Morphological and molecular variability of the species complex of Actinostella flosculifera (Le Sueur, 1817) (Cnidaria: Actiniaria: Actiniidae) across the western and eastern Atlantic Ocean: are there cryptic species involved?

Based on a phylogenetic and morphological analysis of different populations of Actinostella flosculifera (Le Sueur, 1817) species complex throughout the Caribbean Sea, the Gulf of Mexico, and Brazil, and on the descriptions of Barragán et al . [1] from the Caribbean Sea and Ocaña (1994) from the Canary Islands (CI), as well as other studies in South America, we found that all samples of A. flosculifera on the east coast of America presented similar characteristics (both internal and external) and could not be distinguished from one another. Genetically, we could differentiate two subclades. The individuals of the CI presented holotrichs and an additional mesenteric cycle, indicating that reviewing new material for verification is necessary. Additionally, we document the second report of cinclides within the family Actiniidae. We recognize the need for further molecular studies to understand the evolutionary history of the A. flosculifera species complex, incorporating additional specimens from other locations, as well as sequences from other congeners, and using other molecular markers (e.g., with ultraconserved elements).