Abergasilus amplexus is a species of parasitic copepodendemic to euryhaline habitats in New Zealand. It is the only known species in the genus Abergasilus.
Description
This species is unique among ergasilids in that it only has three pairs of legs: the fourth and fifth pairs are reduced to single spines or are completely absent.[1] The second antenna is very distinctive, hooks on the last and penultimate segments creating an obviously claw-like structure, more obvious in the female.[1] The male is free-living, forming part of the plankton.[2] Both sexes have an average length of 0.5 mm.[2]