Dismantling the Phalloceros harpagos species complex (Teleostei: Poeciliidae): description of a new species from Brazilian highlands based on morphological and molecular evidence

Abstract

A new species of Phalloceros is described from the upper rio Paraná, the upper rio Paraíba do Sul, and headwaters of coastal rivers in southeastern Brazil. This species is distinguished from congeners by characters of both male and female genitalia, dorsal fin-ray counts, dorsal-profile shape, and pigmentation and position of the vertically elongated dark spot on the flanks. The species has been misidentified in the literature as P. harpagos. Our DNA sequence analysis of specimens from the type-locality has clarified that P. harpagos is restricted to drainages on the right bank of the middle Paraíba do Sul and to coastal drainages in the metropolitan region of Rio de Janeiro. The new species differs from P. harpagos by a flattened, hood-like projection of skin located between the anus and the urogenital papilla in most females, and by a rounded lamellar flap on the distal margin of both gonopodial appendices in small mature males (< 21.2 mm SL). Mitochondrial CO1 gene analysis revealed a 6% genetic divergence between the new species and P. harpagos, providing strong support for the distinctiveness of this new species.