Phylogeography of Cottids in the Lost River Streams of Idaho

The Snake River system appears to be an important center of diversification for many native fishes in the interior of western North America.  Three phylogenetic lineages of cottids, Cottus beldingii (including Cottus leiopomus), Cottus confusus, and Cottus bairdii, reflect this relationship.  Based on mtDNA, Cottus beldingii and its associated species may have entered the Wood River in the late Pliocene, forming Cottus leiopomus.  Later, Cottus beldingii in the Snake River were isolated from those in the Lahontan Basin by the draining of Lake Idaho.  The Upper Snake River Cottus beldingii invaded the Lost River streams during the Pleistocene, possibly through connections with the Upper Snake River during glacial maxima.  Cottus confusus appears to have entered the Lost River streams through headwater transfer from the Salmon River Basin.  Cottus bairdii may have gained access to the Upper Snake River Plain through stream capture events from the Upper Missouri River system as the Yellowstone Hot Spot moved progressively to the East-Northeast. Mitochondrial DNA evidence suggests that a second wave of invasions of a Cottus bairdii -like fish is currently underway in some of the eastern Lost River streams.  We present an examination of these hypothesized relationships using nuclear DNA sequencing.