The Late Miocene hippopotamid, Archaeopotamus pantanellii nov. comb., from the Casino Basin (Tuscany, Italy): paleobiogeographic implications

ABSTRACT

Fossil remains from the latest Messinian of Casino Basin (Tuscany, Italy) are known since the beginning of the nineteenth century. Among the others, the mammal assemblage includes Mesopithecus pentelicus, Tapirus arvernensis, Propotamochoerus provincialis and scarce and poorly preserved remains of a hippopotamid, consisting of a mandibular symphysis fragment, an apical fragment of a lower canine, some isolated lower incisors, a fragmented second upper premolar and a second lower molar. These specimens were initially referred as Hippopotamus hipponensis and later ascribed to the new species Hippopotamus pantanellii (recently reported as Hexaprotodon? pantanellii). However, this attribution has been disputed during the past years. The hippopotamid remains from the Casino Basin are revised here in order to clarify their systematic position and to infer paleobiogeographic and evolutionary patterns within the Mediterranean fossil record of Hippopotamidae. The morphology of the remains collected from the Casino Basin more closely resembles the African than the Asian hippopotamids’ lineage and therefore the Tuscan remains should be more properly referred as Archaeopotamus pantanellii. The latter species probably dispersed into Tuscany from the Iberian Peninsula where the presence of Archaeopotamus crusafonti is well documented.

KEYWORDS:

• Mammal Neogene zone 13
• Central Italy
• Hippopotamidae
• systematics

Acknowledgments

This research benefited from the grant UIDB/04035/2020 by the Fundação para a Ciência e Tecnologia to GeoBioTec. R.M. wants to thank Prof. Martin Pickford for the help and for the fruitful conversations. The authors also thank C. Dal Sasso and G.G. Bardelli (MSNM), E. Cioppi (IGF), R. Barbieri (MGGC), C. Mangoni (MCZR), C. Sarti (MSNAF), F. Farsi, G. Manganelli (MZUF) and C. Sorbini (MSNCC) for their assistance and support during the visits to fossil collections. This research received support from the SYNTHESYS+ project http://www.synthesys.info/, which is financed by the European Community Research Infrastructure Action under the H2020 Integrating Activities Programme, Project number 823827 at the Museo Nacional de Ciencias Naturales (CSIC). L.P. thanks the European Commission’s Research Infrastructure Action, EU-SYNTHESYS+ project BE-TAF-1367; part of this research received support from the SYNTHESYS+ Project http://www.synthesys.info/which is funded by the European Commission.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/08912963.2023.2194912

Additional information

Funding

This work was supported by the Fundação para a Ciência e Tecnologia [2021.08458.BD].