Relative growth and sexual maturity of the spider crab Libinia spinosa Guérin, 1832 (Brachyura: Majoidea: Epialtidae), from the Southeast Brazilian coast

ABSTRACT

We investigated the relative growth and sexual maturity (gonadal and morphometric) of Libinia spinosa. Crabs were sampled at Ubatuba from January to December 2000, using trawls. Based on allometric growth, males were grouped into juveniles (MJ), adolescents (MAd) and adults (MA) based on the relationship CPL (major cheliped propod length) vs. CW (cephalothorax width), all with positive allometric growth. For females, the relationship AW (abdomen width) vs. CW allowed segregating juveniles (FJ) from adults (FA), with positive allometric growth for FJ but isometric growth for FA. The morphometric maturity evidenced for MAd varied from 33.7 mm to 34.5 mm and for MA and FA. The size at which 50% of individuals reach the morphometric sexual maturity was L₅₀ = 50.1 mm for males and L₅₀ = 37.3 mm for females. Gonad maturity was L₅₀ = 33.7 mm for males and L₅₀ = 36.9 mm for females. Through relative growth analyses, we identified an adolescent male group (prepuberal phase). These individuals presented mature gonads, enabling them to copulate with females. These adolescent males may reproduce while avoiding competition with adult males, as it happens in other species of Majoidea that present more than two morphotypes in the population.

KEYWORDS:

• Allometry
• gonad development
• males morphotypes
• sizeMat
• Latitudinal variation

Acknowledgments

We would like to thank Adilson Fransozo (PhD) for permission to use data. Santos, MP (Msc) and Negreiros-Fransozo, ML (PhD) thank the Zoology Program of the Biosciences Institute, University of the State of São Paulo (UNESP, Botucatu, Brazil) for the logistic support and to the National Council for Scientific and Technological Development (CNPq) for his Master of Science fellowship [131450/2019-0]. Negreiros-Fransozo, ML (PhD) and Costa, RC appreciate the grant from CNPq, respectively, as a Research fellow (#302691/2015-4; classification 1B to MLNF and #306672/2018-9 for RCC). All the samplings were in compliance with State and Federal laws. Authors are grateful to Josymar Torrejon-Magallanes (PhD), Gabriel Fellipe Barros Rodrigues (PhD) and Alexandre Ribeiro da Silva (PhD) for all statistical support. We would also like to thank the anonymous referees for their valuable comments in the manuscript.

Data availability statement

The data that support the findings of this study are available upon reasonable request from the corresponding author.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq [131450/2019-0; 306672/2018-9].