Comprehensive Phylogenetic Analysis of All Species of Swordtails and Platies (Pisces: Genus Xiphophorus) Uncovers a Hybrid Origin of a Swordtail Fish, Xiphophorus Monticolus, and Demonstrates that the Sexually Selected Sword Originated in the Ancestral Lineage of the Genus, But was Lost Again Secondarily

by Ji Hyoun Kang, Manfred Schartl, Ronald B. Walter, Axel Meyer · 2015