5: Trout and Char: Taxonomy, Systematics, and Phylogeography
Andrew R. Whiteley, Brooke E. Penaluna, Eric B. Taylor, Steve Weiss, Alicia Abadia-Cardoso, Daniel Gomez-Uchida, Itsuro Koizumi, and Patrick Trotter
The geographic domain of trout and char is vast. Their native distributions span all continents in the Northern Hemisphere, including the region of North Africa. Most species of trout and char depend entirely on freshwater habitats, and many occur throughout watersheds from headwaters to estuaries. Current taxonomy and within-species patterns of genetic variability in trout and char are the result of complex reorganization of these freshwater habitats since the Eocene, or approximately over the past 60 million years (Crête-Lafrenière et al. 2012; Penaluna et al. 2016; Lecaudey et al. 2018). The family Salmonidae contains three subfamilies: Thymallinae (grayling), Coregoninae (whitefish, cisco, and Inconnu Stenodus leucichthys), and Salmoninae (char, trout, huchen, taimen, lenok, and salmon) (Kendall and Behnke 1984; Stearley and Smith 1993; Crespi and Fulton 2004; Crête-Lafrenière et al. 2012). In this chapter, we focus on trout and char in the genera Oncorhynchus, Salvelinus, and Salmo, as listed in Table 1 (along with common names from five languages). We note that we excluded the genera Brachymystax, Hucho, and Parahucho from consideration as they are generally not considered trout or char, but we do include these taxa in our attempt to quantify the number of species within the subfamily Salmoninae (Box 1).