Isoperla maculata Zhiltzova, 1977

Teslenko, Valentina A., 2025, Eggs of twelve Siberian and Far Eastern Isoperlinae (Plecoptera: Perlodidae), Zootaxa 5642 (3), pp. 201-224 : 212

Isoperla maculata Zhiltzova, 1977

Figs. 48–55

Material examined. Russia, Far East, Khabarovsk Krai: 1♂, Anyuisky National Park, Bira Channel , Amur R. basin, 19.06.2018, coll. N. Yavorskaya ; 9♂ 11♀, Anyuisky National Park, Anyui River, Nilo Chanell , at light, Amur R. basin, 23.07.2018, coll. Ev. Makarchenko ; Primorsky Krai: 1♂, Barabashevka River , above the fish factory, 24.06.2021, coll. T. Tiunova ; 1♂ 4♀, Ryazanovka River , cordon, 9.06.1998, coll. V. Lyubarets ; 7♂ 9♀, Barabashevka River , near the fish factory, 9.06.2003, coll. V. Teslenko ; 5♂ 4♀, Artemovka River near the Mnogoudobnoye settlement, 14.07.2002, coll. V. Lyubarets ; 1♂ 2♀, Shumnaya River, Shumny settlement, Ussuri R. basin, Amur R. basin, 29.06.2017, coll. V. Lyubarets ; 2♀, Lazovka River, Lazo settlement, Partizanskaya R. basin, 22.08.2006, coll. Shokhrin.

Egg. The egg of I. maculata is described here for the first time. Shape oblong, with a wide diameter closer to the posterior pole; a cross-shaped ridge near the equator dividing the anterior and posterior poles; posterior pole triangular in cross-section with an indistinct cross-shaped ridge on each side; anterior pole quadrangular in cross-section with four longitudinal ridges and apex slightly concave ( Figs. 48‒51 ). Length 269 µm, maximum width nearer to posterior pole 165 µm (n=1). Collar well developed, elevated with irregular and raised longitudinal ridges, rim widely flanged, wavy apically ( Figs. 49–50, 54 ). Anchor mushroom-shaped, globular bodies concentrated into groups of 2–5, located mainly in a peripheral area along the anchor edge and top of the anchor deeply embedded ( Figs. 48, 53 ). Chorion covered with hexagonal FCIs with thickened, elevated, and raised ridges and numerous (12–20) deep pits ( Figs. 49, 55 ). Micropyles small, poorly distinguishable due to their similar size to the pits in hexagonal FCIs and arranged singularly in a row on follicle cell ridges near anterior ⅓ of the egg ( Fig. 55 ). Orifices round and located on raised horizontal, tunnel-shaped relatively long sperm guides laterally; sperm guides weakly visible and unassociated with FCI rossetes ( Figs. 52, 55 ). Eclosion line absent.

Distribution. East Asian species with limited distribution in the south of the Russian Far East, including the Jewish Autonomous Region, Khabarovsk Krai, and Primorsky Krai.

Figures

FIGURES 48–55. Isoperla maculata Zhiltzova, 1977. Russia, Far East, Khabarovsk Krai,Anyuisky National Park,Anyui River, Nilo Chanell, Amur R. basin. Egg. 48. Uncleaned, habitus with anchor, extrachorion layer with mushroom bodies over FCIs, lateral. 49. Cleaned, habitus with collar lateral. 50. Posterior pole, collar rim view from above. 51. Anterior pole with concave apex. 52. Orifice round, lateral. 53. Anchor with globular bodies, lateral. 54. Collar with irregular and raised longitudinal ridges, lateral. 55. Micropyle row on raised, tunnel-shaped, and relatively long and weakly visible sperm guides; chorion structure, and orifices, lateral.