Chydoridae Dybowski et Grochowski, 1894

Soesbergen, Martin & Sinkeldam, Jos, 2019, An annotated checklist of the Branchiopoda (Crustacea) of the Dutch Caribbean islands, Zootaxa 4701 (1), pp. 25-34 : 28-29

Family Chydoridae Dybowski et Grochowski, 1894

On Klein Bonaire, an unidentified Alona species was found at Pos Calbas ( Rammner 1933), this species could belong to Alona or several genera split off of Alona . Two other species of Alona were identified.

Leberis davidi (Richard, 1895) . Rammner (1933) found Alona davidi Richard, 1895 in a well in Bronswinkel at Pos Hoeba, in a small oligohaline lake. It is a valid species, now placed in the genus Leberis Smirnov, 1989 ( Sinev et al. 2005; Van Damme et al. 2010). A. davidi was described from Haiti and is widespread in Middle and South-America. Three species of Leberis are present in the neotropics ( Neretina & Sinev 2016); the others being L. chihuahuensis , a cryptic species, found in Mexico ( Elías-Gutiérrez & Valdez-Moreno 2008), and L. colombiensis Kotov & Fuentes-Reinés, 2015 found in Colombia ( Kotov & Fuentes-Reinés 2015). The postabdomen depicted in Rammner (1933) shows a short basal spine (0,24 times the length of the postabdominal claw) and no strong setae in the lateral fascicles. This is the case for L. davidi but not the two other species ( Kotov & Fuentes-Reinés 2015).

Ovalona glabra ( Sars, 1901) . Rammner recorded Alona cambouei de Guerne & Richard, 1893 on Bonaire in Pos di Tanki Onima. It was found in a small walled basin at 30°C. A. cambouei belongs to the Alona pulchella group ( Van Damme et al. 2010) and is often confused with the Neotropical A. glabra Sars, 1901 and the Australian A. pulchella King, 1853 ( Van Damme 2010). A. cambouei is an African and Asian species. It was transferred to Ovalona Van Damme et Dumont, 2008 ( Sinev 2015) .

Rammner (1933) is very clear in his description: ‘Mit dieser Art [ A cambouei de Guerne & Richard, 1893 ] stimmt sie so gut überein, daβ sich eine nähere Beschreibung erübrigt; er kann auf die Originalbeschreibung verwiesen worden‘. Translated: ‘With this species [ A. cambouei de Guerne & Richard, 1893 ] it is corresponding so well, that only a reference to the original description is needed‘. A. glabra (now O. glabra ) resembles A. cambouei (now O. cambouei ) very close. There were, at that time, no detailed studies of these species, so it is very probable that he confused them. A. cambouei is described as having polygons with a dot inside ( De Guerne & Richard 1893). Smirnov (1974) uses this feature to key out this species. O. glabra , found on 8 September 2008 in St Maarten, clearly shows this pattern. Sinev (2015) describes O. cambouei as smooth (p. 481), which differs from the original description. The descriptions of O. glabra by Sars (1901) and Sinev (2001a) reveal that this species is smooth, hence the name. Presence or absence of polygons are, according to Sinev (2001b), not adequate to distinguish species. Sinev (2001b) uses the number of setae at the ventral side of the shell to distinguish A. glabra . The number of setae of the animal collected in 2008 is around 50 and indicates O. glabra ( Sinev 2001b) .

Two other taxa should be taken into account: Ovalona kaingang ( Sousa et al. 2015) and Ovalona setulosa arangureni (Sinev & Fuentes-Reinés 2016) . A comparison of the main morphological differences between O. setulosa arangureni and O. glabra (Sinev & Fuentes-Reinés 2016) shows that it is not O. setulosa arangureni . O. kaingang occurs in the southern Neotropical region. It has a spine on the first segment of the exopodite of the antenna equal in length as the second segment ( Sousa et al. 2015). This spine in the collected animal is shorter than the second segment, indicating this is O. glabra . O. glabra is common in the neotropics from Argentina to Mexico and South- East USA ( Sinev, 2015).