Morphological variability of the megalopa of Liocarcinus depurator (Brachyura: Portunidae) in Mediterranean and Atlantic populations

Abstract

Megalopae of the portunid crab Liocarcinus depurator were captured from the plankton in the western Mediterranean and northeastern Atlantic. The megalopa stage is morphologically described and illustrated and compared with other previous descriptions of this stage in the species. The Mediterranean megalopae showed intrapopulational variability in setation, and meristic and morphometric characteristics showed important differences when compared to previous descriptions from the Atlantic populations. The Atlantic plankton specimens described herein are more similar to Mediterranean megalopae than previous descriptions of the megalopa stage of the species obtained from laboratory‐reared material from North Atlantic populations. This study shows that, even in morphological characters considered conservative, meristic variation may be found.