Morphological sexual maturity of the freshwater anomuran crab Aegla parana (Crustacea, Decapoda, Aeglidae) from Negro River Sub-basin, Upper Iguaçu Basin, southern Brazil

Abstract

The carapace length (CL) at the onset of morphological sexual maturity (MSM) in Aegla paranaSchmitt, 1942was estimated in a population located at Negro River Sub-basin, Upper Iguaçu Basin, southern Brazil. The animals were captured with Surber net and with baited traps in Negro River and in its tributary Totó River, in December/2017, June and July/2018. Carapace length of each individual was measured from the tip of the rostrum to the posterior margin of the carapace, with a digital caliper or under a digital microscope. Length of the major cheliped propodus (LMAP) of males and width of the abdomen (LA) of females were measured for relative growth analysis. The CL at the onset of MSM was estimated as the inflection points on the scatter plots with the REGRANS program. In Negro River, 107 males (CL range 6.90- 50.25 mm) and 95 females (10.37-39.36 mm) were obtained, while in Toto River, 225 males (4.92-25.65 mm) and 160 females (5.18- 26.45 mm). MSM is attained by males at 23.15 mm CL and females at 17.85 mm CL. The smallest ovigerous female measured 19.00 mm CL. Aegla parana reaches the highest maximum size and males attain MSM with the highest CL value among the known species of the genus.