PHYLOGENETIC-RELATIONSHIPS OF THE WESTERN NORTH-AMERICAN PHOXININS (ACTINOPTERYGII, CYPRINIDAE) AS INFERRED FROM MITOCHONDRIAL 12S AND 16S RIBOSOMAL-RNA SEQUENCES

Parsimony analysis of the mitochondrial 12S and 16S rRNA sequences of North American phoxinin taxa indicated the existence of three major cl ades, the Western Clade, the Creek Chub Clade, and the Open Posterior Myodome Clade. The monophyletic Western Clade identified in this paper contained fewer taxa than that identified by previous authors. This c lade contained species restricted to drainages west of the Continental Divide, such as Gila, Acrocheilus, Relictus, Eremichthys, Siphateles, Ptychocheilus, Lavinia, and Orthodon, and the wide-ranging genus Phox inus found in eastern North America and Eurasia Within this Western Cl ade Phoxinus was the basal sister group. Gila was recognized as a mono phyletic group exclusive of Siphateles and Snyderichthys, clades tradi tionally recognized as subgenera of Gila. The genus Gila was most clos ely related to the genus Acrocheilus and together these formed the sis ter group to the genus Relictus. These relationships mere supported in dependent of weighting schemes used in analyses. Identification of Pho xinus as the basal sister taxon of the Western clade implies that othe r major clades of North American Phoxinins likely have Asian or Europe an relatives. (C) 1998 Academic Press.