TOWARD THE UNDERSTANDING OF BEING SEXUALLY MATURE IN THE FEMALES OF THE SPIDER CRAB Leurocyclus tuberculosus (Majoidea) FROM GOLFO NUEVO, ARGENTINA.

GONZALEZ PISSANI, X.; BARÓN, PEDRO J.; LÓPEZ-GRECO, LAURA S.

La Serena, Chile

Congreso; The Crustacean Society Mid Year Meeting 2007; 2007

The Crustacean Society and Universidad Católica del Norte

Majoidea are known for having determinate growth with puberty moult (PM) being the last moult. Within the Eubrachyura, the PM is usually studied by means of morphometrical approaches that involve the change in the relative growth of the abdomen width (AW) related to a reference dimension (carapace width, CW or carapace length, CL). This work was aimed at determining the main features that change when PM occurs in Leurocyclus tuberculosus from golfo Nuevo (42ºS) Argentina. For this purpose 198 females were collected, measured and the following characters were observed: the absence/presence of the gonopores and their form, the shape of the pleon, the presence of eggs and the shape and color of the ovaries. According to the morphometric approach, the PM occurs between 40.33 mm and 48.43 mm CW. Immature females present a flat pleon, absence of gonopores below (8.06 mm CW) or presence but little differentiated gonopores and not developed ovaries neither seminal receptacles. The mature females have a rounded and convex pleon, open gonopores, developed ovaries varying in size and colour (white, pale orange, orange or red) according to the degree of ovarian maturation and seminal receptacles clearly differentiated. Ovigerous females were only recorded in females sized above 40.33 mm CW. These results show a similar pattern than Inachus and Maja species in which the PM represents both the change in shape of the pleon and the developing of the gonads and it is different from the genus Chionoecetes and Hyas in which although the change in shape of the pleon is evident at PM, the ovaries begin to develop during the immature stage. Since Majoidea is a taxon under discussion from the phylogenetic point of view, we consider that this kind of studies about functional morphology could be another tool for studying the relationships within this taxon. Financial support: PIP-CONICET 5835, PICT-ANPCYT 14700.Leurocyclus tuberculosus from golfo Nuevo (42ºS) Argentina. For this purpose 198 females were collected, measured and the following characters were observed: the absence/presence of the gonopores and their form, the shape of the pleon, the presence of eggs and the shape and color of the ovaries. According to the morphometric approach, the PM occurs between 40.33 mm and 48.43 mm CW. Immature females present a flat pleon, absence of gonopores below (8.06 mm CW) or presence but little differentiated gonopores and not developed ovaries neither seminal receptacles. The mature females have a rounded and convex pleon, open gonopores, developed ovaries varying in size and colour (white, pale orange, orange or red) according to the degree of ovarian maturation and seminal receptacles clearly differentiated. Ovigerous females were only recorded in females sized above 40.33 mm CW. These results show a similar pattern than Inachus and Maja species in which the PM represents both the change in shape of the pleon and the developing of the gonads and it is different from the genus Chionoecetes and Hyas in which although the change in shape of the pleon is evident at PM, the ovaries begin to develop during the immature stage. Since Majoidea is a taxon under discussion from the phylogenetic point of view, we consider that this kind of studies about functional morphology could be another tool for studying the relationships within this taxon. Financial support: PIP-CONICET 5835, PICT-ANPCYT 14700.