Eozygodon

Eozygodon Temporal range: Early Miocene ~23–16 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Occlusal view of the third lower molar (m3) of E. morotoensis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Proboscidea
Family:	†Mammutidae
Genus:	†Eozygodon Tassy & Pickford, 1983
Species:	†E. morotoensis
Binomial name
†Eozygodon morotoensis Tassy & Pickford, 1983

Eozygodon is an extinct genus of proboscidean in the family Mammutidae. It is a monotypic genus that contains the single species E. morotoensis, named in 1983.^[1] It is known from the Early Miocene of Africa (Kenya, Uganda, Namibia)^[2] and well as possibly the Middle Miocene of China.^[3] It is considered a primitive member of the family, retaining a long lower jaw (longirostrine) with lower tusks.^[3][4] The upper tusks are small, and are only slightly divergent from each other. The skull of the young adult (around 24-26 years old in African elephant tooth wear equivalent years) AM 02 from Auchas, Namibia, was around the size of that of a 10 year old American mastodon,^[5] around 60 centimetres (2.0 ft) in maximum length.^[6] Some authors suggest that Eozygodon could be less closely related to other members of Mammutidae than other mammutids are to Elephantida, making Mammutidae as typically defined paraphyletic.^[5]

Palaeoecology

Dental mesowear from East African specimens suggests a browsing diet.^[7] δ¹³C_enamel values in E. morotoensis from Moroto were very high.^[8]

References

1. Tassy, P. and Pickford, M. (1983). Un nouveau mastodonte zygolophodonte (Proboscidea, Mammalia) dans le Miocène Inférieur d'Afrique orientale: Systématique et paléoenvironnement. Géobios 16: 53-77.
2. William J. Sanders; Emmanuel Gheerbrant; John M. Harris; Haruo Saegusa; Cyrille Delmer (2010). "Proboscidea". In Werdelin, Lars; Sanders, William Joseph (eds.). Cenozoic Mammals of Africa. University of California Press. pp. 186–. ISBN 978-0-520-25721-4.
3. Zhang, Xiaoxiao; Wang, Shiqi (2021-09-02). "First report of Eozygodon (Mammutidae, Proboscidea) in Eurasia". Historical Biology. 33 (9): 1661–1670. Bibcode:2021HBio...33.1661Z. doi:10.1080/08912963.2020.1723579. ISSN 0891-2963. S2CID 213467027.
4. Mothé, Dimila; Avilla, Leonardo S.; Zhao, Desi; Xie, Guangpu; Sun, Boyang; Mothé, Dimila; Avilla, Leonardo S.; Zhao, Desi; Xie, Guangpu (2016). "A new Mammutidae (Proboscidea, Mammalia) from the Late Miocene of Gansu Province, China". Anais da Academia Brasileira de Ciências. 88 (1): 65–74. doi:10.1590/0001-3765201520150261. ISSN 0001-3765. PMID 26839998.
5. Tassy, P. 2018. Remarks on the cranium of Eozygodon morotoensis (Proboscidea, Mammalia) from the early Miocene of Africa, and the question of the monophyly of Elephantimorpha. Revue Paléobiologie, Genève, 37:593-607.
6. M. Pickford "New Proboscidea from the Miocene strata of the lower Orange River Valley, Namibia" Memoir Geological Survey Namibia, 19 (2003), pp. 207-256
7. Saarinen, Juha; Lister, Adrian M. (2023-08-14). "Fluctuating climate and dietary innovation drove ratcheted evolution of proboscidean dental traits". Nature Ecology & Evolution. 7 (9): 1490–1502. Bibcode:2023NatEE...7.1490S. doi:10.1038/s41559-023-02151-4. ISSN 2397-334X. PMC 10482678. PMID 37580434.
8. Arney, Irisa; Locke, Ellis M.; Miller, Ellen R.; Nengo, Isaiah O. (10 January 2024). "Stable isotope (ẟ13C, ẟ18O) paleoecology of the late Early Miocene mammalian fauna from Buluk, Kenya". Palaeontologia Electronica. doi:10.26879/1335. Retrieved 14 November 2024 – via Palaeontologia Electronica.