DNA phylogeny supports revised classification of Salmothymus obtusirostris

Abstract

Salmothymus obtusirostris (soft-muzzled trout) is endemic to the South Adriatic drainage. Owing to its unusual appearance, which resembles both trout and grayling, it has been initially classified as a separate genus. However, this classification is ambiguous and has never been firmly established. We have studied mtDNA (control region and cytochrome b gene) and nuclear DNA (a part of LDH C*1 gene) variation between soft-muzzled trout from the upper part of the River Neretva, Bosnia and Herzegovina, and other salmonid representatives in order to examine how the current classification is congruent with molecular data. On the basis of sequence identity of mtDNA control region among several genera (i.e. Salmo, Oncorhynchus, Salvelinus, Acantholingua, Brachymystax, Thymallus and Coregonus) a close relationship between Salmothymus, Salmo and Acantholingua was established. Phylogenetic analysis on a combined data set of mitochondrial and nuclear DNA, supported by 100% bootstraping, indicated that S. obtusirostris and A. ohridana are sister taxa which exhibit a closer relationship to S. trutta than to S. salar. This finding refutes the current classification, which recognizes S. obtusirostris as separate genus, and instead suggests its reclassification on the species level as Salmo obtusirostris. © 2002 The Linnean Society of London.