Moeritherium

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Moeritherium
Temporal range: Late Eocene, 37–35  Ma
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Moeritherium trigodon skull cast (cropped).jpg
M. trigodon skull cast, at the AMNH.
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Proboscidea
Family: Moeritheriidae
C.W. Andrews, 1906
Genus: Moeritherium
C.W. Andrews, 1901
Type species
Moeritherium lyonsi
Andrews, 1901
Species

Moeritherium ("the beast from Lake Moeris") is an extinct genus of basal proboscideans from the Eocene of North and West Africa.. It was related to elephants and, more distantly, to sea cows and hyraxes.

Contents

Description

Moeritherium was a rotund semi-aquatic mammal with short, stubby legs that lived about 37–35 million years ago. [1] Its body shape and lifestyle demonstrate convergent evolution with pigs, tapirs, and the pygmy hippopotamus. Moeritherium was smaller than most or all later proboscideans, standing only 70 centimetres (2.3 ft) high at the shoulder and weighing 235 kilograms (518 lb). [2]

The shape of the skull suggests that, while Moeritherium did not have an elephant-like trunk, it may have had a broad flexible upper lip like a tapir's for grasping aquatic vegetation. The second incisor teeth formed small tusks, although these would have looked more like the teeth of a hippo than a modern elephant. [3] [4]

Ecology

Isotopic analysis suggests that Moertherium was amphibious/semiaquatic and probably consumed freshwater plants. [5]

Discovery

In 1901, Charles William Andrews described Moeritherium lyonsi from fossil remains found in the Qasr el Sagha Formation in the Al Fayyum in Egypt. Andrews described Moeritherium gracile from fossil remains of a smaller specimen found in the same area in 1902 in a fluvio-marine formation, [6] [7] that is a river estuary wetlands to brackish lagoon paleoenvironment. In 1904, the first Moeritherium trigodon fossils were discovered by Charles Andrews in the deposits of an oasis in Al Fayyum. [1] [8] It is also found in other sites around North and West Africa. [9]

In 1911, Max Schlosser of Munich divided Moeritherium lyonsi into two species: Moeritherium lyonsi, a large form from the Qasr-el-Sagha formation, and a new large species M. andrewsi from a fluvio-marine formation. [6] [7] [10] In 2006, Moeritherium chehbeurameuri has been described from fossil remains found in the early late Eocene locality of Bir El Ater, Algeria. [11]

Moeritherium andrewsi.jpg
Partial M. andrewsi skull with reconstruction at the AMNH
Moeritherium skull and jaws (cropped).jpg
Partial M. andrewsi skull with reconstruction at the AMNH
Moeritherium sp.jpg
M. sp. skeleton in Japan
Moeritherium lyonsi skull front.jpg
M. lyonsi skull front view, at the Royal BC Museum
Moeritherium.jpg
1920 illustration.
Moeritherium NT small.jpg
2016 reconstruction

Classification

Moeritherium is not thought to be directly ancestral to modern elephants; it was a branch of Proboscidea that died out, leaving no descendants. There were several species of other basal proboscideans in existence during the Eocene, and some, such as Phiomia and Palaeomastodon , looked comparatively more like modern elephants. However, Moeritherium was clearly a side branch of the proboscidean family tree, having evolved to resemble other rotund semiaquatic mammals such as pigs, tapirs, and hippos instead of having the typical proboscidean body form. [12]

Related Research Articles

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

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, strictly defined, 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">Deinotheriidae</span> Prehistoric family of mammals

Deinotheriidae is a family of prehistoric elephant-like proboscideans that lived during the Cenozoic era, first appearing in Africa, then spreading across southern Asia (Indo-Pakistan) and Europe. During that time, they changed very little, apart from growing much larger in size; by the late Miocene, they had become the largest land animals of their time. Their most distinctive features were their lack of upper tusks and downward-curving tusks on the lower jaw.

