Morphometric changes at terminal molt and reproductive capacity in the kelp crab Pugettia ferox Ohtsuchi & Kawamura, 2019 (Decapoda: Brachyura: Majoidea).

This article focuses on the morphological changes at terminal molt and the reproductive capacity of pre-terminal molt males in the kelp crab Pugettia ferox (Majoidea, Epialtidae). The study establishes morphometric criteria distinguishing pre- and post-terminal molt stages based on relative claw length in males and pleon width in females, and identifies two developmental stages within pre-terminal molt males: immature and adolescent. Laboratory mating experiments demonstrated that adolescent males, despite not having undergone terminal molt, were behaviorally and physiologically capable of mating and producing viable offspring, indicating functional maturity prior to morphological maturity. Seasonal data suggest that terminal molting and breeding occur from winter to summer, with potential ecological implications for the species' life history and coastal ecosystem roles.