The Osteology and Phylogenetic Relationships of the Blackfin Tuna, Thunnus Atlanticus (Lesson)

Comparisons with five other species of the genus Thunnus were made to determine the relationships and phylogenetic position of T. atlanticus and its correct taxonomic identity. From osteological evidence, T. atlanticus is intermediate with T. sibi and T. albacares and is slightly closer to the latter. The splitting of the genus Thunnus as proposed in the past by various authors is osteologically unsubstantiated in view of the compactness of the group formed by the six species of Thunnus and their closer relationships to each other than to any of the neighboring genera (Katsuwonus, Euthynnus, Sarda) with which Thunnus was compared. It is therefore suggested that the names Parathunnus, Neothunnus and Germo be incorporated with the genus Thunnus.