Kaszabia nigricauda

Kaszabia nigricauda (Navás, 1923) Figs. 90–98 Material examined: Russia, Far East, Amurskaya Oblast: 3♂ 5♀, Norsky Nature Reserve, Nora River, cordon near Berezovoye Lake, Selemdzha-Zeya-Amur R. basins, 16.06.2004, coll. V. Teslenko; 5♂ 6♀, Tom River, under the bridge, Amur R. basin, 13.06.2004, coll. V. Teslenko; 1♀, Deya River, Bureya R. basin, Amur R. basin, 4.07.2014, coll. V. Teslenko; 3♂ 10♀, Dzhilimkur River, Zeya R. basin, Amur R. basin, high way bridge, 8.07.2013, coll. V. Teslenko; 3♀, Dikan River, under high way bridge, Bureya R. basin, Amur R. basin, 28.06.2014, coll. V. Teslenko; Khabarovsk Krai: 2♂ 3♀, Bolshoy In River, Tunguska R. basin, Amur R. basin, 11.06.2004, coll. V. Teslenko; 5♂ 7♀, Khekhtsirsky Nature Reserve, Beshenaya River, Amur R. basin, 10.06.2018, coll. N. Yavorskaya; Primorsky Krai: 2♂ 4♀, Avan River, Ussuri R. basin, Amur R. basin, 23.06.1998, coll. V. Teslenko. Egg. Pear-shaped, triangular cross-section near the posterior ½; anterior ½ quadrangular with distinct cross-shaped ridges near the equator dividing anterior and posterior poles; anterior pole concave (Figs. 90–91, 94–95). Length 273‒298 µm, width 175‒214 µm (n=5), chorion thickness 2.8 µm. Collar relatively high with irregular longitudinal ridges, base embedded and covered with pits extending to the rim; the rim is narrow, flanged, and wavy (Figs. 92–93, 95). Anchor small, biscuit-shaped, and flat, covering only the rim; relatively large, single, globular bodies scattered over the entire anchor surface (Figs. 92–93); chorionic surface uniformly and densely covered with numerous small punctations; hexagonal FCIs not visible (Figs. 97–98). Eclosion line absent. Micropyles are scattered in groups of 3 or 4 in the subequatorial region (Figs. 90–91); orifices slightly elongated and sperm guides poorly visible (Fig. 96). Distribution. East Palaearctic species with a broad geographical distribution in Russia from Siberia (Altai, Sayan Mountains, Baikal Lake Basin, Transbaikalia) to the Far East (Amurskaya Oblast, Jewish Autonomous Region, Khabarovsk Krai, Primorsky Krai). Kazakhstan. Mongolia. China (Huo & Du 2020). Remarks. The status of K. nigricauda was discussed in some detail in Huo & Du 2020. Our studies did not reveal any clear differences in the morphological features of Isoperla and Kaszabia eggs, especially since there is overlap with characteristics. It should also be noted that a comparison of the eggs of Kaszabia and Isoperla species with abdominal processes on male terga could not be carried out in full due to the lack of egg descriptions or due to the lack of SEM illustrations. The eggs of K. nigricauda are very similar in shape and chorion structure to the eggs of the Nearctic species Isoperla lenati Szczytko & Kondratieff, 2015. The main difference is the size of the collar; the collar of the K. nigricauda is significantly higher than that of the I. lenati. According to our research, we can conclude that the eggs of Kaszabia are pear-shaped, the anchor is biscuit-shaped, the collar is slightly higher than in the examined Isoperla species, hexagonal follicle cell impressions are not visible, and the chorion is covered uniformly and densely with numerous small punctations.