Chydorinae Dybowski & Grochowski, 1894

Subfamily Chydorinae Dybowski & Grochowski, 1894

Alonella excisa (Fischer, 1854) View in CoL . Littoral phytophilous species, rare in the studied material, few specimens were found in November in Yingzhow Lake, in January in Dazong Lake, and in March in lakes Dazong, Hvshan and Qili. Species group is presumably cosmopolitan ( Korovchinsky et al. 2021b), common in temperate and subtropical regions, rare in tropics. Common in China ( Ji et al. 2015).

Chydorus cf. biovatus Frey 1985 View in CoL (fig. 3 D–G). Eurybiotic littoral species, sometimes encountered in pelagic zone. Most abundant littoral species in all seasons, frequently dominant in littoral samples. Single male was found in January in Biamu lake (J16), ephippial females were present in samples from both January and March. Ch. cf. biovatus View in CoL belongs to Chydorus sphaericus View in CoL species complex. Species of the sphaericus View in CoL -complex in Eurasia have identical morphology of parthenogenetic females, but might be distinguished by male and ephippial female morphology ( Belyaeva & Taylor 2009; Klimovsky & Kotov, 2015; Kotov et al. 2016). Males of Chydorus cf. biovatus View in CoL were found by Dadykin et al. (2023) in Hunan Province in spring. Male from our material ( Fig. 3D View FIGURE 3 ) had a rounded rostrum (Fig, 3E), labrum with elongate acute apex ( Fig. 3F View FIGURE 3 ) and postabdomen with weakly developed preanal angle and claw without basal spine ( Fig. 3G View FIGURE 3 ) typical of the species. Ch. biovatus View in CoL s. str. is widely distributed in Nearctic, but populations with a similar morphology were reported from Yakutia and Kamchatka ( Korovchinsky et al. 2021b). Our data suggest that all Chydorus cf. sphaericus View in CoL populations from Central China belong to C. cf. biovatus View in CoL .

Disparalona ( Mixopleuroxus) chappuisi Brehm, 1934 . Littoral substrate-associated species, abundant in studied material in both November and January. Few males and ephippial females were found in November, but only gamogenetic speciemens were present in January. Morphology of male of studied population ( Fig. 3H–K View FIGURE 3 ) is similar to that reported for populations from South Korea (see Neretina et al. 2018). The species is known from Africa and tropical Asia, in East Asia penetrating north to Far East of Russia ( Neretina et al. 2018). Populations of D. chappuisi from East and South-East Asia, including those from China (see Ji et al. 2015; Sinev et al. 2015) were recorded as D. hamata Birge, 1879 View in CoL , but recent revision clarified its status ( Neretina et al. 2018).

Disparalona ( Disparalona) ikarus Kotov & Sinev, 2011 . Littoral species, encountered in both open littoral and vegetated area of lakes during all seasons, never numerous in studied samples. No gamogenetic speciemens were found. Species is distributed from Amur River basin to Hainan Island and North-East Thailand ( Korovchinsky et al. 2021a). In continental China, the species was recorded from Yunnan, Hunan and Hubei Provinces ( Sinev et al. 2020; Dadykin et al. 2023). Earlier Disparalona View in CoL s. str. records from China were attributed to D. ( D). rostrata (Koch, 1841) ( Ji et al. 2015), but actually all populations from China probably belong to D. ( D). ikarus .

Pleuroxus ( Picripleuroxus) laevis (Sars, 1862) . Littoral phytophilous species, present in littoral samples in all seasons, never numerous. No gamogenetic specimens were found. Predominantly a Palearctic species, common in temperate regions of Eurasia, rare in Paleotropics; in East Asia penetrates south to Malaysian peninsula ( Korovchinsky et al. 2021b).

Pleuroxus ( Picripleuroxus) quasidenticulatus (Smirnov, 1996) . Species associated with abundant macrophytes in the littoral zone of most lakes. Few males and ephippial females were found in November, but only gamogenetic specimens were present in January and March. Distributed in Central, East and South-East Asia and Australia ( Korovchinsky et al., 2021b). In China, the species was recorded predominantly as P. assimilis Brady, 1906 View in CoL ( Sinev & Sanoamuang 2013; Ji et al. 2015).

Pleuroxus (Pleuroxus) aduncus (Jurine, 1820) View in CoL . Littoral species, associated with vegetation, found only in March in Weishan lake and Hushan lake (M15); quite numerous in both lakes, only parthenogentic females were present. Palearctic species ( Korovchinsky et al. 2021b). Common in China, but some records, especially from South part, can be unreliable ( Ji et al., 2015).

Pseudochydorus bopingi Sinev, Garibian & Gu, 2016 . Littoral species, feeding on microcrustacean remains, occurs mostly in the littoral samples with high density of other Cladocera . The species was found in November, in Dazong lake and in ponds and channels near Zhaoyang lake (N12–14), only parthenogenetic females were present. A single juvenile specimen was found in March in Gaoyou lake (M2). The species is known from Central and South China, Thailand and Vietnam ( Dadykin et al., 2023). Earlier Pseudochydorus View in CoL records from China were attributed to P. globosus ( Ji et al. 2015) View in CoL , but all populations from East China probably belong to P. bopingi .