Copepods of the family Acartiidae are representatives of Calanoida. Common and abundant in marine zooplankton worldwide, the 86 recognized species of Acartiidae are grouped into 5 genera. They occur in neritic waters covering a wide latitudinal range. Adult body lengths range between 600 µm and 2700 µm, a size that is effectively captured by meso-zooplankton nets of 200 µm mesh size. Juveniles and nauplii, however, are smaller; they can only be quantitatively captured by using narrower mesh sizes. Adults show sexual dimorphism recognizable only after the first instars of the copepodite stage. This leaflet presents the following:
i) a key for the identification of the five genera included in the family Acartiidae; and
ii) the morphological features of 21 species and 1 variety considered as certain (among the 37 species+ 2 varieties reported) that belong to the genera Acartia, Paracartia, Pteracartia and occur in the eastern North Atlantic and Ponto-Mediterranean region.
A key to all these taxa is presented. This leaflet is an update of Plankton Identification Leaflet 181 (Bradford-Grieve, 1999a) in which 19 species plus 2 varieties were included and it is predominantly based upon Razouls et al. (2005–2020).