costal extension 48–58 Μm long. Brachiolum with 1 seta; R with 7–10 setae; R1 with 4 setae; remaining veins bare. Cu1 slightly curved. Squama with 7 setae.

Legs. Spur of front tibia 40–50 Μm long, spurs of middle tibia 31–38 Μm and 13–20 Μm long, of hind tibia 48– 56 Μm and 20–24 Μm long. Hind tibial comb with 15–16 setae. All tibial spurs with lateral denticles. 4th tarsomere obviously longer than 5th tarsomere in fore and hind legs, and slightly longer than 5th tarsomere in mid leg. Lengths and proportions of legs as in Table 1.

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV

p1 538–590 624–730 345–418 220–254 108–162 106–115 82–86 0.55–0.57 2.82–2.92 3.16–3.37 p2 557–615 586–656 278–303 143–164 106–131 67–90 77–82 0.46–0.48 3.38–3.62 4.11–4.19 p3 576–631 682–795 365–426 191–230 162–197 96–115 77–90 0.54–0.54 2.93–3.08 3.35–3.45 Hypopygium ( Fig.1–2 ). Anal point well developed, 25 Μm long, 15 Μm wide, with rounded apex and straight well developed basal shoulders. Tergite IX with 12–18 setae. Laterosternite IX with 6–8 setae. Phallapodeme 84 Μm long; transverse sternapodeme 80–88 Μm long. Gonocoxite 194–202 Μm long. Inferior volsella digitiform, curved, with several setae. Gonostylus curved, 76–88 Μm long; crista dorsalis reduced, megaseta 9–14 Μm long. Virga consisting of 8–9 spines, 20–22 Μm long. HR 2.20–2.66, HV 2.45–3.75.

Remarks. Brundin (1947) gives the leg ratio as 0.60 and squama with at least 4 setae, while we find slightly lower leg ratio and squama with 7 setae.

Distribution and ecology. The species is known from Denmark, Finland, France, Germany, Italy, Norway, Sweden, Russia and USA (Alaska, Pennsylvania), with a doubtful record from Madeira ( Saether & Spies 2004, Oliver et al. 1990). Oliver & Dillon (1997: 618) inform that in contrast to other members of the genus the larvae of this species may live in small streams and standing water.

Figures

FIGURES 1 – 2. Bryophaenocladius aestivus Brundin, 1947. 1. Hypopygium, dorsal view. 2. Hypopygium, ventral view.