Alona Baird, 1843

Elías-Gutiérrez, Manuel, Jerónimo, Fernando Martínez, Ivanova, Natalia V., Valdez-Moreno, Martha & Hebert, Paul D. N., 2008, DNA barcodes for Cladocera and Copepoda from Mexico and Guatemala, highlights and new discoveries, Zootaxa 1839 (1), pp. 1-42 : 11-12

Genus Alona Baird, 1843 and Leberis Smirnov, 1989

Sinev et al. (2006) recently moved Alona diaphana - davidi to the genus Leberis . Our barcode results agree with this proposal, because we observed more than 19% divergence between this genus and the most closely related species of Alona . We encountered two species belonging to the L. davidi complex, one close to L. davidi Richard s. str., while the other represents a related form that proved to be a new species (Elías-Gutiérrez & Valdez-Moreno 2008). Both phenotypes showed clear morphological differences in the second antenna, thoracic limbs and male postabdomen.

Alona dentifera ( Sars, 1901) was divided in two groups, again with allopatric distributions. Alona cf. dentifera was found in the south, while A. dentifera was found in the northern semi-desert. Unfortunately, only one specimen from the south could be sequenced, so its taxonomic status remains uncertain. Interestingly, both members of the A. dentifera cluster showed less barcode divergence from species of Leberis than from other species of Alona . Sinev et al. (2004) concluded, based on morphological analyses, that there are no reasons to exclude A. dentifera from Alona , although it presents a combination of unique and rare characters, most considered as autapomorphies. Our data suggest that A. dentifera is not a “marginal” species of Alona , as concluded by Sinev et al. (2004), but rather a separate taxon with more than 19% divergence from the rest of the genus.

Among the “true” Alona , we obtained sequences from A. setulosa Megard and A. glabra Sars, 1901 , the latter first described from Argentina. Although these two species are difficult to separate morphologically ( Megard 1967), they are clearly valid species as evidenced by their high barcode divergence. Alona glabra was itself divided into two related genotypes, each broadly distributed from Guatemala to the north of Mexico, with several localities within the Cuatro Ciénegas semi-desert region. It seems that the related form from the north represents a different species.