The osteology and relationship of Metaxytherium krahuletzi Depéret, 1895 (Mammalia: Sirenia)

Metaxytherium krahuletzi was a halitheriine dugongid distributed throughout the marine waters of the Central Paratethys, and probably other parts of Europe' during the Early Miocene (upper Eggenburgian and Ottnangian - early to middle Burdigalian). It was probably an ecological generalist that fed on the leaves and rhizomes of small and medium-sized benthic seagrasses. It appears to be the sister group and direct ancestor of all the other Old World (European, Mediterranean, and North African) Metaxytherium, though its relationship to New World species remains unclear. This study documents its morphology, stratigraphic and geographic distribution, and cladistic relationships, showing that it differs from its putative direct descendant M. medium only in characters of the skull, mandible, and possibly sternum that display significant and inadequately-sampled individual variation. Although the species M. krahuletzi is still considered valid, larger samples of this and related species are needed to demarcate more clearly the stages of evolution in this lineage' which evolved slowly in comparison with other sirenians.