A 40-year taxonomic enigma: multigene phylogeny resolves the polyphyly of <i>Plectranthias</i> (Perciformes: Anthiadidae) and supports a revised taxonomy

Abstract Anthiadidae, a family of shallow and deep-water reef-associated fishes, include about 250 species distributed widely from tropical to temperate regions, with the majority found in the tropical Indo-West Pacific (IWP). Despite their broad distribution, the phylogeny and taxonomy of this family remain unresolved, particularly at the generic level, due to challenges in sampling from deep-water zones. Plectranthias, the most species-rich genus, has been suspected of non-monophyly since its last revision over 40 years ago. In this study, we explore the phylogenetic relationships of anthiadids using a multigene dataset (one mitochondrial and four nuclear genes) from 103 specimens across 19 genera, with a focus on IWP Plectranthias. Our results confirm the polyphyly of Plectranthias, revealing seven distinct clades. Based on this new phylogenetic framework and morphological re-examinations, we propose a taxonomic revision, including the resurrection of the genera Pelontrus, Sayonara, Xenanthias, and Zalanthias, and the establishment of Aepysomanthias and Poroanthias Tang and Chen gen. nov. The revised taxonomy restricts Plectranthias to 20 currently recognized species.