Genetic analysis reconstructs lamprey taxonomy
Lampreys are misunderstood species. There is a whole group of researchers passionate about studying and protecting them.
Lampreys are the oldest living fish and were present on Earth before dinosaurs and trees. Yet, relative to fish like trout and salmon, very little research has been done on this taxonomic group. Scientists at the U.S. Forest Service Rocky Mountain Research Station, along with Fisheries Biologists Doug Larson and Matt Helstab from Willamette National Forest Middle Fork Ranger District, set out to map the distributions of western river and brook lampreys in the Willamette River basin, in western Oregon.
Given the limited information on lamprey, their work quickly shifted towards identification. Lampreys are notoriously hard to identify down to the species level based on visual observation, because they lack key distinguishable features such as bones and jaws, and different species appear identical as larvae. They turned to genetic data but continued to encounter challenges. The researcher's use of DNA provided more accurate details and concrete evidence to renovate the lamprey taxonomic structure.
Historically, lamprey in North America and Eurasia have been classified in the same genera: Lampetra. DNA analysis showed that there are three distinct genera, one each in western America, eastern America, and Eurasia. Lamprey in America were described as three species: Pacific brook lamprey (Lampetra pacifica), western brook lamprey( Lampetra richardsoni), and western river lamprey (Lampetra ayresii). New research now proves that there are at least seven distinguishable species.
The team found that western brook lamprey and western river lamprey, both found in the Pacific Northwest, cannot be distinguished based on genetic information. Instead, these fish represent life history variants of a single species, with differences in adult morphology, migratory patterns and feeding behavior. The scientists have not only renovated lamprey’s taxonomic tree but uncovered unseen genetic diversity and provided key genetic information about these fish. These factors can support management of lampreys. Lampreys are filter feeders, improving water quality (with new evidence that they filter out pathogens), and play a key role in nutrient cycling among aquatic systems. Information on new species distinctions and local genetic diversity can help managers working in the Willamette River protect the diversity of lamprey populations unique to this river basin.