Xenocranium
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.
| Xenocranium Temporal range: Late Eocene | |
|---|---|
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| 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 | |
Etymology
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 from Latin pileus 'hat' and from Latin rivalis 'brook', in reference to the nearby township of Hat Creek, Wyoming, U.S.A.[1]
Description
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]
Palaeoecology
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]
Phylogenetic tree
The phylogenetic relationships of genus Xenocranium is shown in the following cladogram:[5][6][7]
| Ferae |
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†Epoicotherium/Xenocranium clade | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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See also
References
- E. H. Colbert (1942). Edentate from the Oligocene of Wyoming. ISBN 978-1-60483-109-2.
{{cite book}}:|journal=ignored (help) - Rose, Kenneth D.; Emry, Robert J. (1983). "Extraordinary fossorial adaptations in the oligocene palaeanodonts Epoicotherium and Xenocranium (Mammalia)". Journal of Morphology. 175 (1): 33–56. doi:10.1002/jmor.1051750105. ISSN 1097-4687. PMID 30053775. S2CID 51727274.
- Postilla. Peabody Museum of Natural History. 1894.
- Scott, William Berryman (1913). A History of Land Mammals in the Western Hemisphere. MacMillan.
- Kenneth D. Rose (2008). "Palaeanodonta and Pholidota". In Janis, Christine M; Gunnell, Gregg F; Uhen, Mark D (eds.). 9 - Palaeanodonta and Pholidota. pp. 135–146. doi:10.1017/CBO9780511541438.010. ISBN 9780511541438.
- Gaudin, Timothy (2009). "The Phylogeny of Living and Extinct Pangolins (Mammalia, Pholidota) and Associated Taxa: A Morphology Based Analysis" (PDF). Journal of Mammalian Evolution. Heidelberg, Germany: Springer Science+Business Media. 16 (4): 235–305. doi:10.1007/s10914-009-9119-9. S2CID 1773698.
- Kondrashov, Peter; Agadjanian, Alexandre K. (2012). "A nearly complete skeleton of Ernanodon (Mammalia, Palaeanodonta) from Mongolia: morphofunctional analysis". Journal of Vertebrate Paleontology. 32 (5): 983–1001. doi:10.1080/02724634.2012.694319. ISSN 0272-4634. S2CID 86059673.