Multigene phylogeny of cyprinodontiform fishes suggests continental radiations and a rogue taxon position of Pantanodon

Abstract

We studied phylogenetic relationships among major clades in the tooth carps (Cyprinodontiformes) based on a concatenated DNA sequence alignment of two mitochondrial and three nuclear gene segments, totalling 2553 bp, in 66 ingroup terminals. The inferred tree supports monophyly of the major tooth carp subgroups, aplocheiloids and cyprinodontoids, and of several aplocheiloid subclades corresponding to the well-established families (Aplocheilidae, Nothobranchiidae, Rivulidae), each of which is restricted to major continental settings (India-Madagascar, Africa, South America). Contrary to previous molecular studies, our tree supports a sister-group relationship of the aplocheilids and nothobranchiids, rather than a nothobranchiid-rivulid clade. Within cyprinodontoids, the phylogeny matched more closely continent-scale distribution than current classification, suggesting that the delimitation of the families Cyprinodontidae, Poeciliidae, and Valenciidae is in need of revision. The East African Pantanodon stuhlmanni did not show close relationships with any other taxon in our analysis, suggesting that the phylogenetic position and classification of this rogue taxon is in need of further study.