This project involves a higher level phylogeny analysis of the Anguilliformes based on head musculo-skeletal morphology. The structural detail of head features of fifteen families′ representative of the Anguilliformes are compared, as well as some outgroups from the Eurypharyngidae and Notacanthidae. This research focuses on the head bones and muscles as important elements of the feeding and respiration apparatus. The head anatomy (bones and relevant muscles) and their integration in the skull will be considered in a context of evolutionary specializations and trends in Anguilliformes, especially focusing on trophic specializations. The obtained morphological characters will also be used to perform a cladistic analysis of this group.