Costa, 2009
Rivulus megaroni, a new killifish from the Xingu River drainage, southern Brazilian Amazon (Cyprinodontiformes: Rivulidae).Rivulus megaroni, new species, is described from the Xingu River drainage, southern Amazonas River basin, central Brazil. It is similar to other species of Melanorivulus endemic to the southern Amazonian tributaries of central Brazil by having a unique color pattern of flank in males, consisting of red marks arranged in a chevronlike pattern, in which the chevron vertex is placed on the ventral portion of the flank. The new species is distinguished from all other species sharing that color pattern by a combination of 34-36 scales in the longitudinal series, seven well-developed pelvic-fin rays, chevron marks of flank arranged as oblique bars, absence of red pigmentation on the tip of the lower jaw, a horizontal series of white spots on the dorsal portion of the caudal fin in females, and caudal fin pink in males.
Costa, W.J.E.M.
Ichthyological Exploration of Freshwaters, 20 (4): 365-370, 2009.