By Sunyeong Oh, Brigham Young University
Five of 64 recognized species of freshwater sculpins (Cottus) reside in the Upper Snake River Plain of Southeastern Idaho and Western Wyoming. These five species belong to three phylogenetic lineages, Cottus beldingii (including Cottus leiopomus and C. greenei), Cottus confusus, and Cottus bairdii. The complex tectonic/hydrological history of this region appears to have favored independent invasions Candidate sources of invasion include the Lahontan Basin, the Columbia River system, the Bonneville Colorado River Basins and the Upper Missouri River.
The C. beldingii lineage appears to have entered the Upper Snake River prior to the isolation of the Lahontan Basin from the Upper Snake River system. It likely dispersed into the Wood River and the Lost River drainages on the northern edge of the Snake River Plain via the Snake River.
C. confusus, found in the Lower and Middle Snake River, is also present in the Lost River streamsand appears to have entered through the Salmon River, sometime after the isolation of the Lahontan Basin. The third lineage, C. bairdii, appears to have originated in Atlantic Basin streams and may have invaded the Upper Snake River Plain through stream captures from the Upper Missouri River Basin after isolation of the Lahontan Basin. Both C. beldingii and C. bairdii may have dispersed into the Bonneville and Colorado River basins more recently.
We have examined mitochondrial DNA and are now validating nuclear DNA markers developed through RNA isolation and cDNA sequencing on a next generation sequencing platform. We anticipate that phylogenetic analyses of DNA sequence data will allow us to determine the actual sources of cottids in the Upper Snake River Plain. We are also examining the phylogenetic associations among cottids in the adjacent Lahontan, Bonneville, Colorado River, Lower Snake River/Columbia River, and Upper Missouri River basins. These relationships are critical for testing the hypothesized dispersal patterns.
Part of the July 2014 (PDF) issue of Lateral Lines.