Claassenia brachyptera Brinck, 1954

Claassenia brachyptera Brinck, 1954 View in CoL

Figs. 19−29 View FIGURES 19–23 View FIGURES 24–29

Material examined. Russia, Far East, Amurskaya Oblast : 1♀, Zeya River , Amur River basin, Zagan village , 02.08.2005, coll. T. Tiunova; 1♀, Zeya River, Sokhatino village , 19.07.2006, coll. T. Tiunova; 9♂, Zeya River, 1 km above the bridge near the Krasnoyarovo village , Amur River basin, 20.08.2004, coll. V. Teslenko; 3♂, 1♀, Bureya River , Amur River basin, 500 m below the Kulikovka village , 17.08.2003, coll. T. Tiunova; Primorsky Krai, 9♂, 12♀, Ussuri River , Amur River basin, below the Kamenka village , 07.05.1993, coll. V. Teslenko; 2♂, 1♀, the Bolshaya Ussurka River , Amur River basin, a channel below the Zvenigorodka village , 20.07.1996, coll. T. Tiunova.

Egg. Spindle-shaped ( Figs. 19−20 View FIGURES 19–23 , 24−25 View FIGURES 24–29 ), with a total length of 472−485 μm and an equatorial width of 370−380 μm (n=4). Collar is low, button-like, and shoulder-wide ( Figs. 20–21 View FIGURES 19–23 ). Anchor is wide and short, cap-shaped; the anchor surface is studded with mushroom bodies distributed irregularly and densely towards the peripheral anchor margin ( Fig. 19 View FIGURES 19–23 ). On an uncleaned egg, the anchor is covered with a sticky and gummy-like extrachorionic layer that makes it difficult to separate individual eggs ( Figs. 28–29 View FIGURES 24–29 ). The anchor top is sunken and reveals several additional, sophisticated attachment structures, such as long papillary projections ( Fig. 24 View FIGURES 24–29 ). The chorion surface is smooth or covered with weak hexagonal FCI’s; the pits are also weak and barely observable; the anterior pole is covered with more prominent follicle cell impressions ( Figs. 19−20, 22−23 View FIGURES 19–23 ); and the shoulder surrounding the collar is smooth without FCIs ( Fig. 21 View FIGURES 19–23 ). The extrachorionic layer of the uncleaned egg bears a single large (a few times larger than globular bodies on the anchor) mushroom body over each follicle cell impression on the anterior pole ( Figs. 25–26 View FIGURES 24–29 ). Micropylar row subequatorial ( Figs. 19−20, 22 View FIGURES 19–23 ), orifices set in small cup-like depressions with long, smooth, and open sperm guides extending from cup rims, canals slanted ( Figs. 22−23 View FIGURES 19–23 ), and an extrachorion layer around orifices covered with rosettes that look like flowers ( Figs. 24, 27 View FIGURES 24–29 ).

Comments. Eggs of other East Asian Claassenia Wu, 1934 species have not been studied sufficiently to compare them with those of C. brachypterа . However, the eggs of C. brachypterа have features similar to those of the Nearctic species C. sabulosa ( Banks, 1900) in habitus, size, structure of the chorion and micropyles, and the armature of the extrachorion layer on the anterior pole ( Stark & Sivec 2010). It should be noted that the range of C. brachyptera borders on another East Asian species, C. radiata Klapálek, 1916 . However, it is not possible to compare the eggs of these species since there is no egg description for C. radiata .

Distribution. East Palaearctic species is distributed widely in the temperate zone of the Asian mainland. This species occurs in Siberia ( south of the Krasnoyarskiy Krai, Sayan Mountains, and Yenisei River) and the Far East ( south of Yakutia, Amurskaya Oblast, Jewish Autonomous Oblast, Khabarovsk Krai, and Primorsky Krai).