Abstract
ABSTRACT Metaxytherium subapenninum was a halitheriine dugongid distributed along the northwestern coasts of the Mediterranean Basin during the early and late Pliocene. It represents the latest sirenian species of the Mediterranean Basin, the latest Metaxytherium species in the world, and also the latest species belonging to the paraphyletic subfamily Halitheriinae. We review M. subapenninum in the light of new discoveries, including its stratigraphic and geographic distribution, osteology, paleoecology, and relationships. M. subapenninum represents a more derived stage of evolution in comparison with the earlier Metaxytherium species. It is characterized in particular by an increase in body size, an increase in tusk size, and a dorsal broadening of the nasal process of the premaxilla. Its variation in tusk size does not appear to represent sexual dimorphism as in the modern Dugong, but instead progressive intraspecific evolution of larger tusks as a feeding adaptation convergent on that of derived dugongines. It was a relict species limited to the Mediterranean Basin, and responded to long-term climatic cooling by an increase in body size and by an increase in tusk size and rostral reinforcement in order to obtain a more nutritious diet richer in rhizomes.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
