New Sensiava species (Copepoda: Calanoida: Diaixidae) from the deep South Atlantic and first description of the female.

Females are described for the first time in the genus Sensiava Markhaseva & Schulz, 2006, that was known previously only from males. Four species of this genus are identified from samples collected in the vicinity of the abyssal sea bed. Two species, Sensiava secunda sp. nov. and S. peculiaris sp. nov. are named, and two species are not given names due to a poor condition of the examined specimens and their incomplete descriptions. Sensiava males have also been found in the samples. They share with their male congener Sensiava longiseta Markhaseva & Schulz, 2006 a geniculate right antennule, which is a plesiomorphy observed only in the benthopelagic Clausocalanoidea Giesbrecht, 1893. A differential diagnosis for the genus is given, based on both sexes. Sensiava was previously known only from the Antarctic waters between 63-64ºS, but its distributional range now can be extended significantly further to the north, up to the Equator in the South Atlantic.