Composição específica e distribuição da fauna de caranguejos de água doce (Crustacea: Decapoda: Brachyura) no estado de Roraima, Brasil

Abstract

The state of Roraima is drained in almost its entire surface by the watershed of the Branco River. This drainage has diverse aquatic habitats still poorly known from the scientific point of view. This study aimed to survey the specific composition and geographical distribution of freshwater crab fauna from Roraima. The survey was based on specimens deposited in the crustacean collections of the Museu Integrado de Roraima (MIRR), Boa Vista, and the Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus. In addition, samples were taken in ten municipalities (Amajari, Bonfim, Cantá, Caracaraí, Caroebe, Normandia, Pacaraima, São Luiz do Anauá, São João da Baliza, and Rorainópolis) covering regions of “Lavrado”, forests, flooded forests and upland areas and low elevations. The collection of crabs was performed using dip net with 1 mm mesh, sampling all habitats of the streams, such as the submerged litter, aquatic vegetation, edges of ravines, hollows of submerged tree truncks, trying to cover all microhabitats possibly occupied by crabs. Traps were also used (locally known as "Covo"), with dead bait and commercial cat food. A total of eleven species of crabs were recorded from Roraima: four of Trichodactylidae: Moreirocarcinus laevifrons, Poppiana dentata, Sylviocarcinus pictus and Valdivia serrata; and seven of Pseudothelphusidae: Fredius beccarii, Fredius estevisi, Fredius fittkaui, Fredius platyacanthus, Fredius stenolobus, Kingsleya ytupora and Kingsleya latifrons. Additionally, identification keys are provided to families, genera and species, as well as geographic distribution maps for each species. Among these, Moreirocarcinus laevifrons, Fredius beccarii, Fredius fittkaui, and Kingsleya ytupora are recorded for the first time in Roraima; additionally, Fredius beccarii is recorded for the first time from Brazil.