Tokunagaia parexcellens

Author: Tuiskunen, 1986

Diagnosis (Material in coll. ZMBN; in part after Halvorsen and Saether, 1987a - in italics)
Exuviae 2.6-4.0mm long (m=3.5mm, n=8).
Colour: Dark exuviae; brown, abdominal segments with a broad posterior transverse dark brown band, in which the posterior adhesion marks show up clearly because of their paler colouring.
Cephalothorax: Frontal setae and warts absent. Antennal sheath with weak pearl row distal to pedicel, pearls stronger on inner margin. Ocular field with 1 postorbital. Thoracic horn absent. Median antepronotal setae 1,2: 75-115; 60-110µm long (n=5); precorneal setae 1-3: 75-110; 75-135; 38-93µm long (n=5); dorsocentral setae 1-4: 55-80; 20-60; 43-65; 35-45µm long (n=5). Wing sheaths without pearl row.
Abdomen: Segments II-VIII dorsally nearly covered with small points except for the adhesion marks. Hook rows on tergites continuous; hooks III 30-50, IV 35-53, V 31-52 (n=7). Tergite III with the median points distinctly smaller and less dense than those around, anterior row shagreen very limited, restricted to the margin of the point patch (050b.jpg). Posterior transverse band of tergite III of distinctly enlarged points about 5 points deep; longest points about 5µm long, about twice as long as broad at base, i.e. distinctly elongate (050b.jpg). Posterior teeth III 11-18, IV 11-20µm long (n=5). Pedes spurii A and B absent. Longest lateral seta VIII 78-120µm long (n=9).
Anal segment: Anal lobe ratio 1.5-1.6 (n=3). Anal lobes without fringe. Anal macrosetae 0.6-0.8x length of the anal lobe (n=4). Male genital sheaths extend only half-way along the anal macrosetae (050c.jpg).

Species keys out at Page 699: Orthocladiinae 111 Tokunagaia of the Text Key.

(For more information see module IdentifyIt – file: Orthocladiinae).

Ecological notes
Barren fast-flowing streams and rivers in northern Fennoscandia, emerging in late summer.