Isoperla ornata Zhiltzova, 1980

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 : 24-27

Isoperla ornata Zhiltzova, 1980

( Figs. 61–67)

Description. The nymph of this species was previously described by Teslenko and Zhiltzova (1997), associated by rearing nymphs from the Tumangan River. Length of mature male nymph 10.0– 12.3 mm, female 10.9–13.0 mm; cerci of male nymph 4.2–4.7 mm, female 5.0– 5.2 mm. Antennae, legs, cerci yellowish; body yellow, with distinct brown pigment patterns, body covered by dark clothing hairs.

Head with complete spinule row on occiput; pale brown M­shaped mask across anterior ocellus with a paler M­line anteriorly ( Fig. 61); two small, sublateral, pale spots within mask; interocellar area pale, enclosed by darker pigment. Occiput mostly dark with sublateral pair of rounded pale spots and one medial pale triangle. Labrum with contrasting longitudinal pigment lines, pale medially and laterally. Lacinia bidentate, triangular ( Fig. 62 ), five to six heavy setae about subapical tooth, basal third with a row of short hairs on inner, slightly concave margin; galea not reaching base of subapical tooth. Mandible with six unserrated teeth and two rows of setae ( Fig. 63 ).

Thorax. Pronotum ( Fig. 61) pale mesally with a faint, narrow, medial darker stripe, outer parts of lateral fields brown, lateral margins pale, anterior and posterior margins darkened; a complete marginal row of short setae present with occasional long setae at anterior and posterior corners. Meso­ and metanota ( Fig. 61) mostly pale medially, with faint, median dark stripe continuous from pronotum; wider, longitudinal pigment stripes present at wing pad bases, lateral margins and tips pale; lateral margins of wing pads with stout setae. Legs pale ( Fig. 64 ), unicolorous, with fine recumbent brown clothing hairs. Tarsi, tibiae, and femora fringed with colorless, silky hairs along posterior margins.

Abdominal terga with alternating dark and pale longitudinal bands ( Fig. 61), mesal band dark. Abdominal terga with numerous short intercalary bristles; posterior tergal margins with fringe of thin setae, some of them longer than others. Apical third of cerci ( Fig. 65–67 ) with dorsal fringe of long, silky hairs; apical segments with apical setal whorl having one dorsal and one ventral setae longer than others.

Material examined: Russia. Primorsky Region, Tumangan R., 16.V 1990, (reared), V. Teslenko, 14 nymphs.

Distribution. Russia: Primorsky Region; China; North Korea.

Figures

FIGURES 62 – 67. Isoperla ornata (redrawn from Teslenko & Zhiltzova 1997): 62. Right maxilla, ventral. 63. Right mandible, ventral. 64. Right leg, dorsal. 65 – 67. Basal, middle, and apical sections of right cercus, lateral. Scale (mm): 62, 63 = 0.25; 64 = 1.0; 65 – 67 = 0.5.