Filling the gaps: phylogeography of the self-fertilizing Kryptolebias species (Cyprinodontiformes: Rivulidae) along South American mangroves.

Mangrove killifishes of the genus Kryptolebias have been historically classified as rare because of their small size and cryptic nature. Major gaps in distribution knowledge across mangrove areas, particularly in South America, challenge the understanding of the taxonomic status, biogeographical patterns and genetic structuring of the lineages composing the self-fertilizing 'Kryptolebias marmoratus species complex'. Here, we combined a literature survey, fieldwork, and molecular data to fill major gaps of information about mangrove killifishes distribution across western Atlantic mangroves. We found that selfing mangrove killifishes are ubiquitously distributed across the Caribbean, Central, and South American mangroves and report 14 new locations in South America, extending the range of both the 'Central clade' and 'Southern clade' lineages which overlap in the Amazon. Although substantial genetic differences were found between clades, we also found further genetic structuring within clades, with populations in Central America, North, and Northeast Brazil generally showing higher levels of genetic diversity compared to the clonal ones in southeast Brazil. We discuss the taxonomic status and update the geographical distribution of the Central and Southern clades, as well as potential dispersal routes and biogeographical barriers influencing the distribution of the selfing mangrove killifishes in the western Atlantic mangroves. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.