Frontiers in Marine Science (Nov 2015)
More than archetypal coral-reef fishes: Revision and relationships of the Acanthuroidei based on adult and larval morphology
Abstract
Acanthuroid fishes are often considered archetyal coral-reef fishes. We use characters of both larvae and adults to redefine the Acanthuroidei to include the traditional acanthuroid families (Acanthuridae, Ephippidae, Luvaridae, Scatophagidae, Siganidae, Zanclidae) and several taxa usually placed within the Percoidei (Antigonia, Chaetodontidae, Drepaneidae, Leiognathidae, Lobotidae, Pomacanthidae). These taxa share a specialised tooth ontogeny. Based on larval morphology (particularly head spination, sculpting on the skull, early development of posteriorly-placed pelvic fins, pigmentation, and body shape) and adult morphology (dorsal gill-arches) the Lobotidae is newly diagnosed to include the genera Lobotes, Datnioides and Hapalogenys. These three genera have traditionally been placed in the families Lobotidae, Datnioididae and Haemulidae, respectively, although Hapalogenys was sometimes placed in a separate Hapalogenyidae. Three-item analysis shows that Lobotidae is the sister group of the remaining acanthuroids. Antigonia and Leiognathidae are nested within a clade consisting of the traditional acanthuroids on the basis of a number of synapomorphies, including a single postcleithrum, five or fewer branchiostegal rays, absence of the interarcual cartilage and larval morphology. The sister group of the Acanthuroidei remains unclear. We compare this phylogeny of the revised Acanthuroidei with recent phylogenies based exclusively on genetic data. Although the different gene-based phylogenies agree on some aspects, they disagree on others. Similarly, the morphology-based phylogeny has areas of both agreement and disagreement with the gene-based phylogenies. Areas of agreement (where relevant taxa were included in the analysis) include: removal of Hapalogenys from Haemulidae; inclusion of Lobotes, Datnioides and Hapalogenys in Lobotidae; Lobotidae, Caproidae and Leiognathidae related to at least some of the acanthuroid taxa as defined here; Luvaridae and Zanclidae included in Acanthuroidei. The redefined Acanthuroidei includes species that live in a wide variety of habitats: coral reefs, epipelagic oceans, muddy and sandy bottoms, outer continental shelves and slopes, estuaries, mangroves and even fresh water.
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