An integrative study of Anemonia viridis (Forsskål, 1775) and Aiptasia couchii (Cocks, 1851) (Cnidaria: Anthozoa) from the North Adriatic Sea

Although the biometric investigation of the cnidome represents an essential diagnostic feature to successfully identify cnidarian species, further efforts are needed to fully characterize eventual differences. Important model actiniarians, such Anemonia viridis and Aiptasia spp., are commonly used for scientific purposes; however, their identification is often difficult, and the description of their cnidome is, therefore, essential. To contribute to this necessity, specimens of Anemonia viridis and Aiptasia couchii from the North Adriatic Sea were collected to acquire data (i.e. length, width, size range, length/width ratio) about cnidae from different tissues (i.e. column, tentacles, actinopharynx, mesenteries, and acrorhagi/acontia). Four types of cnidae were observed in each species. A. viridis shows microbasic b-mastigophores, microbasic p-mastigophores, holotrichous isorhizas, and spirocysts, whereas A. couchii harbored basitrichs, microbasic p-mastigophore, microbasic p-amastigophore and spirocysts. Molecular and phylogenetic analyses were also performed using three mitochondrial markers to confirm the correct classification of the specimens here analysed.