Isoperla kozlovi Zhiltzova 1972

Isoperla kozlovi Zhiltzova, 1972 Figs. 35–40 Material examined. Russia, Far East, Amurskaya Oblast: 5♂ 15♀, Bureya River, Amur R. basin, Novobureysk settlement, 27.06.2013, coll. V. Teslenko; 16♂ 19♀, Bureya River, Novobureysk settlement, above Podoshva island, 28.06.2013, coll. V. Teslenko; Khabarovsk Krai: 10♂ 17♀, Bikin River, Amur R. basin, 300 m below the bridge, Vladivostok-Khabarovsk highway, 18.06.2000, coll. T. Tiunova; Prymorsky Krai: 1♂, Razdolnaya River, Zagorodnoye settlement, 08.06.2019, coll. E. Gorovaya. Egg. Rhombus-shaped, uniformly tapered toward the anterior and posterior poles, with a cross-shaped ridge along the anterior ⅓; posterior pole cross-section triangular, with three distinct longitudinal ridges; anterior pole quadrangular with four longitudinal ridges; anterior end of egg is convex (Figs. 35, 37, 38). Length 269–290 µm, width widest at ⅓ from the anterior pole of 173–177 µm, thickness 2.4 μm (n=2). Collar well developed, with short longitudinal ridges and a narrow flanged and slightly wavy rim; base covered with a mesh of empty cells of a smoothed triangular shape directed into interior of egg (Figs. 36–37, 39). Anchor mushroom-shaped, covered with small, globular bodies larger than other species (Fig. 36). Chorion near collar smooth, ranging downward from pentagonal to hexagonal FCIs with thick and elevated ridges; floors flat with numerous (ca. 19–29) punctations (Figs. 37‒38). Eclosion line absent. Micropylar row visible near the anterior ⅓ of egg (Fig. 35). Micropyles scattered in groups of 3 on FCI ridges and surrounded by rosettes of FCIs; orifices set in small oval cup-like depressions with short sperm guides (Fig. 40). Distribution. East Palaearctic species. Russia, West Siberia, West Altai, Sayan, Baikal Lake basin, Transbaikalia; Far East: Amurskaya Oblast, Jewish Autonomous Region, Khabarovsk Region, Primorsky Krai. East Kazakhstan (Devyatkov 2022). Mongolia. China, Northeast, including Changbai Mountain, Jilin Province (Chen et al. 2021). South Korea (Hwang & Muranyi 2020). Remarks. The original description of the egg indicates one of the diagnostic features—the shape of the collar. Collar with a few subdued meshes, edge simple, base smoothly bulging into interior of egg (Zwick & Surenkhorloo 2005).