Isoperla mongolica ZHILTZOVA, 1972

Zwick, P & Surenkhorloo, P, 2005, The Mongolian Species Of Isoperlinae (Plecoptera: Perlodidae), Acta Zoologica Academiae Scientiarum Hungaricae 51 (3), pp. 253-276 : 270-272

Isoperla mongolica ZHILTZOVA, 1972

( Fig. 10 )

Isoperla mongolica ZHILTZOVA, 1972 , Nacekomye Mongol. 1: 132, figs 9–12.

Material studied. Cleared tip of paratype male abdomen, in glycerol: “1692. Mongolia, 15 km from Ulan Bator, Tuul River, near Gatsurt, 16. VII.[19]67, leg. Kherzner ". 1 m with partly everted penis, 3 ff ff: “7.; Mongolia, Ovorkhangai aimak, Sumiin and Chuluut River near bridge, 29. VI.[19]57, M. Kozlov ” (labels in Cyrillic script; all from coll. ZHILTZOVA. Zool. Mus. St. Petersburg) .

Additional material. MONGOLIA: Chovd aimak: 3 km N Somon Uenč, 1450m, Uenč gol, 2.–3.VII.1966, 8 mm, 18 ff [KASZAB 614, 618, 622]; ca 35 km N Somon Uenč, Mongol Altaj Gebirge, 1750m, kl. Nebenbach des Uenč gol, 8.VII.1966, 1 mm, 6 ff [KASZAB 646]; ca 44 km N Somon Uenč, Mongol Altaj Gebirge, 1780m, Uenč gol, 8.VII.1966, 21 mm, 4 ff [KASZAB 647]; Somon Uenč , ca 2 km N vom Dorf, 1450m, Uenč gol, 7.VII.1966, 2 ff [KASZAB 643] . Chövsgöl aimak: 8 km N Somon Alag-erdene, 1600m, Egijn gol, 17.VII.1968, 1 m [KASZAB 1121] ; 8 km N von Somon Burenchaan , 1450m, Delger mörön, 20. VI .1968, 2 mm, 15 ff [KASZAB 990]; zw. Somon Cecerleg und Somon Bajan-ul , 65 km W Cecerleg , 1700m, 22. VI .1968, 1 m [KASZAB 1002]. KAZACHSTAN, Ust Kamenogorsk [49°58’N, 82°36’E], leg. & det. V . DEVYATKOV, 19 mm,14 ff (in coll. ZWICK)

rior egg pole with collar and anchor

The present material was recognized by the large ventral lobe on male sternite 8th and the apically slightly spinulose paraprocts. The identification was confirmed by comparison with a male paratype and additional material identified by L. A. ZHILTZOVA. We provide a brief general description and add details of the previuously undescribed penis, vagina, and egg.

Size. Fore wing length, mm 8.9–9.5 mm, ff 10.8–12.8 mm.

Colour pattern. General colour dull ochre to light brown, with pale marks. Head infuscated from front of clypeus to behind ocelli; a rhomboid pale spot remains between ocelli and there is often a small pale mark just in front of the anterior ocellus ( Fig. 10a ). Posterior corners of head and scape also slightly infuscate. Pronotum infuscated, with wide pale middle band and narrow pale lateral edges; muscle attachment scars darker than rest. Mesonotum pale to light yellow in front of and between wings, remainder brown. Metanotum brown, except paler part laterally, in front of wings. Ventral thoracic sclerites light brown. Abdomen dorsally ochre, ventrally lighter, yellowish. Antennae light brown, a little darker than ochre palpi, legs, and cerci.

Structure. A typical Isoperla species. R without fork, single long fork of Rs, branches of M usually forked, with long stem. Legs without large setae. Cerci with elongate segments, each ventrodistally with a single erect seta, rarely 2 setae.

Male. Base of abdomen dorsally with pale paramedian bands diminishing from I-III, sometimes IV, and eventually vanishing; posterior segments unicolorous, a little darker than in female. Tergites IX and X medially a little extended, darker than rest, with enhanced pilosity. Sternite VIII: a dark semicircular line demilits a deep notch from which rises the broad, medially constricted peduncle of the wide, rounded and slightly pilose brown ventral lobe. Sternite IX large, bulging over bases of paraprocts. Tips of paraprocts curving forward over distal edge of tergite X, rounded, anteriorly rough owing to presence of several sensilla basiconica.

Penis observed only in contracted ( Fig. 10b ) and partly everted condition (see ZHILTZOVA 1972, her fig. 11). Penis consisting of several arched folds of rather stiff integument ( Figs 10c 1-c 3 ) covered uniformly with minute teeth, each with large guttiform base ( Fig. 10c 1 , inset). It appears that the wide funnel-shaped part with the conical median piece stands at the tip of the everted organ.

Female. Subgenital plate only insignificantly projecting, no characteristic form or pigmentation. Vagina is not distinctive, membraneous, without sclerotized elements.

Egg ( Figs 10d, e ). 185 µm wide, 272 µm long, including 8.5 µm for collar. Oval, posterior (= opercular) pole regularly rounded, wide, sides of egg near collor less arched, narrowing a little towards anterior pole with collar. Chorion about 4 µm thick, uniformly covered with deep, large punctures, their arrangement in polygonal fields indistinct. No opercular suture. Collar 34 µm wide at recurved wavy distal flange, with a few longitudinal crests, base deeply embedded. Anchor fungiform.

Diagnostic characters and affinities. The large ventral lobe on male sternite VIII in combination with the apically spinulose paraprocts permits immediate recognition of males. For female identification, see the key. The relations with other species are doubtful.

Figures

Fig. 10. Isoperla mongolica ZHILTZOVA. a = adult head and prothorax, b = lateral view of male abdominal tip with folded penis in natural position; arrows and letters identify directions of views shown in Figs c1–3. c1-c3 = folded penis in three different views (inset C1 enlarged); compare Fig. 10b for directions, d = egg, lateral view.e = combined lateral views and optical sections through ante-

Fig. 1. Isoperla lunigera (KLAPÁLEK). a = head and pronotum, b = female sternite 8, c = dissected sternites 8 and 9 in dorsal view, showing genital pouch, receptacle, andaccessory glands; d = detail of genital pouch and receptacle, e = egg, f = detail of collar indicating chorion thickness and inner parts

Fig. 3. Isoperla altaica Šámal. a = head and prothorax, b, c = male abdominal tip in ventral and dorsal views, respectively; d, e = penis sclerite in lateral and caudal views, respectively, f = spicules on penial membrane next to large sclerite, g = male with everted penis, lateral view, h = female abdomi-