[[Genus Simpsonichthys ^ZBK ]]

Simpsonichthys Carvalho ^ZBK is a speciose clade of South American killifishes, with a total of 40 species inhabiting seasonal pools of central, northeastern and southeastern Brazil and northern Paraguay (Costa, 1998, 2003). A subclade, here called S. constanciae species group, is diagnosed by the lateral position of eye on the head and by a derived arrangement of supraorbital neuromasts (Costa, 2003), and is endemic to the coastal river basins of northeastern and southeastern Brazil. It comprises S. constanciae (Myers), S. bokermanni (de Carvalho and da Cruz), S. perpendicularis Costa, Nielsen and De Luca ^ZBK, and S. rosaceus Costa, Nielsen and De Luca ^ZBK. A fifth species of this assemblage is herein described.