Biological Journal of the Linnean Society, 2003, 80, 323–337. With 4 figures © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80, 323–337 323 Blackwell Science, LtdOxford, UKBIJBiological Journal of the Linnean Society0024-4066The Linnean Society of London, 2003? 2003 802 323337 Original Article PHYLOGENETIC RELATIONSHIPS OF NOTROPIS IN MEXICO S. SCHÖNHUTH and I. DOADRIO *Corresponding author. E-mail: mcns137@mncn.csic.es Phylogenetic relationships of Mexican minnows of the genus Notropis (Actinopterygii, Cyprinidae) SUSANA SCHÖNHUTH* and IGNACIO DOADRIO Museo Nacional de Ciencias Naturales. C.S.I.C., Dpto. Biodiversidad y Biología Evolutiva, José Gutiérrez Abascal 2, Madrid 28006, Spain Received 27 August 2002; accepted for publication 2 April 2003 We conducted phylogenetic analyses based on complete mitochondrial cytochrome b gene sequences among southern and central Mexican cyprinid species, included in the genera Notropis and Hybopsis. In addition 15 northern species of the genera Notropis and Hybopsis were included in the analyses in order to place the Mexican species into a larger phylogenetic framework. The phylogenetic relationships supported the existence of five major clades: (1) including species of the subgenus Alburnops of the genus Notropis plus N. shumardi; (2) species of the subgenus Notropis; (3) species of the genus Hybopsis; (4) species of the N. texanus + N. volucellus species group of the genus Notropis; (5) Mexican endemic species of the genus Notropis plus the genus Yuriria. Previous phylogenetic inferences based on morphological characters resolved the Mexican minnows analysed as N. sallaei, N. calientis, N. boucardi and Y. alta, non-monophyletic. According to our cytochrome b evidence all Mexican minnows of the genera Notropis and Yuriria formed a monophyletic group with respect to the northern species of the genera Notropis and Hybopsis. Within the Mexican clade, three well-supported clades were identified: the first included the closely related species N. moralesi and N. boucardi, which occur in three independent drainages of south Mexico; the second consisted of two different lineages, N. imeldae and an undescribed species of Notropis, inhabiting two independent drainages of south Mexico; the third comprised two central Mexican Notropis species (N. calientis and N. sallaei) and the Y. alta populations. Based on this study and pending a more extensive taxonomic revision of the genus Notropis, we adopt the conser- vative criterion of considering all Notropis species from southern and central Mexico examined, including Y. alta, as belonging to the genus Notropis. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80, 323–337. ADDITIONAL KEYWORDS: Bayesian inference – cyprinids – cytochrome b – Mexico – mitochondrial DNA – trans-Mexican volcanic belt. INTRODUCTION With close to 100 species, the genus Notropis s.l. is among the most species-rich genera of Nearctic fresh- water fishes. It occurs in rivers from Canada and Alaska to southern Mexico. The taxonomy and phylo- genetic relationships of the genus in the United States and Canada have been the subject of extensive research (Buth, 1979; Stein, Rogers & Cashner. 1985; Dimmick, 1987; Mayden, 1989, 1991; Coburn & Cav- ender, 1992; Warren, Burr & Grady, 1994; Simons & Mayden, 1999; Bielawski & Gold, 2001; Raley & Wood, 2001). Unfortunately, few studies have focused on Mexican species south of the Río Bravo. Notropis is currently represented in Mexico by at least 20 species (Burr & Mayden, 1981; Espinosa, Gaspar & Fuentes, 1993), but only the following five recognized species are distributed across central and southern Mexico: N. boucardi (Günther, 1868), N. sallaei (Günther, 1868), N. calientis Jordan & Sny- der, 1900, N. moralesi De-Buen, 1955 and N. imeldae Cortés, 1966. Taxonomy of these species has been con- troversial. For example, N. sallaei was included in eight different genera and 16 nominal species. Cher- noff & Miller (1981) considered it as a highly variable taxon ‘provisionally’ assigned to Notropis, which was followed by different authors (Chernoff & Miller, 1986; Espinosa et al., 1993), or it was considered as several subspecies (Vallejo de Aquino, 1988), while some authors consider it to be the only member of the