The phylogenetic relationships of the suborder Acanthuroidei (Teleostei : Perciformes) based on molecular and morphological evidence

Fragments of 12S and 16S mitochondrial DNA genes were sequenced for 14 acan thuroid taxa (representing all six families) and seven outgroup taxa. The c ombined data set contained 1399 bp after removal of all ambiguously aligned positions. Examination of site saturation indicated that loop regions of b oth genes are saturated for transitions, which led to a weighted parsimony analysis of the data set. The resulting tree topology generally agreed with previous morphological hypotheses, most notably placing the Luvaridae with in the Acanthuroidei, but it also differed in several areas. The putative s ister group of Acanthuroidei, Drepane, was recovered within the suborder, a nd the sister group of the family Acanthuridae, Zanclus, was likewise recov ered within the family. Morphological characters were included to produce a combined data set of 1585 characters for 14 acanthuroid taxa and a single outgroup taxon. An analysis of the same 15 taxa was performed with only the DNA data for comparison. The total-evidence analysis supports the monophyl y of the Acanthuridae. A parametric bootstrap suggests the possibility that the paraphyly of Acanthuridae indicated by the molecular analyses is the r esult of long-branch attraction, The disagreement between molecular and mor phological data on the relationships of the basal acanthuroids and its puta tive sister taxon is unresolved. (C) 1999 Academic Press.