Xenocranium Temporal range: Eocene Late | |
---|---|
Artist reconstruction of Xenocranium pileorivale compared to the size of a human hand. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | † Palaeanodonta |
Family: | † Epoicotheriidae |
Subfamily: | † Epoicotheriinae |
Genus: | † Xenocranium Colbert, 1942 [1] |
Type species | |
†Xenocranium pileorivale Colbert, 1942 |
Xenocranium ("strange skull") is an extinct monotypic genus of placental mammal from extinct paraphyletic subfamily Epoicotheriinae within extinct paraphyletic family Epoicotheriidae in extinct order Palaeanodonta, that lived in North America during the late Eocene.
The name of genus Xenocranium comes from Ancient Greek ξένος (xénos) 'strange' and from Ancient Greek κρανίον (krāníon) 'skull', respectively after its unique skull arrangement.
The specific epithet is derived from Latin pileus 'hat' and from Latin rivalis 'brook', in reference to the nearby township of Hat Creek, Wyoming, U.S.A. [1]
Xenocranium pileorivale was highly specialized animal that was convergent with the talpids, golden moles and marsupial mole. It possesses many traits indicative of the lifestyle of a subterranean burrower, including small eyes, an upturned snout, muscular arms with large attachment points for the triceps, teres major, and carpal and digital flexor muscles. [2] The dental formula is 0.1.41.1.5. [3]
The holotype of Xenocranium pileorivale was recovered from the Brule Formation, 160 feet below the top of the Oligocene outcrop in the area, [1] which correlates with the Chadronian age to the Orellan age under the NALMA classification. Later on, this layer was found to be from Priabonian age of late Eocene. Further remains have been found in the White River Formation of Nebraska. [3] The animals from these formations constitute the White River Fauna, which included predators like Archaeotherium and Hyaenodon , and a large diversity of herbivorous mammals, such as the archaic horse Mesohippus , the cursorial rhinoceros Hyracodon , and the very common "oreodont" Merycoidodon . [4]
The phylogenetic relationships of genus Xenocranium is shown in the following cladogram: [5] [6] [7]
Ferae |
| †Epoicotherium/Xenocranium clade | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Manis ("spirit") is a genus of South Asian and East Asian pangolins, the Asiatic pangolins, from subfamily Maninae, within family Manidae.
Eomanis is the earliest known true pangolin from extinct family Eomanidae within suborder Eupholidota. It lived during the Eocene in Europe. Eomanis fossils found in the Messel Pit in Germany are very similar in size and anatomy to living pangolins of the genus Manis, indicating that pangolins have remained largely unchanged in morphology and behavior for 50 million years. However, unlike modern pangolins, its tail and legs did not bear scales. According to the stomach contents of the excellently preserved Messel specimens, Eomanis’ diet consisted of both insects and plants.
Metacheiromys is an extinct genus of placental mammals from extinct paraphyletic subfamily Metacheiromyinae within extinct paraphyletic family Metacheiromyidae in extinct order Palaeanodonta, that lived in North America from the early to middle Eocene.
Eurotamandua is an extinct genus of mammal from extinct family Eurotamanduidae that lived during the middle Eocene.
Necromanis is an extinct genus of pangolin from superfamily Manoidea. It lived from the middle Oligocene to middle Miocene in Europe. It was originally placed within family Manidae, but was eventually removed from it as more fossil pholidotids from outside that family were found and studied more extensively. Currently, Necromanis is placed as incertae sedis within the pholidotid superfamily Manoidea, together with the families Manidae and Patriomanidae.
Ernanodon is an extinct genus of placental mammal from extinct family Ernanodontidae within extinct order Palaeanodonta, that lived from the middle to late Paleocene in China and Mongolia.
Epoicotheriidae is an extinct paraphyletic family of insectivorous placental mammals within extinct order Palaeanodonta, that lived in North America, Asia and Europe from the late Paleocene to early Oligocene. Epoicotheriids were fossorial mammals. Late Eocene/early Oligocene genera were highly specialized animals that were convergent with the talpids, golden moles and marsupial mole in the structure of their skulls and forelimbs, and would have had a similar lifestyle as subterranean burrowers.
Escavadodon is an extinct genus of pangolin-like myrmecophagous placental mammals of extinct monotypic family Escavadodontidae within extinct order Palaeanodonta, that lived in North America during the middle Paleocene. It contains a single species, Escavadodon zygus, recovered from the Nacimiento Formation of New Mexico.
Gracilocyon is an extinct paraphyletic genus of placental mammals from clade Carnivoraformes, that lived in North America and Europe from late Paleocene to early Eocene.
The Willwood Formation is a sedimentary sequence deposited during the late Paleocene to early Eocene, or Clarkforkian, Wasatchian and Bridgerian in the NALMA classification.
Patriomanis is an extinct genus of pangolin from extinct family Patriomanidae. It lived from the late Eocene to early Oligocene of North America and it currently represents the only pangolin known from the Western Hemisphere. The genus contains one species, P. americana, which is known from six specimens, mostly from the Chadronian White River Formation of Montana. It had long digits and a prehensile tail, suggesting that it was arboreal, and its jaw was capable of opening wider than modern pangolins. Its ears and the hair between its scales were also longer than modern pangolins.
Palaeanodonta is an extinct clade of stem-pangolins. They were insectivorous (myrmecophagous), possibly fossorial, and lived from the middle Paleocene to early Oligocene in North America, Europe and Asia. While the taxonomic grouping of Palaeanodonta has been debated, it is widely thought that they are a sister group to pangolins.
Patriomanidae is an extinct family of pangolins from superfamily Manoidea that includes two extinct genera Patriomanis and Cryptomanis.
Ernanodontidae is an extinct family of myrmecophagous placental mammals within extinct order Palaeanodonta, that lived in Asia from the middle to late Paleocene.
Pholidotamorpha is a clade of placental mammals from mirorder Ferae that includes the order Pholidota and extinct order Palaeanodonta.
Euromanis is one of the earliest known pangolin genera. It lived during the middle Eocene in Europe. Euromanis fossils found in the Messel Pit in Germany. Unlike modern pangolins, it did not bear scales on its body.
Palaeonictinae is an extinct subfamily of placental mammals from extinct family Oxyaenidae, that lived from the late Paleocene to early Eocene of Europe and North America.
Metacheiromyidae is an extinct paraphyletic family of myrmecophagous placental mammals within extinct order Palaeanodonta, that lived in North America and Europe from the late Paleocene to middle Eocene.
Epoicotheriinae is an extinct paraphyletic subfamily of insectivorous placental mammals within extinct paraphyletic family Epoicotheriidae in extinct order Palaeanodonta, that lived in North America and Europe from the early Eocene to early Oligocene. Epoicotheriins were fossorial mammals. Late Eocene/early Oligocene genera were highly specialized animals that were convergent with the talpids, golden moles and marsupial mole in the structure of their skulls and forelimbs, and would have had a similar lifestyle as subterranean burrowers.
Cryptomanis is an extinct genus of pangolin from extinct family Patriomanidae. The genus is only known from the holotype specimen from middle Eocene deposits from Inner Mongolia, China. The holotype, AMNH 26140, was for years labeled as an unnamed pangolin in the fossil collection for decades. The remains comprise of an incomplete postcranial specimen, with nearly complete hind limbs, an incomplete pelvis, a complete lumbar series from an incomplete vertebral column, numerous fragmentary remains of rib and sternal bones, a fragmentary scapula, and partially preserved forelimbs. Based on the femural length Cryptomanis was comparable in size to the modern Sunda pangolin.
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