A new species of Paranannopus Lang, 1936 (Copepoda, Harpacticoida, Pseudotachidiidae) with atrophic mouthparts from the abyssal of the Angola Basin

AbstractWithin the multicorer deep-sea samples of the DIVA 1 expedition (METEOR cruise M48/1) some male harpacticoid specimens with strongly reduced mouthparts have been collected, each of them representing a hitherto unknown species. Despite their atrophic mouthparts, they can be identified easily as members of the Paranannopinae Por, 1986 because of showing the characteristic swimming-leg sexual dimorphisms of the latter.In the present paper, a species of Paranannopinae with reduced mouthparts is described for the first time. At the present state of systematic discussion the new species has to be placed within Paranannopus Lang, 1936.Males with atrophic mouthparts have been sporadically described also from other harpacticoid families (such as e.g. Argestidae Por, 1986 and Aegisthidae Giesbrecht, 1892) and the phenomenon is likely to be sexually dimorphic. This kind of sexual dimorphism within harpacticoid copepods combined with enlarged antennular aesthetacs seems to be predominantly a deep-sea phenomenon