Geographic distribution of Phalloceros Eigenmann, 1907 (Cyprinodontiformes, Poeciliidae) in the Ilha Grande Bay Hydrographic Region, Rio de Janeiro, Brazil

A new study identifies five species of Phalloceros fish within the Ilha Grande Bay Hydrographic Region, Brazil—Phalloceros anisophallos, P. aspilos, P. enneaktinos, P. harpagos, and P. tupinamba—with two (P. harpagos and P. tupinamba) recorded for the first time in the area. The research expands the known geographic ranges of P. anisophallos and P. enneaktinos while revealing distinct morphological lineages based on female urogenital papilla structures, which influence species distribution patterns: sympatric occurrence is possible across different lineages, but allopatry is observed within the same lineage. The study analyzed 81 samples and provides a key for species identification, contributing to biodiversity documentation in this UNESCO-listed region.

Souto-Santos, I. C. d. A., Ferraro, G. A., Jennings, W. B., Vergara, G. L. d. S., & Buckup, P. A. (2019). Geographic distribution of Phalloceros Eigenmann, 1907 (Cyprinodontiformes, Poeciliidae) in the Ilha Grande Bay Hydrographic Region, Rio de Janeiro, Brazil. Check List, 15(1), 181–192. https://doi.org/10.15560/15.1.181