"Gregaria" to "subrugosa", that is the question: shape changes under laboratory conditions in the pelagic morph of the squat lobster Munida gregaria (Anomura, Munididae).

DIEZ, M.E.; ROJAS, L.; PEREZ-BARROS, P; LEZCANO, A; FLORENTÍN, OLGA; LOVRICH, GUSTAVO A.

JOURNAL OF CRUSTACEAN BIOLOGY

CRUSTACEAN SOC

Lugar: Lawrence, Kansas, USA; Año: 2016

0278-0372

Munida gregaria (Fabricius, 1793) is one of the few species of squat lobsters (Anomura, Munididae) with two morphotypes, one with apost-metamorphic pelagic phase that eventually settles to the bottom (?gregaria?) and a second that is exclusively benthic (?subrugosa?).This study provides the first information on the growth of the pelagic morphotype of M. gregaria and its relation with changes inmorphology in southern South America. Specifically, we studied growth at molt and duration of the intermolt period in the laboratoryand analyzed changes in morphology through growth by means of geometric morphometry techniques. Fifty squat lobsters were sampledfrom shoals in the Beagle Channel, Tierra del Fuego and kept in individual flasks during 29 months. The carapace of each exuviawas photographed and analyzed using 2D geometric morphometry analysis. Changes in shape associated with growth in the gregariamorphotype were gradual, adjusted to a linear function, and occurred mainly in the anterior portion of the carapace. After two years andat least eight molts, however, individuals of the gregaria morphotype were still clearly distinguishable from a typical individual of thesubrugosa morphotype. These results suggests that once sexual maturity is attained, pelagic individuals of M. gregaria do not transformfrom gregaria to subrugosa, and retain the gregaria morphology.