Filling gaps in the biology of the endemic and threatened freshwater shrimp Macrobrachium candango (Caridea: Palaemonidae) through basic morphometric and reproductive approaches

Abstract

Macrobrachium candango Mantelatto, Pileggi, Pantaleão, Magalhães, Villalobos and Álvarez, 2021 is an endemic shrimp species to the Brazilian Central-West region (Brasília, Federal District). The present study aims to analyze the relative growth, morphometry, morphological sexual maturity, and fecundity of this species. Specimens were collected from tributaries of the Paranoá Lake hydrographic basin, Brasília, during sporadic periods between 1983 and 2012. Relative growth was analyzed for different structures (carapace, abdomen, second abdominal pleura, merus, carpus, and propodus). The laterality and heterochely patterns were evaluated based on the dimensions of the propodus length. Fecundity was calculated as the average total number of eggs per female and egg size was measured to obtain the volume. There were differences in relative growth (p < 0.05) of the structures analyzed

Relative growth and morphological sexual maturity of the caridean prawn Macrobrachium villosimanus (Tiwari, 1949) (Decapoda: Palaemonidae)

“…This finding is consistent with other studies (Berglund, 1981; Boschi, 1974; Cartaxana, 2003; Kim, 2005; Koshy, 1969) that reported males of the palaemonid species are generally larger, with a highly evident sexual dimorphism. Several other studies reported this size predominant is frequently observed in species of Macrobrachium Spence Bate, 1868, mainly being associated with size and form of the chelipeds of adult males (Boschi, 1974; Nogueira et al, 2023; Nogueira, Mossolin, et al, 2022; Rossi et al, 2022; Santos et al, 2022). Bauer et al (2014) reported that, for many caridean species, males are significantly larger than females for ‘temporary mate guarding’ or ‘neighborhood of dominance’ mating systems, and that they use hypertrophied weapons (major chelipeds, third maxillipeds) to fight for and defend females.…”