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Amphicyonidae

This article is about the extinct family of mammals. For the breeds of domestic dog, see Karelian Bear Dog and Tahltan Bear Dog. For dog bears, see Hemicyoninae.

Amphicyonidae is an extinct family of terrestrial carnivorans belonging to the suborder Caniformia. They first appeared in North America in the middle Eocene (around 45 mya), spread to Europe by the late Eocene (35 mya), and further spread to Asia and Africa by the early Miocene (23 mya). They had largely disappeared worldwide by the late Miocene (5 mya), with the latest recorded species at the end of the Miocene in Africa. They were among the first carnivorans to evolve large body size. Amphicyonids are colloquially referred to as "bear-dogs".[1]

Amphicyonids
Temporal range: Middle Eocene – Late Miocene
Skeleton of Amphicyon
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Superfamily: †Amphicyonoidea
Family: †Amphicyonidae
Haeckel, 1866
Subfamilies

†Amphicyoninae
†Daphoeninae
†Haplocyoninae
†Temnocyoninae
†Thaumastocyoninae

Taxonomy

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Restoration of Amphicyon ingens

The family was erected by Haeckel in 1866 (also attributed to Trouessart 1885). Their exact position has long been disputed. Some early paleontologists defined them as members of the family Canidae, but the modern consensus is that they form their own family. Some researchers have defined it as the sister clade to ursids (bears), based on morphological analysis of the ear region.[2][1] However, cladistic analysis and reclassification of several species of early carnivore as amphicyonids has strongly suggested that they may be basal caniforms, from lineages older than the origin of both bears and dogs.[3][4][5]

Description

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Amphicyonids ranged in size from as small as 5 kg (11 lb) and as large as 100 to 773 kg (220 to 1,704 lb)[6] and evolved from wolf-like to bear-like body forms.[7]

Early amphicyonids, such as Daphoenodon, possessed a digitigrade posture and locomotion (walking on their toes), while many of the later and larger species were plantigrade or semiplantigrade.[8] The amphicyonids were obligate carnivores, unlike the Canidae, which are hypercarnivores or mesocarnivores.[9]

There is often some confusion with the similar looking (and similarly named) "dog-bears", a more derived group of caniforms that is sometimes classified as a family (Hemicyonidae), but is more often considered a primitive subfamily of ursids (Hemicyoninae).

Evolution

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Map showing the geographic range of Amphicyonidae

It has long been uncertain where amphicyonids originated. It was thought that they may have crossed from Europe to North America during the Miocene epoch, but recent research suggests a possible North American origin from the miacids Miacis cognitus and M. australis (now renamed as the genera Gustafsonia and Angelarctocyon, respectively). As these are of North American origin, but appear to be early amphicyonids, it may be that the Amphicyonidae actually originates in North America.[3]

Other New World amphicyonids include the oldest known amphicyonid, Daphoenus (37–16 Mya).

Amphicyonids began to decline in the late Miocene, and disappeared by the end of the epoch. The exact reasons for this are unclear. The most recent known amphicyonid remains are teeth known from the Dhok Pathan horizon, northern Pakistan, dating to 7.4-5.3 mya.[10] The species is classically named Arctamphicyon lydekkeri, which may actually be synonymous with a species of Amphicyon.[11]

Fossils of juvenile Agnotherium, Ischyrocyon, and Magericyon all show an unusual type of tooth eruption in which there is a vulnerable stage at about two or three years of age where the subadult animal has no functional molar or carnassial teeth, the only functional cheek teeth being several milk premolars.[12] This period was suggested to be "presumably short" but would have made it very difficult for the animal to process food.[13] This type of tooth replacement is not seen in similar carnivorans like ursids or canids, and may have been one factor in the extinction of the Amphicyonidae.

