Extreme homogeneity and low genetic diversity in Kryptolebias ocellatus from south-eastern Brazil suggest a recent foundation for this androdioecious fish population.

This study documents unexpectedly low levels of intra and interpopulation genetic diversity in Kryptolebias ocellatus, an androdioecious and predominantly self-fertilizing killifish from south-eastern Brazil. This finding generally is inconsistent with the established opinion that the K. ocellatus and K. marmoratus clade originated in this geographic region and later dispersed northward into the Caribbean.