| The bluehead sucker (Catostomus discobolus) is a fish whose distribution and
taxonomic classification are ambiguous; populations occupying the Snake River
watershed and Bonneville basin are proposed to be a distinct species, the green sucker
(Pantosteus virescens). Here, I applied genetic and morphometric techniques to assess
diversity in bluehead suckers across watersheds. Additionally, I compared bluehead
suckers with the closely-related mountain sucker (Catostomus platyrhynchus) across
their sympatric range. Analysis of mitochondrial DNA revealed divergence of bluehead
suckers across watershed boundaries and suggests historical hybridization between
bluehead and mountain suckers. Bluehead and mountain suckers formed distinct
clusters across watersheds by single nucleotide polymorphism data. Morphometric
analyses largely paralleled results from genetic data. All analyses support the
distinctiveness of bluehead suckers from the Snake River and Bonneville basin from
those in the Colorado River watershed. This study provides multifaceted insight into the
distinguishing characteristics and diversity of the riverine sucker species complex. |