A new species of the seasonal killifish genus Moema (Cyprinodontiformes: Rivulidae) from the Piraí watershed in the Southwest Amazon basin

Abstract Moema, a genus of the Rivulidae family, currently comprises 20 valid species. Most these species inhabit temporary pools in Amazon basin and only one is found upper Paraguay basin. A new member this from Río Madeira drainage here described. Males differ all congeners by combination color pattern consisting oblique, sometimes chevron-like, irregular rows red light blue double-dots on body; dark yellowish to golden pectoral fins with no visible markings; stripe ventral section caudal fin very narrow black marginal line, intermittent or even absent. The existence infrageneric groups within geographic distribution taxonomic aspects present Ríos Mamoré Iténez/Guaporé rivers drainages, observation intraspecific aggression between males amphibious lifestyle are discussed.