Biological Journal of the Linnean Society, 2002, 77, 399–411. With 6 figures © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 77, 399–411 399 Blackwell Science, LtdOxford, UKBIJBiological Journal of the Linnean Society0024-4066The Linnean Society of London, 2002 77 Original Article MOLECULAR PHYLOGENY OF SALMOTHYMUS OBTUSIROSTRIS A. SNOJ ET AL. *Corresponding author. E-mail: ales.snoj@bfro.uni-lj.si DNA phylogeny supports revised classification of Salmothymus obtusirostris ALES ˇ SNOJ 1 *, ENVER MELKIC ˇ 1 , SIMONA SUS ˇ NIK 2 , SAMIR MUHAMEDAGIC ´ 3 and PETER DOVC ˇ 1 1 University of Ljubljana, Biotechnical Faculty, Department of Animal Science, Groblje 3, 1230 Dom˘ zale, Slovenia 2 Agricultural Institute of Slovenia, Hacquetova 17, 1000 Ljubljana, Slovenia 3 University of Sarajevo, Faculty of Agriculture, Zmaja od Bosne 8, 71000 Sarajevo, Bosnia and Herzegovina Received 10 May 2002; accepted for publication 19 August 2002 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 Core- gonus) 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, Biological Journal of the Linnean Society, 2002, 77, 399–411. ADDITIONAL KEYWORDS: Acantholingua – archaic trout – brown trout – evolution – River Neretva – Salmo – soft-muzzled trout – taxonomy. INTRODUCTION The classification of the Salmonidae family is only partially established and the general consensus regarding the taxonomic status, recently confirmed by molecular data analyses (Oakley & Phillips, 1999; Shed’ko, 2002), has been reached only for well-studied genera (i.e. Oncorhynchus, Salmo, Salvelinus, Brachy- mystax and Hucho; Phillips & Oakley, 1997). Other genera, especially those inhabiting remote places in Asia and the Balkan Peninsula (i.e. Platysalmo, Acan- tholingua, Salmothymus), have been poorly studied and the available data are limited. This makes their classification and phylogenetic positions unclear (Stearley & Smith, 1993; Shed’ko et al., 1996; Oakley & Phillips, 1999; Osinov, 1999; Osinov & Lebedev, 2000). Salmothymus obtusirosrtis Heckel, 1851 (Crivelli, 1996; Kottelat, 1997) is certainly one of the most intriguing genera whose classification has been con- troversial since the pioneering studies on systematics of Balkan salmonids in the mid nineteenth century, up to modern times. S. obtusirostris is characterized by its striking similarity in appearance to both trout and grayling (Fig. 1). It is morphologically primitive and Downloaded from https://academic.oup.com/biolinnean/article/77/3/399/2639703 by guest on 05 June 2022