The Association between Medusa Lychnorhiza lucerna (Scyphomedusae, Rhizostomeae) and Decapod Libinia spinosa (Brachyura, Majidae) Recorded for the First Time in Neritic Waters of Argentina

The paper discusses the first record of the association between the medusa Lychnoriza lucerna Haeckel, 1880 and the decapod Libinia spinosa Milne-Edwards, 1934 in neritic waters of Argentina. Our results allow us to conclude that the symbiotic relation between these two species is a common phenomenon. The crab L. spinosa is located in the subgenital pockets of L. lucerna such that one-half of its cephalothorax is exposed to the outside. The crabs feed at the expense of the medusa, ingesting some portion of its food. A few specimens of the crab have been found, mostly females; the only male was of a somewhat larger size.