Phylogenetic uncertainty in ectoparasitic fish (Characiformes: Distichodontidae)

Claire McKay Flynn, Fordham University


The family Distichodontidae, which falls under the order Characiformes, contains a unique grouping of ectoparasitic fish species. Previous work has been conducted to determine the evolutionary relationships and divergence times of the distichodontids, with some uncertainty. This study utilizes sequence data of three mitochondrial loci (Cox1, Cytb, and Nd2) from distichodontid fishes, incorporating a greater number of species, and more individuals per species, than have been previously analyzed. A maximum likelihood analysis revealed similar topology to previous studies, though the grouping of the genera Ichthyborus and Hemistichodus as sister taxa was not supported. Divergence time estimation using a strict molecular clock model dated the divergence of ectoparasitic species to ca. 25 Ma (95% HPD: 16.2–34.6), during the Oligocene epoch. By reconstructing the ancestral state of fin-biting behavior, it was found that this behavior has evolved twice within this lineage of fishes (once in the MRCA of Ichthyborus and once in the MRCA of Belonophago, Phago, and Eugnathichthys), and subsequently lost in M. bashforddeani.

Subject Area

Ecology|Genetics|Evolution and Development

Recommended Citation

Flynn, Claire McKay, "Phylogenetic uncertainty in ectoparasitic fish (Characiformes: Distichodontidae)" (2015). ETD Collection for Fordham University. AAI1601368.