Eozygodon

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Eozygodon
Temporal range: Early Miocene
~23–16  Ma
Eozygodon molars.png
Occlusal view of the third lower molar (m3) of E. morotoensis
Scientific classification OOjs UI icon edit-ltr.svg
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] δ13Cenamel values in E. morotoensis from Moroto were very high. [8]

Related Research Articles

<span class="mw-page-title-main">Proboscidea</span> Order of mammals including elephants

Proboscidea is a taxonomic order of afrotherian mammals containing one living family (Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives. Three species of elephant are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant.

<span class="mw-page-title-main">Mastodon</span> Extinct genus of proboscideans

A mastodon is a member of the genus Mammut, which was endemic to North America and lived from the late Miocene to the early Holocene. Mastodons belong to the order Proboscidea, the same order as elephants and mammoths. Mammut is the type genus of the extinct family Mammutidae, which diverged from the ancestors of modern elephants at least 27–25 million years ago, during the Oligocene.

<span class="mw-page-title-main">Mammutidae</span> Extinct family of mammals

Mammutidae is an extinct family of proboscideans belonging to Elephantimorpha. It is best known for the mastodons, which inhabited North America from the Late Miocene until their extinction at beginning of the Holocene, around 11,000 years ago. The earliest fossils of the group are known from the Late Oligocene of Africa, around 24 million years ago, and fossils of the group have also been found across Eurasia. The name "mastodon" derives from Greek, μαστός "nipple" and ὀδούς "tooth", referring to their characteristic teeth.

<span class="mw-page-title-main">Gomphothere</span> Extinct family of proboscidean mammals

Gomphotheres are an extinct group of proboscideans related to modern elephants. First appearing in Africa during the Oligocene, they dispersed into Eurasia and North America during the Miocene and arrived in South America during the Pleistocene as part of the Great American Interchange. Gomphotheres are a paraphyletic group ancestral to Elephantidae, which contains modern elephants, as well as Stegodontidae.

<i>Gomphotherium</i> Extinct genus of elephant-like mammals

Gomphotherium is an extinct genus of gomphothere proboscidean from the Neogene of Eurasia, Africa and North America. It is the most diverse genus of gompothere, with over a dozen valid species. The genus is probably paraphyletic.

<i>Anancus</i> Genus of proboscideans

Anancus is an extinct genus of "tetralophodont gomphothere" native to Afro-Eurasia, that lived from the Tortonian stage of the late Miocene until its extinction during the Early Pleistocene, roughly from 8.5–2 million years ago.

<i>Stegomastodon</i> Extinct genus of mammals

Stegomastodon is an extinct genus of gomphotheres. It ranged throughout North America from the Pliocene, to the Early Pleistocene. The former South American species have been synonymized with Notiomastodon platensis.

<i>Sinomastodon</i> Extinct genus of gomphothere proboscidean

Sinomastodon is an extinct gomphothere genus known from the Late Miocene to Early Pleistocene of Asia, including China, Japan, Thailand, Myanmar, Indonesia and probably Kashmir.

<i>Tetralophodon</i> Extinct genus of mammals

Tetralophodon is an extinct genus of "tetralophodont gomphothere" belonging to the superfamily Elephantoidea, known from the Miocene of Afro-Eurasia.

<i>Rhynchotherium</i> Extinct genus of proboscid

Rhynchotherium is an extinct genus of proboscidea endemic to North America and Central America during the Miocene through Pliocene from 13.650 to 3.6 Ma, living for approximately 10 million years.

Gnathabelodon is an extinct genus of gomphothere endemic to North America that includes species that lived during the Middle to Late Miocene.

<i>Eubelodon</i> Extinct genus of proboscid

Eubelodon is an extinct genus of gomphothere which lived in North America during the Miocene Epoch. It contains a single species: Eubelodon morrilli.

<i>Zygolophodon</i> Extinct genus of mammutid proboscidean

Zygolophodon is an extinct genus of mammutid proboscidean that lived during the Miocene in Africa, Eurasia, and North America.

