Inconspicuous genetic and morphological patterns challenge the taxonomic status of endemic species Bodianus insularis (Labridae)

Abstract

Bodianus constitutes a marine fish group of particular interest due to its trophic interactions with reef environments. Knowledge of phylogenetic relationships of this genus have been improved by shared advances of classical and genetic approaches. However, some of its species have yet to be compared regarding its genetic patterns. Morphological variations in body shape and color patterns during the course of ontogenetic development, in addition to recurring sex reversal in species of this genus, make its taxonomy challenging. In the Atlantic Ocean five species have been described: Bodianus scrofa and Bodianus speciosus (Eastern Atlantic), Bodianus rufus (Western Atlantic), Bodianus pulchellus (Western Atlantic and Eastern Atlantic Islands) and Bodianus insularis (Mid-Atlantic islands). The phylogenetic relationships of the last species could not be resolved using genetic analyses. With a very restrict geographic distribution, B. insularis deserves high attention regarding its taxonomic and evolutionary aspects. Here, we use mitochondrial DNA sequences (COI and 16S rRNA) and nuclear analyses (rhodopsin) to assess the genetic divergence of B. insularis in relation to other Atlantic species and clarify its phylogenetic relationships. Bodianus pulchellus and B. insularis were not genetically distinct and are grouped with B. rufus, forming a sister clade of B. speciosus, while B. scrofa is more related to Pacific species. DNA-based and morphological traits are very similar between B. insularis and B. pulchellus, whose most obvious difference is their color pattern. The actual reinterpretation of ecological and biogeographic contexts allows to suggest that B. insularis is most likely a synonym of B. pulchellus, constituting a population enclave of this species.