New postcranial elements of mesonychid mammals from the Ypresian of France: New hypotheses for the radiation and evolution of the mesonychids in Europe

• Published in: Journal of mammalian evolution 2023-06, Vol.30 (2), p.371-401
• Main Authors: Solé, Floréal, Fournier, Morgane, Ladevèze, Sandrine, Le Verger, Kévin, Godinot, Marc, Laurent, Yves, Smith, Thierry
• Format: Article
• Language: English
• Subjects: Animal Genetics and Genomics; Anthropology; Biomedical and Life Sciences; Eocene; Evolution; Evolutionary Biology; Human Genetics; Hyaenodictis raslanloubatieri; Hyaenodictis rougierae; Hypotheses; Life Sciences; Locomotion; Morphology; Original Paper; Pachyaena gigantea; Phylogenetics; Phylogeny; Radiation; Sciences of the Universe; Vertebrae
• ISSN: 1064-7554; 1573-7055
• DOI: 10.1007/s10914-023-09651-x

New postcranial elements of two mesonychids that lived during the Ypresian (early Eocene) in Europe are here described. The postcranial bones found at La Borie (France; ≈MP8 + 9) can be confidently ascribed to Hyaenodictis raslanloubatieri , while the astragalus found at Palette (France; ≈MP7) probably represents H. rougierae. Our study demonstrates that H. raslanloubatieri and H. rougierae were digitigrade in posture and relatively cursorial in locomotion. A single lumbar vertebra was recovered at La Borie and referred to H. raslanloubatieri ; this element suggests this species was a moderately dorsostable predator. In addition, we illustrate the first maxillary fragment referable to H. raslanloubatieri , also discovered at La Borie. In comparison, we describe the postcranial elements of Pachyaena gigantea partially published in the early twentieth century, probably a plantigrade predator species. Morphological data derived from the La Borie specimens were included in phylogenetic analyses and support the reinstatement and monophyly of Hyaenodictis . Hyaenodictis was considered to be a junior synonym of Dissacus , but here we find that the Hyaenodictis clade includes almost all European mesonychids formerly referred to Dissacus along with the North American Wasatchian species H. willwoodensis .