Molecular and morphological identification of polychaetes from the genus Marphysa from two Portuguese coastal systems

Henri Ringeard

In order to clarify the uncertainty about the presence of Marphysa sanguinea on the Portuguese coasts, the different morphological points which are characteristic of the genus have been observed and described for specimens collected in the Sado estuary and in the Ria Formosa. Their DNA has been extracted and regions from the, cytochrome oxidase subunit 1, COI and 16S ribosomal RNA genes have been amplified via PCR using either primers from the literature (ACOIAF/ COIEU-R for COI , Zanol and al., 2010) or newly designed. The differences in jaw apparatus, chaetae and number of gill filaments combined with the results of the phylogenetic study allow us to state that our specimens do not belong to Marphysa sanguinea. Following the discovery, in January 2020, of two new species belonging to Marphysa genus in the gulf of Cadiz, a region close to one of our sample areas, we also compared our specimens to Marphysa gaditana, one of these newly described species. Due to the few differences observed and the phylogenetic tree obtained, we suggest that the individuals of the genus Marphysa collected in the two Portuguese sites constitute a new species, hypothesis that needs further confirmation.