Hyaenodictis

Hyaenodictis Temporal range: Early Eocene (Ypresian), 55.5–48  Ma PreꞒ Ꞓ O S D C P T J K Pg N Da. S T Ypr. Lut. B Pr. Rup. Ch.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Placentalia
Order:	† Mesonychia
Family:	† Mesonychidae
Genus:	† Hyaenodictis Lemoine, 1880
Type species
†Hyaenodictis filholi
Other species
†H. blayaci Solé et al., 2023 †H. progressus Solé et al., 2023 †H. raslanloubatieri Solé et al., 2023 †H. rougierae Solé et al., 2023 †H. willwoodensis Solé et al., 2023

Hyaenodictis is a monophyletic extinct genus of mesonychid that inhabited Europe and North America during the Early Eocene. ^{[1] [2]} Initially, this genus was thought to have been synonymous with Dissacus , ^[2] however recent analysis had found differentiations which resulted in the two to being considered distinct from one another. ^[1] Hyaenodictis would be contemporary with Pachyaena , roaming Southwestern Europe, while the latter roamed Northwestern Europe. Following the extinction of Pachyaena, Hyaenodictis would later disperse into Northwestern Europe. ^[2]

It was the last European mesonychid, going extinct roughly 48 Ma during the Ypresian-Lutetian Mammal Turnover event. Their extinction saw the diversification in hyaenodonts species and an increase in body sizes. ^{[3] [4]}

Taxonomy

Following the discovery of D. raslanloubatieri and D. rougierae, Solé et al. (2018) recovered Dissacus as a paraphyletic genus. Most European species of Dissacus within the European Dissacus clade, with D. willwoodensis being recovered as a sister taxon to the clade. D. europaeus, the oldest European species, was recovered to not be closely related to the clade as it didn't have typical features within the clade such as the reduction of m3. ^[2] Solé et al. (2023) classified Hyaenodictis as a distinct genus with the type species being H. filholi, which was found in the Epernay area of Northwestern Europe. Other European species included H. blayaci, H. progressus, H. rougierae, and H. raslanloubatieri, in addition to one North American species, H. willwoodensis. ^[1] Their analysis recovered Hyaenodictis as a monophyletic group within the mesonychid family. ^[1]

Extinction

European Hyaenodictis went extinct roughly 48 Ma, at the end of the Ypresian, which coincided with the Ypresian-Lutetian Mammal Turnover event. Their extinction likely coincided with the cooling period following the end of the Early Eocene Climatic Optimum. The turnover event is contemporary with the Bridgerian Crash in North America, which saw major mammalian diversification losses. ^[3] Following the extinction of mesonychids and oxyaenids, hyaenodonts saw an increase in diversification and body sizes, ^{[3] [5] [6]} with some such as Cartierodon grew large, weighing 29 kg (64 lb). ^[4]

References

1. Solé, Floréal; Fournier, Morgane; Ladevèze, Sandrine; Le Verger, Kévin; Godinot, Marc; Laurent, Yves; Smith, Thierry (18 April 2023). "New postcranial elements of mesonychid mammals from the Ypresian of France: New hypotheses for the radiation and evolution of the mesonychids in Europe" . Journal of Mammalian Evolution . 30 (2): 371–401. doi:10.1007/s10914-023-09651-x. ISSN   1064-7554 . Retrieved 21 November 2024– via Springer Link.
2. Solé, Floréal; Godinot, Marc; Laurent, Yves; Galoyer, Alain; Smith, Thierry (2018). "The European Mesonychid Mammals: Phylogeny, Ecology, Biogeography, and Biochronology" . Journal of Mammalian Evolution. 25: 339–379. doi:10.1007/s10914-016-9371-8.
3. Solé, Floréal; Fischer, Valentin; Le Verger, Kévin; Mennecart, Bastien; Speijer, Robert P.; Peigné, Stéphane; Smith, Thierry (2022). "Evolution of European carnivorous mammal assemblages through the Paleogene". Biological Journal of the Linnean Society. 135 (4): 734–753. doi:10.1093/biolinnean/blac002.
4. Solé, Floréal; Mennecart, Bastien (2019). "A large hyaenodont from the Lutetian of Switzerland expands the body mass range of the European mammalian predators during the Eocene". Acta Palaeontologica Polonica . 64 (2). doi: 10.4202/app.00581.2018 . Retrieved 10 September 2024.
5. Solé, Floréal; Falconnet, Jocelyn; Yves, Laurent (24 July 2014). "New proviverrines (Hyaenodontida) from the early Eocene of Europe; phylogeny and ecological evolution of the Proviverrinae: Evolution of the Proviverrinae". Zoological Journal of the Linnean Society . 171 (4): 878–917. doi:10.1111/zoj.12155 . Retrieved 7 November 2024– via Wiley Online Library.
6. Solé, Floreal; Morlo, M.; Schaal, T.; Lehmann, T. (2021). "New hyaenodonts (Mammalia) from the late Ypresian locality of Prémontré (France) support a radiation of the hyaenodonts in Europe already at the end of the early Eocene". Geobios . 66–67: 119–141. Bibcode:2021Geobi..66..119S. doi:10.1016/j.geobios.2021.02.004. ISSN   0016-6995. S2CID   234848856.