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 acanthuroid taxa (representing all six families) and seven outgroup taxa. The combined data set contained 1399 bp after removal of all ambiguously aligned positions. Examination of site saturation indicated that loop regions of both 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 within the Acanthuroidei, but it also differed in several areas. The putative sister group of Acanthuroidei, Drepane, was recovered within the suborder, and the sister group of the family Acanthuridae, Zanclus, was likewise recovered 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 monophyly of the Acanthuridae. A parametric bootstrap suggests the possibility that the paraphyly of Acanthuridae indicated by the molecular analyses is the result of long-branch attraction. The disagreement between molecular and morphological data on the relationships of the basal acanthuroids and its putative sister taxon is unresolved.