Diversidade de crustáceos decápodes em riachos do cerrado do Maranhão - Brasil

Abstract

The fauna of freshwater crustaceans is widely distributed in Brazil, being dominated by crabs of the family Trichodactylidae H. Milne-Edwards, 1853 and the prawns of the genus Macrobrachium Bate, 1868 of the Palaemonidae family. The State of Maranhão does not have enough studies on freshwater crustaceans, thus, this is the first study to provide an update on the knowledge of the genus Macrobrachium and the family Trichodactylidae for the eastern region of Maranhão. Eight streams of the East of Maranhão were sampled with hand nets, sieves and trawl, passed in the bottom and submerged marginal vegetation for a period of 20 minutes in a stretch of 150m. A total of 526 specimens of shrimp were collected in five species: Macrobrachium amazonicum (Heller, 1862) (N=119), M. acanthurus (Wiegmann, 1836) (N=116), M. carcinus (Linnaeus, 1758) (N=01), M. jelskii (Miers, 1877) (N=235) and M. olfersii (Wiegmann, 1836) (N=55). We also registered 22 specimens of Trichodactylidae crabs, distributed in four genera and four species: Goyazana castelnaui (H. MilneEdwards, 1853) (N=6), Dilocarcinus septemdententatus (Herbst, 1783) (N=11), Sylviocarcinus pictus H. Milne-Edwards, 1853) (N=3) and Valdivia serrata White, 1847 (N = 2). The species M. carcinus and M. olfersii were registered for the first time in the State, increasing the number of species of freshwater prawns in Maranhão, from four to six species. We have also developed an identification key of the genus Macrobrachium for the State. Thus, we confirm the records of these species for the State and the extension of their distribution area, with maps of occurrence.