Subfamily Aloninae

Alona cambouei de Guerne & Richard, 1898. Encountered in all types of vater bodies, more frequent in winter. Littoral species, associated with vegetation. For detailed description, see Sinev (2001), for description of the Indochina populations see Maiphae et al. (2008). Distributed in Mediterranean region, Africa, tropical Asia, frequently associated with rice fields. Recorded for China by Chen (1993) as Alona pulchella .

Alona costata Sars, 1962 . Encountered in reservoirs, ponds and once in a river; more frequent in spring. For description see Alonso (1996) and Sinev (1999). Morphology of studied specimens (Fig. 1 A–C) fully agree with the species description. Palearctic species, distributed in Europe, Siberia, Mongolia and Far East of Russia; south border of the area of distribution is unclear. A sibling-species, Alona cheni Sinev, 1999, was recorded in India, China, Thailand and Malaysia. These two species differ in morphology of lateral head pores; in A. cheni lateral head pores are longer, about distance between posterior and anterior main head pore, their pockets are demicircular. Presence of A. costata in Hainan is an unexpected result, presently Hainan is the southmost sure record of the species.

Alona guttata Sars, 1862 . Rare species; a single specimen was found in Manning reservoir (loc. 27) in winter. Littoral species, associated with vegetation. For detailed description see Alonso (1996) and Sinev & Silva-Briano (2012). Species presumed to be cosmopolitan, recent studies of Mexican populations revealed no significant differences from European specimens (Sinev & Silva-Briano 2012).

Alona kotovi Sinev, 2012 . Encountered in reservoirs, ponds and rivers once in both winter and spring. According to Sinev (2012), the species in Vietnam is associated with rivers, appearing on muddy or clay bottom; in Hainan it was also encountered in reservoirs and ponds, always on same substratum. For description see Sinev (2012). Species described from Vietnam and recently recorded from Korea (Jeong et al. 2014); according to Sinev (2012), its area of distribution probably includes India, South-East Asia and South China where it was confused with palearctic A. quadrangularis (O.F. Müller, 1776) . The first record for China, suggests that A. kotovi can be expected in whole East China.

Anthalona harti harti Van Damme, Sinev & Dumont, 2011. Encountered in reservoirs, ponds and paddy fields. For detailed descriptions see Van Damme et al. (2011), for description of Indochina populations see Sinev & Kotov (2012). Distributed in tropical Asia, Mediterranean region, and Africa (Van Damme et al. 2011, Sinev & Kotov, 2012). Recorded for China as Alona verrucosa Sars, 1901 (Chiang & Du, 1973) .

Camptocercus vietnamensis Thanh, 1980 . Rare species, found in Manning reservoir (loc. 34) once in spring. According to Sinev (2011), it is a rheophylous species. For detailed description see Sinev (2011). So far known from Vietnam (Sinev, 2011) and South Korea (Kotov et al., 2012). According to Sinev (2011), the species was probably recorded for China as C. rectirostris by Chiang (1964) and Chiang & Du (1979), but this is the first confirmed record for China.

Camptocercus uncinatus Smirnov, 1971 . Rare, found in three reservoirs, and in a river. For description see Sinev (2014a); for description of East Asian populations see Kotov et al. (2012). C. uncinatus was described from South- East Siberia and is distributed in Southern Europe, Israel, Iraq, Egypt, Ethiopia, Rift Valley of Africa, South-West and East Siberia and Korea (Sinev 2014a). The species was also recorded from Thailand (Maiphae et al. 2008), but these records are not reliable, as no description of specimens were provided and C. uncinatus can be easily confused with C. vietnamensis . This is the first record for China, suggesting that C. uncinatus can be expected in whole East China.

Coronatella rectangula Sars, 1862 . common in all types of water bodies. C. rectangula is a common Palearctic species, distributed from Spain to Far East of Russia, but in East and Central Asia it is substituted by the closely related species Coronatella anemae Van Damme and Dumont, 2008. The south border of C. rectangula distribution is unknown; species is reported from South-East Asia and India. Morphology of Hainan specimens agrees with description of C. rectangula by Frey (1988a) and Van Damme & Dumont (2008), but they have more narrow postabdomen, slightly narrowing in postanal portion. More work on the C. rectangula complex is needed.

Coronatella cf. monacantha (Sars, 1901) . Rare species, encountered in a small reservoir (loc. 19) once in winter. C. monancantha s. str . was described from South America and probably is a Neotropical species (Sinev 2004). C. cf. monacantha is rather common in South-East Asia, being recorded from Thailand, Malaysia, Laos and Cambodia. Oriental populations of the group should be revised; probably they belong to sibling-species C. acuticostata (Sars 1903) .

