New records of the rare shrimp parasite Zonophryxus quinquedens Barnard, 1913 (Crustacea, Isopoda, Dajidae): ecological and phylogenetic implications

The rare dajid, Zonophryxus quinquedens represents the only known isopod parasiting on shrimps in Antarctic waters. In contrast to the Bopyridae, which typically live in the gill cavity of their crab host, dajid isopods are normally attached to the carapace of the parasited shrimp. Four specimens of Z. quinquedens Barnard, 1913 were collected in the eastern and western Weddell Sea, Antarctica, during the expeditions ANT XXI/2 in 2003/2004 and ANT XXII/3 in 2005. Molecular phylogenetic analyses, based on small subunit rRNA gene sequences, indicate a close relationship of Z. quinquedens to the Bopyridae. Possible ecological and physiological aspects of the parasite–host interaction are discussed.