Relative growth of Dilocarcinus pagei Stimpson, 1861 and Sylviocarcinus australis Magalhães and Turkay, 1996 (Decapoda: Trichodactylidae) at Pantanal of Paraguay River, Porto Murtinho í Mato Grosso do Sul

Abstract

The aim of this work was to determine the equations of relative growth to biometric relations of four categories of individuals, such as adult female, young female, adult male and young male, of Dilocarcinus pagei Stimpson, 1861 and Sylviocarcinus australis Magalhães and Turkay, 1996. Individuals were collected monthly in the Paraguay River, Porto Murtinho County, State of Mato Grosso do Sul, Brazil, between the coordinates 21°41.449’S í  57°33.770’W and 21°42.000’S í  57°33.649’W, from April 1999 to March 2001. The carapace width (CW) vs abdomen width (AW) and carapace width (CW) vs chelar propodus length (CPH) relationships were adjusted to a power function and the allometric coefficients determined for each category. It was analyzed a total of 1,022 individuals of D. pagei and 322 of S. australis. To D. pagei, the positive allometric growth was recorded to adult female in the following relations: AW = 0.6107 CW ^1.0336 and CPH = 0.3687 CW ^1.1291. To S. australis, the same relations were shown isometric: AW = 1.0216 CW ^0.9285 and CPH = 0.5814 CW ^1.0963. Young female shown positive allometric growth to the following relations: AW = 0.1781 CW ^1.3309, to D. pagei, and AW = 0.172 CW ^1.3652, to S. australis. Therefore, it was observed that differences at the organs growth pattern can be correlated with interaction levels that the organs must have with other structures.