Embrithopoda | |
---|---|
Arsinoitherium zitteli [2] | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Clade: | Paenungulatomorpha |
Grandorder: | Paenungulata |
Mirorder: | Tethytheria |
Order: | † Embrithopoda Andrews 1906 |
Families | |
Embrithopoda ("heavy-footed") is an order of extinct mammals known from Asia, Africa and Eastern Europe. Most of the embrithopod genera are known exclusively from jaws and teeth dated from the late Paleocene to the late Eocene; however, the order is best known from its terminal member, the elephantine Arsinoitherium . [3]
While embrithopods bore a superficial resemblance to rhinoceroses, their horns had bony cores covered in keratinized skin. Not all embrithopods possessed horns, either. Despite their appearance, they have been regarded as related to elephants, not perissodactyls. [4]
As tethytheres, [5] the Embrithopoda have been believed to be part of the clade Afrotheria. However, a study of the basal arsinoitheriid, Palaeoamasia, suggests that embrithopods are not tethytheres or even paenungulates, and that they need to be better sampled in an analysis of eutherian relationships to clarify if they are even afrotherians. [6] It is also not clear if embrithopods originated in Africa or Eurasia. [6] However, recent findings demonstrate an African origin for embrithopods and furthermore a relationship with other paenungulates, albeit having diverged earlier than previously thought. [7]
Fossils of embrithopods, such as Arsinoitherium , have been found in Egypt, Ethiopia, Kenya, Morocco, Mongolia, Turkey, Romania, Namibia, [8] Tunisia [9] and Croatia. [10] Until the 1970s, only Arsinoitherium itself was known, appearing isolated in the fossil record. [4]
McKenna & Manning 1977 and McKenna & Bell 1997 considered Phenacolophus from Mongolia a primitive embrithopod, although this attribution was challenged by several other authors. [11] A 2016 cladistic study found Phenacolophus as a stem-perissodactyl and the embrithopods at the base of Altungulata. [12] [6] More recently, an afrothere identity has been vindicated, albeit more basal than previously assumed. [7]
Order Embrithopoda Andrews 1906 sensu Prothero & Schoch 1989 (=Barypoda Andrews 1904) [13]
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.
Afrotheria is a superorder of placental mammals, the living members of which belong to groups that are either currently living in Africa or of African origin: golden moles, elephant shrews, otter shrews, tenrecs, aardvarks, hyraxes, elephants, sea cows, and several extinct clades. Most groups of afrotheres share little or no superficial resemblance, and their similarities have only become known in recent times because of genetics and molecular studies. Many afrothere groups are found mostly or exclusively in Africa, reflecting the fact that Africa was an island continent from the Cretaceous until the early Miocene around 20 million years ago, when Afro-Arabia collided with Eurasia.
Paenungulata is a clade of "sub-ungulates", which groups three extant mammal orders: Proboscidea, Sirenia, and Hyracoidea (hyraxes). At least two more possible orders are known only as fossils, namely Embrithopoda and Desmostylia.
Condylarthra is an informal group – previously considered an order – of extinct placental mammals, known primarily from the Paleocene and Eocene epochs. They are considered early, primitive ungulates. It is now largely considered to be a wastebasket taxon, having served as a dumping ground for classifying ungulates which had not been clearly established as part of either Perissodactyla or Artiodactyla, being composed thus of several unrelated lineages.
Arsinoitherium is an extinct genus of paenungulate mammals belonging to the extinct order Embrithopoda. It is related to elephants, sirenians, and hyraxes. Arsinoitheres were superficially rhinoceros-like herbivores that lived during the Late Eocene and the Early Oligocene of North Africa from 36 to 30 million years ago, in areas of tropical rainforest and at the margin of mangrove swamps. A species described in 2004, A. giganteum, lived in Ethiopia about 27 million years ago.
