A multi-locus timetree of surgeonfishes (Acanthuridae, Percomorpha), with revised family taxonomy

We present the most comprehensive time-calibrated, species-level hypothesis of the timing of Acanthuridae (surgeonfishes and allies) evolution based on 76% of the extant diversity and nine genes. We recover two major acanthurid clades, Nasinae and Acanthurinae, and infer a much more recent Nasinae crown age (17 Ma) compared to a previous dating study for Naso. The Acanthurinae represent an older group that originated similar to 42 Ma, with most diversification occurring since the Early Miocene (beginning similar to 21 Ma). Our results strongly support a paraphyletic Acanthurus and Ctenochaetus, with multiple analyses recovering a clade grouping Ctenochaetus, A. nubilus and A. pyroferus. Contrary to previous studies, we also provide strong evidence that thick-walled, gizzard-like stomachs evolved only once within Acanthurus and that this morphology has a common origin in Acanthurus and Ctenochaetus. Based on our molecular analyses, in conjunction with the large body of morphological evidence, we recommend dissolving the genus Ctenochaetus into the genus Acanthurus. (C) 2013 Elsevier Inc. All rights reserved.