Plagusiidae Dana, 1851 and Grapsidae MacLeay, 1838

Plagusids and grapsids are Thoracotremata crabs inhabiting a variety of habitats in the tropical and temperate regions, from marine benthonic communities at 500 m depth (e.g. Euchirograpsus spp.) to intertidal (e.g. Pachygrapsus spp.) or terrestrial habitats (e.g. Geograpsus spp.) Some peculiar cases such as species of Planes live on floating objects, from algae or drifting debris to marine turtles. Larval development of these species is always linked to the sea, and pass through a minimum of 5 zoeal stages and a megalopa. Plagusiidae comprises 5 genera and 20 species, and larval stages are known for 6 of them. Grapsidae comprises 7 genera and 42 species, and for 22 of them there are larval stages known. Although both plagusids and grapsids share larval characters with the rest of the grapsoids, there are a combination of larval features allowing for distinction at a familial level. This leaflet presents the known larval stages of 6 species, out of the 7 (3 plagusids and 4 grapsids) distributed in the ICES area: Euchirograpsus americanus, E. liguricus, Plagusia depressa, Pachygrapsus gracilis, P. marmoratus, P. transversus, and Planes minutus. The leaflet includes a key to identifying zoea and megalopa stages of these species.