A <i>tenuis</i> relationship: traditional taxonomy obscures systematics and biogeography of the ‘<i>Acropora tenuis</i>’ (Scleractinia: Acroporidae) species complex

Abstract Molecular phylogenetics has fundamentally altered our understanding of the taxonomy, systematics and biogeography corals. Recently developed phylogenomic techniques have started to resolve species-level relationships in diverse ecologically important genus Acropora, providing a path taxonomy this notoriously problematic group. We used targeted capture dataset (2032 loci) investigate systematic within an Acropora clade containing putatively widespread species tenuis its relatives. Using maximum likelihood phylogenies genetic clustering single nucleotide polymorphisms from specimens, including topotypes, collected across Indo-Pacific, we show ≥ 11 distinct lineages clade, only four which correspond currently accepted species. Based on molecular, morphological geographical evidence, describe two new species; rongoi n. sp. tenuissima remove five additional nominal synonymy. Systematic revealed by molecular phylogeny are incongruent with traditional demonstrate that characters traditionally delineate boundaries infer evolutionary history homoplasies. Furthermore, much smaller ranges and, consequently, population sizes than thought, finding profound implications for conservation management reef