<i>Prodeinotherium</i> Extinct genus of proboscideans

Prodeinotherium is an extinct representative of the family Deinotheriidae that lived in Africa, Europe, and Asia in the early and middle Miocene. Prodeinotherium, meaning "before terrible beast", was first named in 1930, but soon after, the only species in it, P. hungaricum, was reassigned to Deinotherium. During the 1970s, however, the two genera were once again separated, with Prodeinotherium diagnosed to include Deinotherium bavaricum, Deinotherium hobleyi, and Deinotherium pentapotamiae, which were separated based on geographic location. The three species are from Europe, Africa, and Asia, respectively. However, because of usage of few characters to separate them, only one species, P. bavaricum, or many more species, including P. cuvieri, P. orlovii, and P. sinense may be possible.

<span class="mw-page-title-main">Wadi al Hitan</span> Paleontological site in the Faiyum Governorate of Egypt

Wādī al-Ḥītān is a paleontological site in the Faiyum Governorate of Egypt, some 150 kilometres (93 mi) south-west of Cairo. It was designated a UNESCO World Heritage Site in July 2005 for its hundreds of fossils of some of the earliest forms of whale, the archaeoceti. The site reveals evidence for the explanation of one of the greatest mysteries of the evolution of whales: the emergence of the whale as an ocean-going mammal from a previous life as a land-based animal.

<i>Pakicetus</i> Genus of ancient whales

Pakicetus is an extinct genus of amphibious cetacean of the family Pakicetidae, which was endemic to Pakistan during the Ypresian period, roughly 50 million years ago. It was a wolf-like mammal, about 1 metre to 2 metres long, and lived in and around water where it ate fish and other animals. The vast majority of paleontologists regard it as the most basal whale, representing a transitional stage between land mammals and whales. It belongs to the even-toed ungulates with the closest living non-cetacean relative being the hippopotamus.

<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.

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

Anthracobunidae is an extinct family of stem perissodactyls that lived in the early to middle Eocene period. They were originally considered to be a paraphyletic family of primitive proboscideans possibly ancestral to the Moeritheriidae and the desmostylians. The family has also thought to be ancestral to the Sirenia.

Numidotheriidae is an extinct family of primitive proboscideans that lived from the late Paleocene to the early Oligocene periods of North Africa.

<i>Numidotherium</i> Genus of mammals

Numidotherium is an extinct genus of early proboscideans, discovered in 1984, that lived during the middle Eocene of North Africa some 46 million years ago. It was about 90-100 cm tall at the shoulder and weighed about 250-300 kg.

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

Phosphatherium escuillei is a basal proboscidean that lived from the Late Paleocene to the early stages of the Ypresian age. Research has suggested that Phosphatherium existed during the Eocene period.

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

Barytherium is a genus of an extinct family (Barytheriidae) of primitive proboscideans that lived during the late Eocene and early Oligocene in North Africa. The type species is Barytherium grave, found at the beginning of the 20th century in Fayum, Egypt. Since then, more complete specimens have been found at Dor el Talha, Libya. More fossils were also discovered in 2011 in the Aidum area in Dhofar by Oman's Ministry of Heritage and Culture, which was named Barytherium omansi.

Eogavialis is an extinct genus of eusuchian crocodylomorph, usually regarded as a gavialoid crocodylian. It superficially resembles Tomistoma schlegelii, the extant false gharial, and consequently material from the genus was originally referred to Tomistoma. Indeed, it was not until 1982 that the name Eogavialis was constructed after it was realised that the specimens were from a more basal form.

<span class="mw-page-title-main">Jebel Qatrani Formation</span> Geologic formation in Egypt

The Jebel Qatrani Formation is a geologic formation located in the Faiyum Governorate of central Egypt. It is exposed between the Jebel Qatrani escarpment and the Qasr el Sagha escarpment, north of Birket Qarun lake near Faiyum. The formation conformably overlies the Qasr el Sagha Formation and is topped by the Widan el Faras Basalt. The age of the formation has been subject to debate, but the most recent research indicates that it covers both the latest parts of the Eocene and the Early Oligocene, spanning over the boundary between these two time periods.

