Aloninae Dybowski & Grochowski, 1894 sensu Frey, 1967

Subfamily Aloninae Dybowski & Grochowski, 1894 sensu Frey, 1967

Alona kotovi Sinev, 2012 View in CoL . Rare in studied material, found in November only in Yingzhow Lake (N20). A. kotovi View in CoL inhabits water bodies of various types with a muddy bottom ( Sinev 2012). The species is recorded in the Indo-Malaysian Region, South Korea, Hainan, Hunan, Hubei and Yunnan Provinces of China (Sinev, 2016; Sinev et al. 2020; Dadykin et al. 2023). Earlier records of Alona View in CoL s. str. from East China ( Ji et al. 2015) were attributed to

Palearctic A. quadrangularis (O.F. Müller, 1776) View in CoL , but all the populations from Central China probably belong to A. kotovi View in CoL .

Camptocercus uncinatus Smirnov, 1971 View in CoL . A littoral phytophilous species, present in littoral zone of lakes, frequent in November, less numerous in January and March, predominantly occurred in lakes. C. uncinatus View in CoL is distributed in southern Europe, Israel, Iraq, Egypt, Ethiopia, Rift Valley of Africa, South-West and East Siberia and Korea ( Sinev 2014), and North-East Thailand ( Tiang-Nga et al. 2020). In China, the species was recorded in Hainan, Hunan, Hubei and Yunnan Provinces ( Dadykin et al. 2023, Sinev et al. 2020). The most frequently reported species of Camptocercus View in CoL in China is C. australis Sars, 1896 View in CoL ( Ji et al. 2015) but this species is confined to Australia (Sinev 2015), and all these records most probably belong to C. uncinatus View in CoL as well.

Coronatella ( Coronatella) jejuana Sinev, Lee & Kotov, 2022 ( Fig. 2D–H View FIGURE2 ). Littoral species, associated with vegetation, it is rather rare, found in all seasons in Dazong Lake, in November in Zhaoyang lake, and in March in Hushan lake (M14, M15). The first record for China, so far it was known only from terra typica, Jeju Island, South Korea ( Sinev et al. 2022). The species can be easily confused with C. (C.) rectangula View in CoL , common in Central China.

Female. Morphology of studied populations agrees well with that from initial description of the species. Chinese populations have a rather low body ( Fig. 2D View FIGURE2 ), antenna with extremely long spines ( Fig. 2F View FIGURE2 ), setae of inner distal lobe of thoracic limb I of a characteristic morphology ( Fig. 2G View FIGURE2 ) and postabdomen of a characteristic shape ( Fig. 2H View FIGURE2 ) armed with groups of short elementary denticles, The only difference between Jeju and Chinese populations concerns the morphology of setulae on the postero-ventral angle of valves, in Chinese populations they are differentiated, forming several groups ( Fig. 2E View FIGURE2 ), while in populations from Jeju they are completely uniform ( Sinev et al. 2022).

Male. The length of a single studied specimen was 0.31 mm, height was 0.17 mm. Body ( Fig. 2I View FIGURE2 ) low oval, with maximum height before midline, lower than in female, height/length ratio about 0.54. Ocellus and eye larger than in female.

Postabdomen ( Fig. 2J View FIGURE2 ) short, with almost parallel margins in anal portion, narrowing distally in postanal portion, dorso-distal angle not defined. Ventro-distal angle well-defined, obtuse. Sperm duct openings located ventrally almost at the end of postabdomen. Preanal angle is well-defined, postanal angle is not defined. Distal part of postabdomen 1.5 times longer than proximal part. The preanal, anal portion is 1.5 times longer than the postanal one. Clusters of short setulae in place of marginal denticles, lateral fascicles of setulae wider and located more close to each other than in female. Postabdominal claw shorter than that of females, with four-five strong spines on the inner side. Basal spine long and thin, about 0.3–0.4 length of claw.

Antennule ( Fig. 2K View FIGURE2 ) thicker than in female, with 10 terminal and 2 lateral aesthetascs. Lateral aestetascs of unequal length, about 2/3 and 1/2 length of the antennule. Male seta arising at 2/3 length from tip, about 1/3 of antennule length. A single cluster of long setulae is located on the anterior face of the antenna.

Thoracic limb I ( Fig. 2L–N View FIGURE2 ) with a short U-shaped copulatory hook 25 times shorter than limb itself. Copulatory brush present, copulatory brush seta short. Ventral face of limb below them with double row of numerous short thick setulae. Inner distal lobe without seta 1; setae 2 and 3 much shorter and thinner than in female, armed with moderately thick setulae; male seta curved, a little longer or as long as seta 2.

Males of C. ( C.) jejuana differ from males of C. ( C.) rectangula (see descriptions in Sinev 2020, Sinev et al. 2020) in shape of postabdomen, in unequal in length lateral aestetascs of antenna, and in IDL seta 3 without strong spine. C. ( C.) jejuana can be easily confused with C. ( C.) rectangula , so it is possible that this species is widely distributed in Central and North China.