Archaeoceti, or Zeuglodontes in older literature, is a paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene. Representing the earliest cetacean radiation, they include the initial amphibious stages in cetacean evolution, thus are the ancestors of both modern cetacean suborders, Mysticeti and Odontoceti. This initial diversification occurred in the shallow waters that separated India and Asia 53 to 45 mya, resulting in some 30 species adapted to a fully oceanic life. Echolocation and filter-feeding evolved during a second radiation 36 to 35 mya.
Arsinoitheriidae is a family of mammals belonging to the extinct order Embrithopoda. Remains have been found in the Middle East, Africa, Asia and Romania. When alive, they would have borne a strong but superficial resemblance to modern rhinoceroses; however, they were not closely related to them, instead being more closely related to hyraxes, elephants, sirenians, and possibly desmostylians.
Plesiadapidae is a family of plesiadapiform mammals related to primates known from the Paleocene and Eocene of North America, Europe, and Asia. Plesiadapids were abundant in the late Paleocene, and their fossils are often used to establish the ages of fossil faunas.
Ptolemaiida is a taxon of wolf-sized afrothere mammals that lived in northern and eastern Africa during the Paleogene. The oldest fossils are from the latest Eocene strata of the Jebel Qatrani Formation, near the Fayum oasis in Egypt. A tooth is known from an Oligocene-aged stratum in Angola, and Miocene specimens are known from Kenya and Uganda.
Altiatlasius is an extinct genus of mammal, which may have been the oldest known primate, dating to the Late Paleocene from Morocco. The only species, Altiatlasius koulchii, was described in 1990.
Palaeoamasia is an extinct herbivorous paenungulate mammal of the embrithopod order, making it distantly related to elephants, sirenians, and hyraxes. Palaeoamasia fossils have been found in Turkish deposits of the Çeltek Formation, dating to the Ypresian. It has unique bilophodont upper molars, an embrithopod synapomorphy.
Crivadiatherium is an extinct genus of Palaeoamasiidae, which fossil remains—teeth and mandible fragments—have been discovered in the Crivadia site in the Hațeg depression, Romania. The age of the Crivadia site is not clear, but seems to be between the Late Eocene to the Early Oligocene. The teeth of Crivadiatherium, compared with those of its relatives as Palaeoamasia from Turkey and Arsinoitherium from Egypt, shows features more primitive, with lower molars without lobes and less bilophodont. It is probable that Crivadiatherium lived in lacustrine environments, maybe eating abrasive plants.
Hypsamasia is an extinct embrithopod mammal that lived during the middle Eocene. Dental remains of this herbivore have been found in the Kartal Formation near the village Saribeylar north of Ankara in what is today Anatolia.
Remingtonocetidae is a diverse family of early aquatic mammals of the order Cetacea. The family is named after paleocetologist Remington Kellogg.
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.
Hyopsodontidae is an extinct family of primitive mammals, initially assigned to the order Condylarthra, living from the Paleocene to the Eocene in North America and Eurasia. Condylarthra is now thought to be a wastebasket taxon; hyopsodontids have occasionally been speculated to be related to Afrotheria, but the most recent consensus is that they are related to Perissodactyla. Analysis of the inner ear shows shared characteristics with the Equoidea ; they may be a basal ungulate group near to perissodactyls.
Phenacodontidae is an extinct family of large herbivorous mammals traditionally placed in the “wastebasket taxon” Condylarthra, which may instead represent early-stage perissodactyls. They lived from the late early Paleocene to early middle Eocene and their fossil remains have been found in North America and Europe. The only unequivocal Asian phenacodontid is Lophocion asiaticus.
Altungulata or Pantomesaxonia is an invalid clade (mirorder) of ungulate mammals comprising the perissodactyls, hyracoids, and tethytheres.
Palaeoamasiidae or Palaeoamasinae is an extinct taxon of embrithopod mammals that have been found in Romania and Anatolia where they lived on the shores of the Tethys Ocean.
The Lignites de Soissonais is a geologic formation in the Var, Marne departments of France. It preserves fossils dating back to the Ypresian stage of the Eocene period.