Xenocyon

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Xenocyon
Temporal range: Pliocene to Middle Pleistocene
Canis cf falconeri.JPG
Canis (Xenocyon) falconeri skull
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Canis
Subgenus: Xenocyon
Kretzoi, 1938[1]

Xenocyon ("strange wolf") is an extinct subgenus of Canis.[2] The group includes Canis (Xenocyon) africanus, Canis (Xenocyon) antonii, and Canis (Xenocyon) falconeri that gave rise to Canis (Xenocyon) lycanoides.[2] The hypercarnivore Xenocyon gave rise to the modern dhole and the African hunting dog.[3]:p149

Taxonomy

Xenocyon is proposed as a subgenus of Canis named Canis (Xenocyon).[2] One taxonomic authority proposes that as part of this sub-genus, the group named Canis (Xenocyon) ex gr. falconeri (ex gr. meaning "of the group including") would include all of the large hypercarnivorous canids that inhabited the Old World during the Late Pliocene–Early Pleistocene: Canis (Xenocyon) africanus in Africa, Canis (Xenocyon) antonii in Asia, and Canis (Xenocyon) falconeri in Europe. Further, these three could be regarded as extreme geographical variations within the one taxon. This group was hypercanivorous, had a large body size that is comparable with the northern populations of the modern gray wolf (Canis lupus), and are characterized by a short neurocranium relative to their skull size.[2]

Canids have five toes on their forelimbs. By the Early Pleistocene this lineage had developed four digits on their forelimbs, which is the characteristic feature of the modern African hunting dog (Lycaon pictus).[4][5] The African hunting dog cannot be positively identified in the fossil record of eastern Africa until the middle Pleistocene,[6] and identifying the oldest Lycaon fossil is difficult because these are hard to distinquish from Canis (Xenocyon) africanus.[5] Some authors consider Canis (Xenocyon) lycanoides as ancestral of both genus Lycaon and genus Cuon.[7][8][9][3]:p149 Therefore, one taxonomic authority has proposed that all of the Canis (Xenocyon) group should be reclassified into genus Lycaon. This would form three chrono-species, with would include Lycaon falconeri during the Late Pliocene of Eurasia, Lycaon lycaonoides during the Early-Middle Pleistocene of Eurasia and Africa, and Lycaon pictus during the Middle–Late Pleistocene and the extant African form.[4]

Canis (Xenocyon) africanus

The species was originally named Canis africanus (Pohle 1928)[10] but was later reassigned as Canis (Xenocyon) africanus. It existed during the Late Pliocene and Early Pleistocene of Africa.[2]

Canis (Xenocyon) antonii

The species was originally named Canis antonii (Zdansky 1924)[11] but was later reassigned as Canis (Xenocyon) antonii. It existed during the late Pliocene and Early Pleistocene of Asia.[2] The name was applied to Late Pliocene fossils of canids with hypercarnivorous dentition that were found in China at the sites Loc. 33 (Yang Shao Tsun in Henan Provicne), Loc. 64 (Chihli Province). and Fan Tsun (Shansi Province).[12] The species was recorded in Europe as Canis (Xenocyon) falconeri.[4]

Canis (Xenocyon) falconeri

Upper Valdarno is the name given to that part of the Arno valley situated in the provinces of Florence and Arezzo, Italy. The region is bounded by the Pratomagno mountain range to the north and east and by the Chianti mountains to the south and west. The Upper Valdarno Basin has provided the remains of three fossil canid species dated to the Late Villafranchian era of Europe 1.9-1.8 million years ago that arrived with a faunal turnover around that time (Early Pleistocene). It is here that the Swiss paleontologist Charles Immanuel Forsyth Major discovered the Falconer's wolf Canis falconeri (Forsyth Major 1877).[13] The species was later reassigned as Canis (Xenocyon) falconeri,[2] but was later regarded as the European arrival of Canis (Xenocyon) antonii.[4] The species gave rise to Canis (Xenocyon) lycanoides.[2]

Canis (Xenocyon) lycaonoides

mandible

The species was originally named Xenocyon lycaonoides (Kretzoi 1938)[1] but was later reassigned as Canis (Xenocyon) lycanoides.[2] It existed from the Early Pleistocene to the Middle Pleistocene in Africa and Eurasia.[4] The diversity of the wolf-sized species decreased by the end of the Early Pleistocene and into the Middle Pleistocene of Europe and Asia. These wolves include the large hypercarnivorous Canis (Xenocyon) lycaonoides that was comparable in size with the modern gray wolf (C. lupus) northern populations, and the small wolf C. mosbachensis/C. variabilis that is comparable in size to the modern Indian wolf. Both types of wolves could be found existing from England and Greece across Europe to the high latitudes of Siberia through to Transbaikalia, Tajikistan, Mongolia, and China. The true gray wolves did not make an appearance until the end of the Middle Pleistocene 500-300 thousand years ago.[12]

