Acartia simplex is a species of marine copepod belonging to the family Acartiidae. This species, just under 1 mm in length, is rather similar to Acartia ensifera but can be distinguished by the presence of spines on the dorsal part of the posterior body segment (metasome). Like A. ensifera, it is found around the coasts of New Zealand, mainly in estuarine habitats. References Calanoida Marine crustaceans of New Zealand Crustaceans described in 1905