Acta Palaeontologica Polonica

Morphological and systematic re-assessment of the late Oligocene “Halitherium” bellunense reveals a new crown group genus of Sirenia

Manja Voss, Silvia Sorbi, and Daryl P. Domning

Acta Palaeontologica Polonica 62 (1), 2017: 163-172 doi:

Halitheriumbellunense is exclusively known from a single individual from upper Oligocene glauconitic sandstone near Belluno, northern Italy. According to a review of its morphological basis, which consists of associated cranial elements, some vertebrae and ribs, this specimen is identified as a juvenile, because the first upper incisor (I1) and supposedly second upper molar (M2) are not fully erupted. However, its juvenile status allowed only cautious conclusions on its taxonomy and systematic affinity. The presence of a nasal process of the premaxilla with a broadened and bulbous posterior end, and a lens-shaped I1, corroborate an evolutionarily-derived status of this species that places it well  within the sirenian crown group Dugonginae. Considering these new data and in order to avoid continued misuse of the inappropriate generic name of Halitherium, a new generic name, Italosiren gen. nov., and emended species diagnosis are supplied for this taxon.

Key words: Mammalia, Tethytheria, Sirenia, Dugonginae, evolution, Oligocene, Italy.

Manja Voss [], Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany. Silvia Sorbi [], Museo di Storia Naturale, Università di Pisa, Via Roma 79, 56011 Calci, Pisa, Italy. Daryl P. Domning [], Laboratory of Evolutionary Biology, Department of Anatomy, Howard University, Washington, District of Columbia 20059,USA.

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