Classification

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Family Amphicyonidae

Not assigned to a subfamily Subfamily Amphicyoninae Subfamily Haplocyoninae
(Eurasia)[14][15] 		Subfamily Daphoeninae
(North America) 		Subfamily Temnocyoninae
(North America)[16] 		Subfamily Thaumastocyoninae[17]

References

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  1. ^ a b Wang, Xiaoming and Richard H. Tedford (2008). Dogs; their Fossil Relatives and Evolutionary History. Columbia University Press. pp. 10–11. ISBN 9780231135283.
  2. ^ Hunt Jr., Robert M. (2001). "Small Oligocene Amphicyonids from North America (Paradaphoenus, Mammalia, Carnivora)". American Museum Novitates (3331): 1–20. doi:10.1206/0003-0082(2001)331<0001:SOAFNA>2.0.CO;2. ISSN 0003-0082. S2CID 198160461. Archived from the original on 2023-09-04. Retrieved 2023-07-06.
  3. ^ a b Tomiya, Susumu; Tseng, Zhijie Jack (2016). "Whence the beardogs? Reappraisal of the Middle to Late Eocene 'Miacis' from Texas, USA, and the origin of Amphicyonidae (Mammalia, Carnivora)". Royal Society Open Science. 3 (10): 160518. Bibcode:2016RSOS....360518T. doi:10.1098/rsos.160518. PMC 5098994. PMID 27853569. Archived from the original on 2016-10-14. Retrieved 2016-10-13.
  4. ^ Hunt, Robert M. Jr. (2004). "Global Climate and the Evolution of Large Mammalian Carnivores during the Later Cenozoic in North America" (PDF). Cenozoic Carnivores and Global Climate. pp. 139–285. doi:10.1206/0003-0090(2004)285<0139:C>2.0.CO;2. S2CID 86236545. Archived from the original (PDF) on July 20, 2007. {{cite book}}: |journal= ignored (help)
  5. ^ Morlo, Michael; Miller, Ellen R.; El-Barkooky, Ahmed N. (2007). "Creodonta and Carnivora from Wadi Moghra, Egypt". Journal of Vertebrate Paleontology. 27 (1): 145–159. doi:10.1671/0272-4634(2007)27[145:CACFWM]2.0.CO;2. ISSN 0272-4634. S2CID 86235694.
  6. ^ Sorkin, B. 2008: A biomechanical constraint on body mass in terrestrial mammalian predators. Lethaia, Vol. 41, pp. 333–347.
  7. ^ Jacobs, Louis L. Jacobs; Scott, Kathleen Marie: Evolution of Tertiary Mammals of North America: Terrestrial carnivores, Cambridge University Press, 1998
  8. ^ Wang, Xiaoming and Tedford, Richard H. Dogs: Their Fossil Relatives and Evolutionary History. New York: Columbia University Press, 2008. p10-11, 29
  9. ^ Hunt, R. M. Jr. (1998). "Amphicyonidae". In Janis, Christine M.; Scott, Kathleen M.; Jacobs, Louis L. (eds.). Evolution of Tertiary Mammals of North America, volume 1: Terrestrial carnivores, ungulates, and ungulatelike mammals. Cambridge, England: Cambridge University Press. pp. 196–227. ISBN 978-0-521-35519-3.
  10. ^ Sehgal, R. K. and A. C. Nanda (2002). "Age of the fossiliferous Siwalik sediments exposed in the vicinity of Nurpur, District Kangra, Himachal Pradesh". Current Science. 82 (4): 392–395. JSTOR 24106648.
  11. ^ Stéphane Peigné (2006). "A new amphicyonid (Mammalia, Carnivora, Amphicyonidae) from the late middle Miocene of northern Thailand and a review of the amphicyonine record in Asia". Thailand Journal of Asian Earth Sciences. 26 (5): 519–532. Bibcode:2006JAESc..26..519P. doi:10.1016/j.jseaes.2004.11.003.
  12. ^ Morlo, Michael; Bastl, Katharina; Habersetzer, Jörg; Engel, Thomas; Lischewsky, Bastian; Lutz, Herbert; von Berg, Axel; Rabenstein, Renate; Nagel, Doris (3 September 2019). "The apex of amphicyonid hypercarnivory: solving the riddle of Agnotherium antiquum Kaup, 1833 (Mammalia, Carnivora)". Journal of Vertebrate Paleontology. 39 (5): e1705848. Bibcode:2019JVPal..39E5848M. doi:10.1080/02724634.2019.1705848. S2CID 214431583.