Coronatella rectangula (Sars, 1862) . Common littoral phytophilous species, abundant in all seasons. Few males and ephippial females were present in November only. Predominantly Palearctic species, distributed from Spain to Far East of Russia, common in China. In East Asia, the species penetrates south up to Peninsular Malaysia and Borneo, but the Southeast Asian populations differ slightly from those of the Palearctic in that they have narrower postabdomen, probably presenting species-complex (Sinev et al. 2015). Common in China ( Ji et al. 2015).

Coronatella trachistriata (Chen, Zhang & Liu, 1994) . The species was found in March in open water plankton sample from Qili Lake, sample was taken during strong wind, water was very turbid. The species was not present in samples from macrophytes or open littoral, so we presume it inhabit bottom sediments. Morphology of found specimens was studied in details by Sinev et al. (2024). This rare species was previously known from Jiangxi, Shandong, and Anhui Provinces of China ( Ji et al, 2015), Hainan Island (Sinev et al. 2015), and from Far East of Russia (Kotov et al. 2011; Garibian et al. 2019).

Euryalona orientalis (Daday, 1898) View in CoL . Littoral phytophilous species, rare in studied material, several parthenogenetic females ( Fig. 3A–B View FIGURE 3 ) and a single ephippial female ( Fig. 3C View FIGURE 3 ) were found in November in Dazong Lake (N3). Presumably a pantropical species, common in Indo-Malaysian region ( Rajapaksa & Fernando, 1986; Sinev, 2016) and South China ( Ji et al, 2015). This is the most northern occurrence of the species in East Asia, it was previously found in Wuhan area, Hubei province ( Dadykin et al. 2023).

Flavalona costata (Sars, 1862) . Common littoral phytophilous species, abundant in all seasons. Few males and ephippial females were present in November and January, but most populations were always composed of parthenogenetic females. Palearctic species, in East Asia penetrating south to Hainan Island and North-East Thailand (Sinev 2016). Common in China ( Ji et al. 2015).

Graptoleberis testudinaria (Fischer, 1851) View in CoL . The species is associated with submerged macrophytes, found in November and January in Weishan lake among macrophytes, and in January in Biamu lake (J16). The species is described from North Europe, recorded worldwide, probably forming a species complex. In Eurasia, species is common in cold and temperate regions, rather rare in tropics ( Korovchinsky et al. 2021b). Common in China ( Ji et al. 2015).

Kurzia latissima (Kurz, 1875) View in CoL . Found in November in Gaotang Lake (N21) and in a ditch near Gaotang lake (N22). Predominantly Palaearctic species, characteristic for small and temporary waterbodies ( Korovchinsky et al. 2021b). Uncommon in China ( Ji et al. 2015)

Monospilus dispar Sars, 1862 View in CoL . Few specimens were found in November in open littoral sample from Luoma Lake. M. dispar View in CoL is associated with sandy littoral. The species is recorded worldwide, and probably represents a species complex. In Eurasia, M. dispar View in CoL is common in cold and temperate regions, rather rare in tropics ( Korovchinsky et al. 2021b).

Nicsmirnovius eximius (Kiser, 1948) View in CoL . A rheophilous species, commonly encountered in rivers and streams, also occurring in littoral zone of large lakes. Found in November only, in open or sparsely vegetated littoral of the lakes, no males or ephippial females were present. N. eximius View in CoL is predominantly a tropical species, common in South-East Asia, extending northward to Central China ( Ji et al. 2015; Dadykin et al. 2023).

Nedorhynchotalona chiangi Kotov & Sinev, 2011 . The species was found in March in open water plankton sample from Qili Lake, sample was taken during strong wind, water was very turbid. Species was not present in samples from macrophytes or open littoral, so we presume it inhabit bottom sediments. Morphology of found specimens was studied in details by Sinev et al. (2024). Species is distributed from Amur basin in Russia to South China ( Ji et al, 2015).

Ovalona cambouei (Guerne & Richard, 1893) . Littoral species, rare in studied material, parthenogenetic females were found in November in Dazong lake. O. cambouei is widely distributed in Paleotropics, common in Central and South China ( Ji et al. 2015).

Oxyurella tenuicaudis (Sars, 1862) View in CoL . Littoral phytophilous species, rare in studied material, found in November in a pond near Tou Lake (N8), Yingzhow lake (N20) and Gaotang lake (N21). Predominantly Palearctic species ( Korovchinsky et al. 2021b), common in North and East China ( Ji et al. 2015).

Prendalona guttata (Sars, 1862) . Littoral phytophilous species, present in littoral samples in all seasons, never abundant, only parthenogenetic females were found. Species presumed to be cosmopolitan, probably a species-complex, in Eurasia, common in cold and temperate regions, rare in tropics ( Korovchinsky et al. 2021b). Common in China ( Ji et al. 2015).