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

MARIANO J. DIEZ; MARÍA LAURA ROJAS-QUIROGA; PATRICIA PÉREZ BARROS; ANÍBAL LEZCANO; OLGA FLORENTÍN; GUSTAVO A. LOVRICH

JOURNAL OF CRUSTACEAN BIOLOGY

CRUSTACEAN SOC

Lugar: Lawrence, Kansas, USA; Año: 2016 vol. 8 p. 530 - 537

0278-0372

Munida gregaria (Fabricius 1793) is one of the few species of the family Munididae withtwo morphs, one with a post-metamorphic pelagic phase that eventually settles to thesea-bottom and the other being exclusively benthic, known as "gregaria" and"subrugosa". This study provides the first information on growth of the pelagic morph ofMunida gregaria and its relation with changes in morphology in southern SouthAmerica. Specifically, we studied growth at molt and duration of the intermolt period inthe laboratory, and analyzed changes in shape through growth by means of geometricmorphometry techniques. Fifty squat lobsters were sampled from shoals in the BeagleChannel and kept in individual flasks during 29 months. The carapace of each exuviaewas photographed and analyzed using 2D geometric morphometry analysis. Changesin shape associated with growth in gregaria were gradual, adjusted to a linear function,and occurred mainly in the anterior zone of the carapace. However, after two yearsand at least 8 molts, individuals of the gregaria morph were still clearly distinguishablefrom a typical individual of the subrugosa morph. These results suggests that once thesexual maturity is attained, pelagic individuals of Munida gregaria do not transformfrom gregaria to subrugosa, and retain the gregaria morphology.