Biology:Xenocranium

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Short description: Genus of prehistoric burrowing mammals

Xenocranium
Temporal range: 35.8–33.9 Ma
Late Eocene
Xenocranium NT.jpg
Artist reconstruction of
Xenocranium pileorivale
compared to the size of a human hand.
Scientific classification e
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.

Etymology

The name of genus Xenocranium comes from grc ξένος (xénos) 'strange' and from grc κρανίον (krāníon) 'skull', respectively after its unique skull arrangement.

The specific epithet is derived from lat pileus 'hat' and from lat rivalis 'brook', in reference to the nearby township of Hat Creek, Wyoming, United States [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] Lua error: Internal error: The interpreter exited with status 1.

See also

References

  1. 1.0 1.1 1.2 E. H. Colbert (1942) (in en). Edentate from the Oligocene of Wyoming. Academy of Natural Sciences, No. 109. ISBN 978-1-60483-109-2. https://books.google.com/books?id=euLVRenwtEEC. 
  2. Rose, Kenneth D.; Emry, Robert J. (1983). "Extraordinary fossorial adaptations in the oligocene palaeanodonts Epoicotherium and Xenocranium (Mammalia)" (in en). Journal of Morphology 175 (1): 33–56. doi:10.1002/jmor.1051750105. ISSN 1097-4687. PMID 30053775. https://onlinelibrary.wiley.com/doi/abs/10.1002/jmor.1051750105. 
  3. 3.0 3.1 (in en) Postilla. Peabody Museum of Natural History. 1894. https://books.google.com/books?id=U5sfAQAAIAAJ. 
  4. Scott, William Berryman (1913) (in en). A History of Land Mammals in the Western Hemisphere. MacMillan. https://books.google.com/books?id=HbAlAAAAMAAJ. 
  5. Kenneth D. Rose (2008). "Palaeanodonta and Pholidota". in Janis, Christine M; Gunnell, Gregg F; Uhen, Mark D. 9 - Palaeanodonta and Pholidota. pp. 135–146. doi:10.1017/CBO9780511541438.010. ISBN 9780511541438. 
  6. Gaudin, Timothy (2009). "The Phylogeny of Living and Extinct Pangolins (Mammalia, Pholidota) and Associated Taxa: A Morphology Based Analysis". Journal of Mammalian Evolution (Heidelberg, Germany: Springer Science+Business Media) 16 (4): 235–305. doi:10.1007/s10914-009-9119-9. http://web2.utc.edu/~gvv824/Gaudin%20et%20al%202009.pdf. 
  7. 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. 

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Wikidata ☰ Q21369124 entry


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