A new genus of amebelodonts from the Miocene of China and a re-examination of the phylogeny of the Amebelodontidae

Abstract

Amebelodontidae, a group of proboscideans with distinctive shovel-like mandibular symphysis and tusks, have been the subject of contentious classification due to ambiguous morphological traits. We construct a comprehensive character matrix for longirostrine elephantiform species and conduct a cladistic analysis using the most-parsimonious approach. Our results strongly support the monophyly of Amebelodontidae but necessitate taxonomic revisions. Notably, we propose a new genus, Saegusaia, for Chinese specimens previously classified as Protanancus, which represent a more basal lineage than true Protanancus found in Africa and South Asia. We identify two monophyletic subfamilies within Amebelodontidae: Platybelodontinae and Amebelodontinae. Megabelodon and Eubelodon, traditionally considered aberrant gomphotheres lacking mandibular tusks, are now placed within the Amebelodontinae based on their cheek teeth similarity to other amebelodontines. Additionally, our re-evaluation suggests that Konobelodon britti may be a junior synonym of Torynobelodon campester, restricted to North America. Eurasian forms attributed to ‘Konobelodon’ are stem elephantoids rather than members of Amebelodontidae. These revised classifications enhance our understanding of ­Amebelodontidae and other longirostrine elephantiforms, highlighting their importance in the broader context of proboscidean evolution. They represent a critical stage in the diversification and adaptation of early elephants and their relatives.