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Sea chubs of the family Kyphosidae are major consumers of macroalgae on both temperate and tropical reefs, where they can comprise a significant proportion of fish biomass. However, the relationships and taxonomic status of sea chubs (including the junior synonyms Hermosilla, Kyphosus, Neoscorpis and Sectator) worldwide have long been problematical due to perceived lack of character differentiation, complicating ecological assessment. More recently, the situation has been further complicated by publication of conflicting taxonomic treatments. Here, we resolve the relationships, taxonomy and distribution of all known species of sea chubs through a combined analysis of partial fragments from mitochondrial markers (12s, 16s, cytb, tRNA -Pro, -Phe, -Thr and -Val) and three nuclear markers (rag1, rag2, tmo4c4). These new results provide independent evidence for the presence of several junior synonyms among Atlantic and Indo-Pacific taxa, demonstrating that several sea chub species are more widespread than previously thought. In particular, our results can reject the hypothesis of endemic species in the Atlantic Ocean. At a higher taxonomic level, our results shed light on the relationships between Girellidae, Kuhliidae, Kyphosidae, Microcanthidae, Oplegnathidae and Scorpididae, with Scorpididae resolved as the sister group to Kyphosidae., (Copyright © 2016 Elsevier Inc. All rights reserved.)

A molecular phylogenetic analysis with complete species sampling of the family Kyphosidae revealed several discrepancies with the current taxonomy. We thus undertook a complete taxonomic revision of all kyphosid genera, i.e. Kyphosus Lacepède, 1801, and the monotypic Hermosilla Jenkins and Evermann, 1889, Sectator Jordan and Evermann, 1903 and Neoscorpis Smith, 1931. Species delimitation was determined on the basis of congruence between (a) monophyletic groupings in the molecular phylogeny, and (b) clusters of morphological variation in type material. Twelve species are supported and redescribed. Both Hermosilla and Sectator are considered junior synonyms of Kyphosus. Kyphosus azureus (Jenkins & Evermann, 1889) and K. ocyurus (Jordan & Gilbert, 1882) are redescribed accordingly. We designate a neotype for Kyphosus cornelii (Whitley, 1944), as the original material is lost, and new material was collected at the type locality for this study to facilitate comparison with other species of Kyphosus. Kyphosus sandwicensis (sensu Sauvage, 1880) was found to be a junior synonym of K. elegans (Peters, 1869). Kyphosus incisor (Cuvier in Cuvier & Valenciennes, 1831) and K. analogus (Gill, 1862) are considered junior synonyms of K. vaigiensis (Quoy & Gaimard, 1825). Kyphosus gallveii (Cunningham, 1910), K. pacificus Sakai and Nakabo, 2004 and K. lutescens (Jordan & Gilbert, 1882) are all considered junior synonyms of K. sectatrix (Linnaeus, 1758). One of the two syntype specimens of K. sectatrix was identified as the holotype of Pimelepterus bosquii (Lacepède, 1802), and proved to be a specimen of K. bigibbus Lacepède, 1801. This specimen is re-assigned as a non-type of K. bigibbus. Full re-descriptions of the following valid species are presented: K. bigibbus, K. cinerascens (Forsskål, 1775), K. cornelii, K. elegans, K. hawaiiensis Sakai and Nakabo, 2004, K. gladius Knudsen and Clements, 2013, K. sydneyanus (Günther, 1886) and K. vaigiensis, together with a key to the family. The distribution of Kyphosus species is reconsidered based on our taxonomic revision, indicating that four species (K. bigibbus, K. cinerascens, K. sectatrix and K. vaigiensis) occur in both the Atlantic and Indo-Pacific regions.