The Qasr el Sagha Formation is a geological formation located in Egypt. The formation is part of the Wadi El Hitan World Heritage Site. The Qasr el Sagha Formation overlies the Birket Qarun Formation and is overlain by the Gebel Qatrani Formation. The sandstones and shales of the formation were deposited in a deltaic to shallow marine environment. It dates to the Late Eocene.

Egypt has many fossil-bearing geologic formations, in which many dinosaurs have been discovered.

<i>Saghacetus</i> Genus of mammals

Saghacetus is an extinct genus of basilosaurid early whale, fossils of which have been found in the Upper Eocene Qasr el Sagha Formation, Egypt.

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

Apterodon is an extinct genus of hyaenodontid mammals that lived from the late Eocene through the middle Oligocene epoch in Africa and Europe. It is closely related to the African Quasiapterodon, and together it, they comprise the hyainailurids subfamily Apterodontinae.

Saloumia is an extinct genus of the order Proboscidea. It is one of the oldest members of the order and lived in the middle Eocene of Senegal. It is known only from a single molar, whose pronounced bumpy chewing surface indicates it is probably closely related to Moeritherium.

Dagbatitherium is an extinct genus of proboscideans. So far a single molar from the phosphate basins of Togo in West Africa has been found. The fossil dates to the Middle Eocene, around 47 million years ago. A striking feature of the tooth are the three pairs of cusps oriented transversely to the longitudinal axis of the tooth. This feature is found in more derived proboscideans, which are grouped in the Elephantiformes. For its age, Dagbatitherium is the earliest member of Elephantiformes to date. Furthermore, it is characterized by a low tooth crown and a humped occlusal pattern. The genus was described in 2021.

References

  1. 1 2 Koehl, D. 2006 The genus Moeritherium, ancestor of elephants. Downloaded on 6 December 2006.
  2. Larramendi, A. (2016). "Shoulder height, body mass and shape of proboscideans" (PDF). Acta Palaeontologica Polonica. 61. doi: 10.4202/app.00136.2014 .
  3. Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 238. ISBN   978-1-84028-152-1.
  4. Savage, RJG; Long, MR (1986). Mammal Evolution: an illustrated guide. New York: Facts on File. p.  147. ISBN   978-0-8160-1194-0.
  5. Liu, Alexander G. S. C.; Seiffert, Erik R.; Simons, Elwyn L. (2008-04-15). "Stable isotope evidence for an amphibious phase in early proboscidean evolution". Proceedings of the National Academy of Sciences. 105 (15): 5786–5791. Bibcode:2008PNAS..105.5786L. doi: 10.1073/pnas.0800884105 . ISSN   0027-8424. PMC   2311368 . PMID   18413605.
  6. 1 2 Matsumoto, H. 1922. Revision of Palæomastodon and Mœritherium. Palæomastodon intermedius, and Phiomia osborni, new species. American Museum Novitates. Number 51, November 21.
  7. 1 2 Matsumoto, H. 1923. A Contribution to the Knowledge of Mœritherium. Bulletin of the American Museum of Natural History; v. 48, article 4. p. 97-140.
  8. ABC Online. 2002. ABC - Science - Beasts - Moeritherium Factfile Downloaded on 6 December 2006.
  9. BBC Homepage. 2006. - Science & Nature - Wildfacts - Moeritherium Downloaded on 6 December 2006.
  10. Schlosser Max (1911) "Beiträge zur Kenntnis der oligozänen Landsäugetiere aus dem Fayum, Ägypten." Beiträge zur Paläontologie und Geologie Österreich-Ungarns, 24: 1–167.
  11. Delmer, Cyrille; Mahboubi, Mohamed; Tabuce, Rodolphe; Tassy, Pascal (2006). "A New Species of Moeritherium (Proboscidea, Mammalia) from the Eocene of Algeria: New Perspectives on the Ancestral Morphotype of the Genus". Palaeontology. 49 (2): 421–434. Bibcode:2006Palgy..49..421D. doi: 10.1111/j.1475-4983.2006.00548.x .
  12. Stockdale, M.; Musgrove, L. Ancient Proboscideans Archived 2017-03-16 at the Wayback Machine University of Bristol 2011.