<i>Notiomastodon</i> Extinct genus of gomphothere elephantimorph native to South America

Notiomastodon is an extinct genus of gomphothere proboscidean, endemic to South America from the Pleistocene to the beginning of the Holocene. Notiomastodon specimens reached a size similar to that of the modern Asian elephant, with a body mass of 3-4 tonnes. Like other brevirostrine gomphotheres such as Cuvieronius and Stegomastodon, Notiomastodon had a shortened lower jaw and lacked lower tusks, unlike more primitive gomphotheres like Gomphotherium.

<i>Choerolophodon</i> Extinct genus of mammals

Choerolophodon is an extinct genus of proboscidean that lived during the Miocene of Eurasia and Africa. Fossils of Choerolophodon have been found in Africa, Southeast Europe, Turkey, Iraq, Iran, the Indian subcontinent, and China.

<span class="mw-page-title-main">Elephantimorpha</span> Clade of mammals

Elephantimorpha is a clade of proboscideans that contains the Mammutidae (mastodons), as well as Elephantida. All members of this group have the horizontal tooth replacement typical of modern elephants, unlike more primitive members of the Elephantiformes. Like modern elephants, the ancestor of Elephantimorpha was likely capable of communicating via infrasonic calls. While early elephantimorphs generally had lower jaws with an elongated mandibular symphysis at the front of the jaw with well developed lower tusks/incisors, from the Late Miocene onwards, many groups convergently developed brevirostrine (shortened) lower jaws with vestigial or no lower tusks, probably corresponding with the elongation and increasingly dexterity of the trunk allowing it to be used as the primary feeding organ.

<span class="mw-page-title-main">Elephantiformes</span> Suborder of mammals

Elephantiformes is a suborder within the order Proboscidea. Members of this group are primitively characterised by the possession of upper tusks, an elongated mandibular symphysis and lower tusks, and the retraction of the facial region of the skull indicative of the development of a trunk. The earliest known member of the group, Dagbatitherium is known from the Eocene (Lutetian) of Togo, which is only known from isolated teeth, while other primitive elephantiforms like Phiomia and Palaeomastodon are known from the Early Oligocene onwards. Phiomia and Palaeomastodon are often collectively referred to as "palaeomastodonts" and assigned to the family Palaeomastodontidae. Most diversity of the group is placed in the subclade Elephantimorpha, which includes mastodons, as well as modern elephants and gomphotheres (Elephantida). It is disputed as to whether Phiomia is closely related to both Mammutidae and Elephantida with Palaeomastodon being more basal, or if Palaeomastodon is closely related to Mammutidae and Phiomia more closely related to Elephantida.

<i>Sinomammut</i> Extinct genus of mammals

Sinomammut is a mammutid proboscidean from the Miocene of China. Only one species, S. tobieni, is known, named in 2016.

<span class="mw-page-title-main">Amebelodontidae</span> Extinct family of mammals

Amebelodontidae is an extinct family of large herbivorous proboscidean mammals related to elephants. They were formerly assigned to Gomphotheriidae, but recent authors consider them a distinct family. They are distinguished from other proboscideans by having flattened lower tusks and very elongate mandibular symphysis. The lower tusks could grow to considerable size, with those of Konobelodon reaching 1.61 metres (5.3 ft) in length. Their molar teeth are typically trilophodont, and possessed posttrite conules. In the past, amebelodonts' shovel-like mandibular tusks led to them being portrayed scooping up water plants, however, dental microwear suggests that they were browsers and mixed feeders. The lower tusks have been proposed to have had a variety of functions depending on the species, including stripping bark, cutting through vegetation, as well as possibly digging. They first appeared in Africa during the Early Miocene, and subsequently dispersed into Eurasia and then North America. They became extinct by the beginning of the Pliocene. While some phylogenetic studies have recovered Amebelodontidae as a monophyletic group that forms the sister group to Gomphotheriidae proper, some authors have argued that Amebelodontidae may be polyphyletic, with it being suggested that the shovel-tusked condition arose several times independently within Gomphotheriidae, thus rendering the family invalid.

Eurybelodon is an extinct genus of proboscidean in the family Amebelodontidae. It lived in the Clarendonian age of the Miocene.

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. 1 2 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. 1 2 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.