Filling in another piece of the puzzle: Using Integrative Taxonomy to establish yet another new species of Hediste (Annelida, Polychaeta, Nereididae)

One of the most prevalent autochthonous polychaete taxa in the European Atlantic and Mediterranean seas is the genus Hediste (Nereididae, Polychaeta, Annelida). Its species provide food for aquatic life, such as fish and crustaceans, playing significant ecological roles in trophic webs. Until 2022, only the species Hediste diversicolor was referenced for Atlantic and Mediterranean waters; nonetheless, it is a cryptic species, in which Hediste pontii in the Adriatic Sea, and Hediste astae in the Aegean, Black, Caspian, and Baltic seas have recently been established. In this paper, we propose a new species of polychaete, Hediste sinesimplex sp. nov. for the Western Mediterranean, Baltic and Eastern North seas, based on an integrative approach, focusing on traditional taxonomy and DNA barcoding analysis. In addition to the morphological description, we have also included 3D models of this new species to exemplify the use of this technique for in-depth morphological description.