Phylogenomic Analysis Confirms the Need for a Taxonomic Revision of the Pikeminnows (Teleostei: Ptychocheilus)

Authors: Derek Houston

Year: 2023

Abstract

Taxonomy is important for better understanding the natural world, classifying organisms for effective scientific communication, and for operational conservation of imperiled species. The pikeminnows belong to a genus (Ptychocheilus) comprising four species that are geographically distributed in western North America. Their taxonomic status has been called into question based on phylogenies wherein the genus is not monophyletic. However, a corresponding taxonomic change has not yet been made. We revisited this issue using DNA sequence data from ultraconserved genomic elements (UCEs). Our results support the hypothesis of a non-monophyletic (i.e., polyphyletic) genus Ptychocheilus. The Sacramento pikeminnow (P. grandis) appears to be a monotypic genus, and the desert dace (E. acros) more recently shared a common ancestor with the northern pikeminnow (P. oregonensis) and the Umpqua pikeminnow (P. umpquae) than did the Colorado pikeminnow (P. lucius). Thus, a taxonomic revision of the genus is needed. Following the Law of Priority in taxonomy, the northern pikeminnow should retain the genus name Ptychocheilus, as should the Umpqua pikeminnow, its sister species. The Colorado pikeminnow and Sacramento pikeminnow need to be assigned to new genera.