Calabria

The winning specimen belongs to an individual of Metaxytherium serresii, an extinct species of sirenian related to the modern dugong. The most important finds of this species worldwide , both in quantity and completeness, come from the late Miocene outcrops of Cessaniti, in the province of Vibo Valentia.

Analysis of numerous cranial and mandibular remains has confirmed that M. serresii represents a chronospecies, that is, a species placed within an evolutionary lineage made up of a succession of populations with similar adaptive trends, distinguished into separate species on the basis of gradual changes accumulated over time. This lineage begins with Metaxytherium krahuletzi (Burdigalian, 20-16 Ma), passing to Metaxytherium medium (Langhian-LateTortonian, 16-8 Ma), followed by Metaxytherium serresii (Late Tortonian-basal Zanclean, 8-5,3 Ma), from which Metaxytherium subapenninumderives, the last representative species of sirenians in the Mediterranean, becoming extinct in the Piacenzian (around 3 million years ago).

Compared to earlier species, Metaxytherium serresii shows a progressive reduction in size, probably as an adaptive response to the environmental changes that preceded the Messinian salinity crisis. Between 5.96 and 5.33 million years ago, indeed, the closure of the Strait of Gibraltar isolated the Mediterranean Sea, causing drastic evaporation and profound transformations of marine and coastal environments.