A new African lineage of the Daphnia obtusa group (Cladocera: Daphniidae) disrupts continental vicariance patterns

The Daphnia (Daphnia) obtusa group (Cladocera: Daphniidae) is commonly studied, but there is little known of the affinities of African or Asian representatives. We found a new endemic obtusa-like taxon of Daphnia to be common in lakes, pools and puddles of the Bale Mountains of Ethiopia (3857-4100 m.a.s.l.). We provide a phylogenetic analysis using DNA sequences from two mitochondrial genes and a detailed morphological description of this species as Daphnia izpodvala sp. nov. Among the characters that separate D. izpodvala sp. nov. from other members of this group are a large ocular dome, bordered by a distinct pre-ocular and a deep post-ocular depression. The closest relative according to our genetic evidence is North American Daphnia pileata. However, several obtusa-like species remain unexamined. We also found two new lineages in Japan that appear to have no known close relatives. These Japanese species are likely to have been described in the nineteenth century and later falsely synonymized with D. obtusa or other species from Europe. Our results bolster the accumulating evidence for cladoceran regionalism but indicate that strict continental vicariance may not explain the biogeography of the D. obtusa complex.