Valdivia serrata White, 1847

Valdivia serrata White, 1847 View in CoL

( Fig. 1D View Figure 1 , 2D View Figure 2 )

Material examined. Brazil, state of Maranhão, Barreirinhas municipality, Passagem do Canto stream (02°50’45.2”S 42°51’48.8”W), 22.X.2014, 2 males (16.34‒27.16 mm CW and 14.38‒23.17mm CL) ( CIASB M.2017.0001. UFSB) GoogleMaps .

Distribution. Orinoco and Amazon river basins, as well as on coastal rivers of northern South America, in Venezuela, Colombia, Guyana, Suriname, Brazil, Peru, and Bolivia ( Magalhães, 2002; 2003a; Bernards, 2008; Alves et al., 2010; Lima et al., 2013).

This research adds new occurrence records for G. castelnaui , S. pictus , V. serrata , and D. septemdentatus . It is important to emphasize that in this study V.serrata was recorded for the first time in the Preguiças river basin, while D. septemdentatus and S. pictus were registered for the first time in the Munim river basin.

This research established new occurrence areas for freshwater crabs on the eastern region of the state of Maranhão. Furthermore, the number of hydrographic basins in the state of Maranhão with occurrence of freshwater crabs increased from three to five ( Tab.1). Thus, according to our results, the knowledge of freshwater crustaceans of the state of Maranhão is underestimated ( Andrade et al., 2017). Therefore, a species catalog is urgently needed to understand species diversity in all hydrographic basins, considering possible consequences upon environmental modifications in several basins and sub-basins, such as pollution problems and deterioration of aquatic environments. The few studies available only provide sparse records, thus emphasizing the importance to survey the crustacean fauna in state of Maranhão. Moreover, other studies focusing on the comprehension of population and biological aspects in several basins are necessary to compare possible environmental damages.