Ontogenetic and interspecific variation in body proportions of early juveniles of two mud crab species, Scylla paramamosain and Scylla serrata (Decapoda: Brachyura: Portunidae), under laboratory conditions
Year: 2026
Type: article
Abstract: Ontogenetic changes in body proportions are fundamental to understanding the ecological adaptations of brachyuran crabs during early development. We examined morphometric growth of first- to fifth-instar juveniles of two mud crab species, Scylla paramamosain and S. serrata, reared under laboratory conditions. Generalized additive mixed models were used to evaluate changes in carapace, chela, and pereiopod proportions relative to carapace length. In both species, rapid carapace widening and increases in chela and pereiopod proportions occurred up to approximately 5 mm CL, coinciding with transitions in habitat use and behavior. Chelae and walking legs showed pronounced positive allometric growth, likely enhancing prey capture, predator avoidance, and locomotion in complex mangrove habitats. The fifth pereiopods, functioning in swimming and digging, exhibited ontogenetic increases in dactylus size, suggesting improved burying ability and predator avoidance. Interspecific comparisons revealed that S. serrata had relatively wider carapaces and longer chelae, whereas S. paramamosain had larger pereiopod proportions, particularly in all measured segments of the fifth pereiopod. These findings are discussed in relation to differences in settlement strategies between the two species.
Source: Nauplius
Authors: Tetsuya Sanda, Shigeki Dan, Katsuyuki Hamasaki
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life below water
Open Access status: diamond
OpenAlex ID: W7225118110