Molecular phylogenies confirm the presence of two cryptic Hemimycale species in the Mediterranean and reveal the polyphyly of the genera Crella and Hemimycale (Demospongiae: Poecilosclerida)

摘要

BackgroundSponges are particularly prone to hiding cryptic species as their paradigmatic plasticity often favors species phenotypic convergence as a result of adaptation to similar habitat conditions. Hemimycale is a sponge genus (Family Hymedesmiidae, Order Poecilosclerida) with four formally described species, from which only Hemimycale columella has been recorded in the Atlanto-Mediterranean basin, on shallow to 80 m deep bottoms. Contrasting biological features between shallow and deep individuals of Hemimycale columella suggested larger genetic differences than those expected between sponge populations. To assess whether shallow and deep populations indeed belong to different species, we performed a phylogenetic study of Hemimycale columella across the Mediterranean. We also included other Hemimycale and Crella species from the Red Sea, with the additional aim of clarifying the relationships of the genus Hemimycale.