Relative growth and morphological sexual maturity of the mangrove crab Aratus pisonii (H. Milne Edwards, 1837) (Decapoda, Brachyura, Sesarmidae) on the southern coast of the state of São Paulo, Brazil

Abstract

Growth in crustaceans is characterized by ontogenetic differentiation during the development of their body structures, so studies on relative growth are widely applied in this group. In this study, the growth pattern of the body structures was verified through the analysis of relative growth, and then, morphological sexual maturity of the mangrove crab Aratus pisonii (H. Milne Edwards, 1837) was estimated. The carapace width (CW), cheliped propodus length (PL), cheliped propodus height (PH), propodus width (PW), abdomen width (AW), and first pleopod length (FPL) of the crabs were measured. The relationships that best showed changes in the allometric coefficient among demographic categories were FPL vs. CW for males and AW vs. CW for females. This study verified the increased size of the cheliped in terms of length, width, and height, which occurred mainly in adult males. This increase reflects the importance of this structure in the reproductive processes of A. pisonii. For females, the increase in abdomen growth reflects their reproductive potential, since it is a structure that provides protection for eggs.

Keywords:

• allometry
• development
• reproduction

Acknowledgments

The authors are grateful to “Fundação de Amparo à Pesquisa do Estado de São Paulo” (FAPESP) Scholarship (#2013/12136-4 To RAP), Thematic Biota (#2010/50188-8 to RCC), “Conselho Nacional de Desenvolvimento Científico e Tecnológico” (CNPq) for Research Scholarships (PQ 304784/2011-7) to (RCC) and (CAPES) Scholarship (TMD). We also thank the LABCAM coworkers for help during field work, Msc. João Alberto Farinelli Pantaleão for illustration of body dimensions, and Dr Gustavo Luis Hirose for assisting in the analysis. All experiments conducted during this study complied with current applicable state and federal laws in Brazil.