Isoperla lunigera Klapálek 1923

Teslenko, Valentina A. & Zhiltzova, Lidiya A., 2006, Nymphs of the genus Isoperla Banks (Plecoptera, Perlodidae) from the Eastern Palaearctic Region, Zootaxa 1130, pp. 1-33 : 16-17

Isoperla lunigera Klapálek 1923

( Figs. 35–41)

Description. Association was established by rearing nymphs from the Zeya River. Length of mature male nymph 8.5–9.3 mm, female 9.6–11.2 mm; cerci of male nymph 5.2–5.5 mm; female 5.2 –5.5 mm. General body color pale with grayish­brown pattern on the head, thorax, and abdominal terga ( Fig. 35). Antennae, legs, cerci, and ventral side pale. Clothing hairs thin and numerous.

Head with continuous occipital spinule row; U­shaped dark spot open anteriorly forward of anterior ocellus, lateral margins of this spot do not reach antennal bases ( Fig. 35); on anterior frontoclypeus two small, brownish transverse spots; labrum brown; interocellar area with small, triangular, light spot, darkened basally; occiput pale with transverse darkened band between compound eyes interrupted medially; lateral margins of frontoclypeus to antennal bases pale. Lacinia bidentate ( Fig. 36 ), triangular, inner margin slightly rounded basally, seven or eight stout setae and two rows of short thin setae below apical tooth. Galea short, claw­shaped, its tip not reaching the base of the subapical tooth. Mandible ( Fig. 37 ) as in other species.

Thorax. Pronotum ( Fig. 35) transverse­oval, fringed with short setae, occasional long setae interspersed at posterior margin; medial area pale, surrounded by darker circular area, lateral margins pale, anterior and poster margins darkened. Meso­ and metanotum ( Fig.35) with large pale areas medially; base of the wing pads slightly brownish with a few short brown setae; lateral margins and wing pad tips pale. Legs ( Fig. 38 ) pale, with dense fringe of silky swimming hairs along outer margins of tarsi, femora, and tibiae.

Abdominal terga ( Fig. 35) with two rows of mesal, rounded, pale spots extending through Ab8, these divided by thin median brown stripe, Ab9–10 mostly pale except anterior margin. Tergal margins pale, posterior margins with fringe of pale setae. Cerci ( Fig. 39–41 ) pale, apical half densely packed with dorsal, silky fringe hairs, length of hairs not exceeding length of the corresponding segments; apical whorl in apical third with short setae and one slightly longer ventral seta.

Material examined: Russia. Amur Region, Zeya R., near Set. Krasnoyarovo, 25.VI 2004, V. Teslenko, 2 nymphs; Bolshaya Ussurka R., 8.VI 2004, V. Teslenko, 9 nymphs; Ussuri R., 23.V 2003, E. Barabanshichkov, 1 nymph.

Distribution. Russia: Altai Mnts., Sayan Mnts., Transbaikal Region, Amur Region, Khabarovsky, Primorsky Regions; Mongolia.

Figures

FIGURES 36 – 41. Isoperla lunigera: 36. Right maxilla, ventral. 37. Right mandible, ventral. 38. Right leg, dorsal. 39 – 41. Basal, medial, and apical sections of right cercus, lateral. Scale (mm): 38 = 0.51 mm; 36, 37, 39 – 41 = 0.4.