Coronatella trachistriata (Chen, Zhang & Liu, 1994) . Rare species, encountered in Shuisheng reservoir (loc. 35) in spring. This rare species was previously known from two locations in Wuhan Province of China (Chen et al. 1994), and from Zeya River basin, a tributary of Amur River, Far East of Russia (Kotov et al. 2011a). This species was described as a subspecies of Coronatella rectangula, but it clearly differs from it by morphology of IDL setae, and by absence of setae on basal segment of antenna exopodite. For description of morphology, see Kotov et al. (2011); studied material (see Fig. 1 D–K) fully agrees with the previous description.

Euryalona orientalis (Daday, 1898) . Found in reservoirs, ponds and rivers in both winter and spring. Littoral species, associated with vegetation. For detailed description see Rajapaksa and Fernando (1987b). According to these authors, a common pantropical species. Recorded for China by Chiang & Du (1979).

Graptoleberis testudinaria (Fischer,1851) . Four specimens were found in a reservoir (loc. 41) in spring. Littoral species, associated with macrophytes with submerged leaves. Species recorded worldwide, but probably composes a species-complex. G. testudinaria is rare in South-East Asia, recorded for Thailand and Malaysia only (Korovchinsky 2013). For description of European populations see Alonso (1996).

Karualona karua (King, 1853) . Common in all types of water bodies during winter and spring. Described from Australia and reported from Africa an tropical Asia. All Hainan populations had a similar morphology (Fig. 1 L–Q) and are close to the form reported by Van Damme et al. (2013) from South Thailand; populations characterized by a small basal spine on the postabdominal claw.

Kurzia brevilabris Rajapaksa & Fernando, 1986 . Rare species, found in a pond (loc. 2) once in winter. For detailed description see Rajapaksa & Fernando (1986b). Species of Oriental region (Rajapaksa & Fernando, 1986b). The first record for China.

Kurzia longirostris (Daday, 1898) . Rare species, found twice in rivers (loc. 3, 33) in winter, and once in a pond (loc. 60) in spring. For detailed description see Rajapaksa & Fernando (1986b). Pantropical species; in East Asia penetrating north to the South Korea (Kotov et al. 2012). The species was recorded for China by Chen & Zhang (1990).

Leberis diaphanus (King, 1853) . Rare species, found once in a river (loc. 9) in winter and once in a paddy field (loc. 40) in spring. For detailed description see Sinev et al. (2005); for description of the Indochina populations see Idris (1983, as Alona diaphana), for description of male see Sinev & Sanoamuang (2011). Distributed in Australia, tropical Asia, and Africa. Common in the Oriental region; recorded for China by Chiang & Du (1979) as Alona diaphana .

Leydigia ciliata Gauthier, 1939 . Found in ponds, rivers and paddy fields. Benthic species, associated with muddy or clay bottom. For detailed description see Kotov et al. (2003), for description of male see Sinev & Sanoamung (2011). Known in Africa, tropical Asia and common in Oriental region; recorded for China by Chiang & Du (1979).

Monospilus dispar Sars, 1862 . Rare. Collected in two rivers (loc. 8, 9) in winter. Littoral species, associated with open sandy bottom. For detailed description see Alonso, 1996. Probably a species-complex; M. dispar is common in Holarctic, but was also reported from Africa, Australia and South America. A relative, M. daedalus Kotov & Sinev, 2011 is known from Amur basin and Korea (Kotov & Sinev, 2011; Kotov et al. 2012), but Hainan specimens lack lateral projections on valves characteristic for M. daedalus . In South-East Asia, M. dispar is reported from North Vietnam (Thanh et al., 1980). M. dispar was recorded for China by Chiang & Du (1979).

Notoalona globulosa (Daday, 1898) . Found in spring only, in three reservoirs and in a paddy field. Littoral species, associated with vegetation. For detailed description see Rajapaksa & Fernando (1987c). Distributed in Africa and tropical Asia. Recorded for China as Alonella globulosa by Chiang & Du (1979).

Oxyurella singalensis (Daday, 1898) . Rather rare, but found in all types of water bodies. Littoral species, associated with vegetation. For description see Smirnov (1971) and Idris (1983); for description of male see Sinev & Sanoamuang (2011). Common Oriental species, recorded for China by Chiang & Du (1979).