Morphometric relationships as proxies for reproductive maturity in the clam Anomalocardia flexuosa (Linnaeus, 1767)

The objective of this study was to describe the morphometric relationships between different shell dimensions of the bivalve Anomalocardia flexuosa, to check the changes in the growth pattern, and to determine the adult and juvenile phases and the size of sexual maturity of the species using morphometric measurements. Considering the 52,873 specimens measured in the present study, all the allometric relationships established for A. flexuosa were significant, and both the relations between length × height and length × width showed positive allometry. The K means clustering separated the dataset between juveniles and adults and defined 13.20–14.60 mm shell as the interval of length for the transitional phase. The growth pattern was significantly different between juveniles and adults, in which juveniles presented isometric growth and adults had a negative allometric growth. The fit of the logistic model indicated that the shell length at sexual maturity was 13.80 mm. The A. flexuosa juvenile shell had a more rounded shape than the adult. Processes related to animal development and environmental characteristics may influence the shell shape. The maturity size found in the present study is according to the range of maturity proposed in the literature.