A study of parasitic crustaceans attaching themselves inside the branchial cavities (the gills) of their fish hosts was recently conducted in order to reveal potentially unrecognised diversity of the genus Elthusa in South Africa.
While there had only been one species known from the country, a new article published in the open-access journal ZooKeys adds another three to the list.
For one of them, the research team from North-West University (South Africa): Serita van der Wal, Prof Nico Smit and Dr Kerry Hadfield, chose the name of the fictional character Xena, the warrior princess. The reason was that the females appeared particularly tough with their characteristic elongated and ovoid bodies. Additionally, the holotype (the first specimen used for the identification and description of the previously unknown species) is an egg-carrying female.
Formally recognised as Elthusa xena, this new to science species is so far only known from the mouth of the Orange River, Alexander Bay, South Africa (Atlantic Ocean). It is also the only Elthusa species known to parasitise the intertidal Super klipfish (Clinus supercilious). In fact, this is the first time an Elthusa species has been recorded from any klipfish (genus Clinus).
To describe the new species, the scientists loaned all South African specimens identified as, or appearing to belong to the genus Elthusa from both the French National Museum of Natural History (Paris) and the Iziko South African Museum (Cape Town).
van der Wal S, Smit NJ, Hadfield KA (2019) Review of the fish parasitic genus Elthusa Schioedte & Meinert, 1884 (Crustacea, Isopoda, Cymothoidae) from South Africa, including the description of three new species. ZooKeys 841: 1-37. https://doi.org/10.3897/zookeys.841.32364