It preyed on antelope, deer, elephant calves, aurochs, baboons, wild horse, and possibly humans. It was probably the ancestor of the African wild dog (Lycaon pictus) and possibly the dhole (Cuon alpinus) of south-east Asia, the extinct Sardinian dhole (Cynotherium sardous),[4][14][7] and perhaps the extinct Javanese dogs (Megacyon merriami, Mececyon trinilensis).[15][16]

Just before the appearance of the dire wolf (Canis dirus), North America was invaded by the genus Xenocyon, which was as large as C. dirus and more hypercarnivorous. The fossil record shows them as rare and it is assumed that they could not compete with the newly derived C. dirus.[3]

References

  1. ^ a b Kretzoi, M. 1938. Die Raubtiere von Gombaszög nebst einer Übersicht der Gesamtfauna. Annales Museum Nationale Hungaricum 31: 89–157.
  2. ^ a b c d e f g h i Rook, L. 1994. The Plio-Pleistocene Old World Canis (Xenocyon) ex gr. falconeri. Bolletino della Società Paleontologica Italiana 33:71–82.
  3. ^ a b c Wang, Xiaoming; Tedford, Richard H.; Dogs: Their Fossil Relatives and Evolutionary History. New York: Columbia University Press, 2008.
  4. ^ a b c d e f Martínez-Navarro, B. & L. Rook (2003). "Gradual evolution in the African hunting dog lineage: systematic implications". Comptes Rendus Palevol. 2 (8): 695–702. doi:10.1016/j.crpv.2003.06.002. 
  5. ^ a b Creel, Scott; Creel, Nancy Marusha (2002). The African Wild Dog: Behavior, Ecology, and Conservation. Princeton University Press, New Jersey. p. 3. ISBN 0-691-01655-0. 
  6. ^ Werdelin, L.; Lewis, M.E. (2005). "Plio-Pleistocene Carnivora of eastern Africa: species richness and turnover patterns". Zoological Journal of the Linnean Society. 144 (2): 121–144. doi:10.1111/j.1096-3642.2005.00165.x. 
  7. ^ a b Moulle, P.E.; Echassoux, A.; Lacombat, F. (2006). "Taxonomie du grand canidé de la grotte du Vallonnet (Roquebrune-Cap-Martin, Alpes-Maritimes, France)". L'anthropologie. 110 (5): 832–836. doi:10.1016/j.anthro.2006.10.001. Retrieved 2008-04-28.  (in French)
  8. ^ Baryshnikov, Gennady F. "Pleistocene Canidae (Mammalia, Carnivora) from the Paleolithic Kudaro caves in the Caucasus." Russian Journal of Theriology 11.2 (2012): 77-120.
  9. ^ Cherin, Marco; Bertè, Davide F.; Rook, Lorenzo; Sardella, Raffaele (2013). "Re-Defining Canis etruscus (Canidae, Mammalia): A New Look into the Evolutionary History of Early Pleistocene Dogs Resulting from the Outstanding Fossil Record from Pantalla (Italy)". Journal of Mammalian Evolution. 21: 95. doi:10.1007/s10914-013-9227-4. 
  10. ^ Pohle H., 1928. Die Raubtiere von Oldoway. Wissenschaftliche Ergebnisse der Oldoway-Expedition 1913 (N F) 3: 45–54.
  11. ^ O. Zdansky, Jungtertiäre Carnivoren Chinas, Paleontol. Sin., ser. C II (1) (1924) 38–45.
  12. ^ a b Sotnikova, M (2010). "Dispersal of the Canini (Mammalia, Canidae: Caninae) across Eurasia during the Late Miocene to Early Pleistocene". Quaternary International. 212 (2): 86–97. doi:10.1016/j.quaint.2009.06.008. 
  13. ^ Forsyth Major CI (1877) Considerazioni sulla fauna dei Mammiferi pliocenici e postpliocenici della Toscana. III. Cani fossili del Val d’Arno superiore e della Valle dell’Era. Mem Soc Tosc Sci Nat 3:207–227
  14. ^ Lyras, G.A.; Van Der Geer, A.E.; Dermitzakis, M.; De Vos, J. (2006). "Cynotherium sardous, an insular canid (Mammalia: Carnivora) from the Pleistocene Of Sardinia (Italy), and its origin". Journal of Vertebrate Paleontology. 26 (3): 735–745. doi:10.1671/0272-4634(2006)26[735:CSAICM]2.0.CO. 
  15. ^ Lyras, G.A.; Van Der Geer, A.E.; Rook, L. (2010). "Body size of insular carnivores: evidence from the fossil record". Journal of Biogeography. 37 (6): 1007–1021. doi:10.1111/j.1365-2699.2010.02312.x. 
  16. ^ Van der Geer, A.; Lyras, G.; De Vos, J.; Dermitzakis M. (2010). Evolution of Island Mammals: adaptation and extinction of placental mammals on islands. Wiley-Blackwell (Oxford, UK). ISBN 978-1-4051-9009-1. 
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