FINE-SCALE GENETIC STRUCTURING AMONG MEDITERRANEAN PARAZOANTHUS AXINELLAE (SCHMIDT, 1862) SPECIES COMPLEX POPULATIONS DISCLOSED BY 2BRAD

Two morphotypes of the Mediterranean zoanthid Parazoanthus axinellae (Schmidt, 1862) are found in the Mediterranean Sea: ‘Slender’ and ‘Stocky’, which differ in size, color, and substrate preference. We used 2bRAD-Seq to get genome‐wide genotyped single nucleotide polymorphisms to study the genetic differentiation between ‘Slender’ and ‘Stocky’ morphs, as well as their population structure. 101 specimens of P. axinellae were sampled and genotyped from locations along the Italian coastline. A marked and consistent differentiation between the morphs was observed. The widely distributed ‘Slender’ morph showed higher population admixture, whereas populations of the 'Stocky' morph, found only in the north-western Mediterranean, showed higher regional genetic partitioning.