Heptnerina confusa n. gen., n. sp. (Copepoda, Cyclopoida, Cyclopinidae) was gathered during in situ colonization experiments at the Mid-Atlantic Ridge (37°N), at a depth of 1698 m. The new genus is close to the heterogeneous genus Cyclopina Claus, 1863 and differs from the type species Cyclopina gracilis Claus, 1863 in the antenna, which has two exopodal setae, and in other details. The affinities of the new genus with the cyclopinids Troglocyclopina balearica Jaume & Boxshall, 1997 and Cyclopina esilis Brian, 1938 are also discussed. The detailed description reveals several primitive characters, such as the separate praecoxa and coxa of the maxilliped. One of four setae of one-segmented exopod of maxillule is shorter and armed with setules on tip. The presence of setae on the paragnaths is a new discovery for Cyclopinidae. The small internal segment of leg 5 is considered to represent the endopod and is interpreted as a reversal in the Cyclopoida.
Crustacea, Copepoda, Cyclopinidae, Heptnerina confusa n. gen., n. sp., deep-sea hydrothermal vents, Atlantic Ocean, new genus, new species.