  13. ^ Morlo, Michael; Bastl, Katharina; Habersetzer, Jörg; Engel, Thomas; Lischewsky, Bastian; Lutz, Herbert; von Berg, Axel; Rabenstein, Renate; Nagel, Doris (3 September 2019). "The apex of amphicyonid hypercarnivory: solving the riddle of Agnotherium antiquum Kaup, 1833 (Mammalia, Carnivora)". Journal of Vertebrate Paleontology. 39 (5): e1705848. Bibcode:2019JVPal..39E5848M. doi:10.1080/02724634.2019.1705848. S2CID 214431583.
  14. ^ a b Jiangzuo, Q.; Wang, S.; et al. (September 2019). "New material of Gobicyon (Carnivora, Amphicyonidae, Haplocyoninae) from northern China and a review of Aktaucyonini evolution". Papers in Palaeontology. 7 (1): 307–327. doi:10.1002/spp2.1283. S2CID 204264754.
  15. ^ Morales, J.; Abella, J.; et al. (May 2021). "Ammitocyon kainos gen. et sp. nov., a chimerical amphicyonid (Mammalia, Carnivora) from the late Miocene carnivore traps of Cerro de los Batallones (Madrid, Spain)". Journal of Systematic Palaeontology. 19 (5): 393–415. doi:10.1080/14772019.2021.1910868. S2CID 235363054. Archived from the original on 2023-04-06. Retrieved 2023-02-18.
  16. ^ Hunt, Robert (2011-01-01). "Evolution of large carnivores during the mid-Cenozoic of North America: The Temnocyonine Radiation (Mammalia, Amphicyonidae)". Papers in the Earth and Atmospheric Sciences. Archived from the original on 2023-03-26. Retrieved 2023-04-07.
  17. ^ Morales, J.; Fejfar, O.; Heizmann, E.; Wagner, J.; Valenciano, A.; Bella, J. (2019). "A new Thaumastocyoninae (Amphicyonidae, Carnivora) from the early Miocene of Tuchořice, the Czech Republic" (PDF). Fossil Imprint. 75 (3–4): 397–411. doi:10.2478/if-2019-0025. S2CID 210921722. Archived (PDF) from the original on 2022-08-14.
  18. ^ Berger, Jean-Pierre (June 1998). "'Rochette' (Upper Oligocene, Swiss Molasse): a strange example of a fossil assemblage". Review of Palaeobotany and Palynology. 101 (1–4): 95–110. Bibcode:1998RPaPa.101...95B. doi:10.1016/S0034-6667(97)00071-7.
  19. ^ a b c d e Fournier, Morgane; Ladevèze, Sadrine; Le Verger, Kévin; Fischer, Valentin; Speijer, Robert P.; Solé, Floréal (2020). "On the morphology of the astragalus and calcaneus of the amphicyonids (Carnivora, Mammalia) from the Paleogene of Europe: implications for the ecology of the European bear-dogs". Geodiversitas. 42 (18): 305–325. doi:10.5252/geodiversitas2020v42a18. S2CID 220714559.
  20. ^ Ginsburg, Léonard (2002). "Un Amphicyonidae (Carnivora, Mammalia) nouveau du Miocène moyen de Vieux-Collonges (Rhône)". Symbioses (in French). 7: 55–57.
  21. ^ a b c d Peign, Stphane; Salesa, Manuel J.; Antn, Mauricio; Morales, Jorge (2008). "A New Amphicyonine (Carnivora: Amphicyonidae) from the Upper Miocene of Batallones-1, Madrid, Spain". Palaeontology. 51 (4): 943–965. Bibcode:2008Palgy..51..943P. doi:10.1111/j.1475-4983.2008.00788.x. S2CID 55334897.
  22. ^ Solé, Floréal; Fischer, Valentin; Denayer, Julien; Speijer, Robert P.; Fournier, Morgane; Le Verger, Kévin; Ladevèze, Sandrine; Folie, Annelise; Smith, Thierry (2020). "The upper Eocene-Oligocene carnivorous mammals from the Quercy Phosphorites (France) housed in Belgian collections". Geologica Belgica. 24 (1–2): 1–16. doi:10.20341/gb.2020.006. S2CID 224860287.
