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

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.