Anthalona, Van Damme, Sinev & Dumont, 2011

DAMME, KAY VAN, SINEV, ARTEM YU & DUMONT, HENRI J., 2011, Separation of Anthalona gen. n. from Alona Baird, 1843 (Branchiopoda: Cladocera: Anomopoda): morphology and evolution of scraping stenothermic alonines, Zootaxa 2875 (1), pp. 1-64 : 58

Distribution of Anthalona gen. n.: a stenothermic genus

Anthalona gen. n. has its main distribution in the southern hemisphere ( Fig. 30 ) and appears composed of only stenothermic species. The northern limit of Anthalona distribution is the Mediterranean, not occurring higher than latitudes of around 40°N ( A. mediterranea in Turkey and perhaps China ( Yalim & Ciplak 2005; Chen et al. 1991), A. harti in Spain ( Alonso 1996; as verrucosa ). Ecological preferences are the shallow littoral, rich in flocculent detritus and vegetation of temporary pools or floodplains, on sandy or rocky substrates. Observations of live Anthalona verrucosa and A. mediterranea show that these animals thrive very well on sandy substrates and under warm conditions (e.g., Van Damme & Dumont, 2010). They are all poor swimmers, mainly moving between filamentous algae (very closely associated), detritus and on the substrate; in high numbers, they enter the water column. Anthalona may be relatively rare in the Neotropics (Paggi, op. cit.), while in Afro-Asia, they are common in shallow lakes, ponds, ricefields, etc. (e.g. Idris 1983). Animals may tolerate strong acidity (pH 4.2) in temporary dune pools between Utricularia , as found in the Lençóis Maranhenses, but this is the probably the limit (no large populations at this pH) ( Van Damme & Dumont 2010).

So, as opposed to the Alona quadrangularis group ( Van Damme & Dumont 2008a), which tolerates cold conditions, Anthalona is a stenothermic genus, which never adapted to cold. This is also markedly different in distribution with the genus Coronatella . The latter colonized northern waters above 40°N, with Coronatella rectangula and C. circumfimbriata ( Van Damme & Dumont 2008b) ; our revision shows that Anthalona gen. n. is absent from higher latitudes. The distribution of Anthalona gen. n. corresponds to that of several tropical taxa of the Coronatella -clade (like Leberis and the A. monacantha- and A. dentifera- group) and with the two-pored Karualona . Within the genus, the Anthalona verrucosa -complex appears pantropical, while a few species have limited distributions to current knowledge (e.g., Anthalona brandorffi , A. simplex n. sp. and A. acuta n.sp). Three species are from South America: A. verrucosa , A. brandorffi and A. acuta n. sp. A. verrucosa and A. acuta may coexist in a single waterbody (NE-Brazil, Lençóis Maranhenses), discussed in the following section.

Figures

FIGURE 30. Distribution of type localities of available names (A) and species in Anthalona gen. n. (B) considered valid after this study. Only confirmed records are shown. Horizontal line in B delimits distribution of Anthalona to the north, at 40°N. The genus is common in the Southern Hemisphere; most records have been regarded as Alona verrucosa and should now be evaluated.