Published online by Cambridge University Press: 11 May 2009
A new genus, Mesoikopleura, in the family Oikopleuridae (Lohmann, 1915), is described from several specimens collected at low mesopelagic depth (710–860 m) during different cruises using the ‘Johnson-Sea-Link’ submersibles, and from one collected by the ‘Cyana’ submersible during the ‘Gyrocean’ cruise. Three species of this new genus are described: M. enterospira, M. youngbluthi and M. gyroceanis. One of the species already described as belonging to the genus Pelagopleura is moved to the genus Mesoikopleura. Consideration of the genera closely related to Mesoikopleura leads to the division of the subfamily Oikopleurinae into two groups at the level of super genera: Labiata and Alabiata.