Nothobranchius niassa (Cyprinodontiformes: Nothobranchiidae), a new species of annual killifish from northern Mozambique

Nothobranchius niassa, new species, is described based on specimens collected in pools within seasonal streams in upper catchments of the Rovuma River, Niassa Reserve, northern Mozambique. It differs from its congeners by a unique combination of characters: dorsal fin rays 15-18, anal fin rays 15-17, light blue iris, light blue dorsal and anal fins with curved red stripes, and red pectoral fin. According to analysis of sequence variation within the cytochrome oxidase I locus, N. niassa is a well-distinct taxon related neither to the N. melanospilus species group nor to N. kirki, but clusters with very high support with a clade including N. guentheri, N. albimarginatus, N. korthausae, N. foerschi, N. cardinalis and N. kilomberoensis (subgenus Adiniops). Within this clade, the closest related species is N. kilomberoensis, known from Kilombero River floodplain, Tanzania, although with moderate support.