| Popis: |
Dimorphism and size at sexual maturity were determined by the allometric equation for a population of Cancer plebejus Poeppig from the South of Chile. Eleven morphometric variables were measured and the cephalothorax width (AnC) was used as a reference parameter. A prepubertal molt was identified only for females between 41 and 48 mm AnC by the variation in the relative growth of the maximum diameter of the gonopore. Sexual maturity occurs in females within the range of 63 to 70 mm AnC and is expressed by the changes in the relative growth of the propodus and dactylus of the chelipeds, abdomen, and merus of the fifth pereiopod. Males undergo their pubertal molt between 77 and 96 mm AnC, as is shown by changes on the relative growth of the dactylus and propodus of the chelipeds and by the length of the first pleopod. Sexual dimorphism starts to be evident from the prepubertal phase mainly by the dimensions of the cephalothorax, abdomen, and chelipeds which increase after the pubertal molts. Finally, the adaptative significance of the changes in the relative growth rates of the different morphometric parameters analyzed are discussed. |