  23. ^ de Bonis, Louis (2020). "New genus of amphicyonid carnivoran (Mammalia, Carnivora, Amphicyonidae) from the phosphorites of Quercy (France)". Fossil Imprint. 76 (1): 201–208. doi:10.37520/fi.2020.013. S2CID 229196919.
  24. ^ Wang, Xiaoming; Hong-jiang, Wang; Jiangzuo, Qigao (2016). "New record of a haplocyonine amphicyonid in early Miocene of Nei Mongol fills a long-suspected geographic hiatus". Vertebrata PalAsiatica. 54 (1): 21–35.
  25. ^ Morales, Jorge; Pickford, M.; Valenciano, Alberto (2016). "Systematics of African Amphicyonidae, with descriptions of new material from Napak (Uganda) and Grillental (Namibia)". Journal of Iberian Geology. 42 (2): 131–150. doi:10.13039/501100003329. hdl:10261/137042. ISSN 1698-6180. Archived from the original on 2022-11-27. Retrieved 2023-05-01.
  26. ^ Grohé, Camille; de Bonis, Louis; Chaimanee, Yaowalak; Chavasseau, Olivier; Rugbumrung, Mana; Yamee, Chotima; Suraprasit, Kantapon; Gibert, Corentin; Surault, Jérôme; Blondel, Cécile; Jaeger, Jean-Jacques (2020). "The Late Middle Miocene Mae Moh Basin of Northern Thailand: The Richest Neogene Assemblage of Carnivora from Southeast Asia and a Paleobiogeographic Analysis of Miocene Asian Carnivorans". American Museum Novitates (3952): 1–57. doi:10.1206/3952.1. S2CID 219296152. Archived from the original on 2023-05-26. Retrieved 2023-05-18.
  27. ^ Werdelin, Lars; Simpson, Scott W. (2009). "The last amphicyonid (Mammalia, Carnivora) in Africa". Geodiversitas. 31 (4): 775–787. doi:10.5252/g2009n4a775. ISSN 1280-9659. S2CID 73677723.
  28. ^ a b c Morales, Jorge; Pickford, Martin (2022). "The taxonomic status of "Ysengrinia" ginsburgi Morales et al. 1998 (Amphicyonidae, Carnivora) from the basal middle Miocene of Arrisdrift, Namibia" (PDF). Communications of the Geological Survey of Namibia. 24: 1–16. Archived (PDF) from the original on 2023-04-05. Retrieved 2023-05-01 – via Google Scholar.
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  30. ^ Jiangzuo, Qigao; Li, Chunxiao; Wang, Shiqi; Sun, Danhui (2018-11-02). "Amphicyon zhanxiangi, sp. nov., a new amphicyonid (Mammalia, Carnivora) from northern China". Journal of Vertebrate Paleontology. 38 (6): e1539857. Bibcode:2018JVPal..38E9857J. doi:10.1080/02724634.2018.1539857. ISSN 0272-4634. S2CID 91998860. Archived from the original on 2023-12-19. Retrieved 2023-05-09.
  31. ^ Werdelin, Lars (2019). "Middle Miocene Carnivora and Hyaenodonta from Fort Ternan, western Kenya". Geodiversitas. 41 (sp1): 267–283. doi:10.5252/geodiversitas2019v41a6. S2CID 146620949.
  32. ^ Morales, Jorge; Pickford, Martin (2022). "The taxonomic status of "Ysengrinia" ginsburgi Morales et al. 1998 (Amphicyonidae, Carnivora) from the basal middle Miocene of Arrisdrift, Namibia" (PDF). Communications of the Geological Survey of Namibia. 24: 1–16. Archived (PDF) from the original on 2023-04-05. Retrieved 2023-05-01 – via Google Scholar.
  33. ^ Morales; Fejfar; Heizmann; Wagner; Valenciano; Abella (2021). "The Amphicyoninae (Amphicyonidae, Carnivora, Mammalia) Of The Early Miocene From Tuchořice, The Czech Republic". Fossil Imprint. 77 (1): 126–144. doi:10.37520/fi.2021.011. S2CID 245032640. Archived from the original on 2023-04-18. Retrieved 2023-05-01.
  34. ^ Fejfar, O.; Heizmann, E. (October 2015). "An illustrated summary of the lower Miocene carnivores (Mammalia, Carnivora) of Tuchořice, Czech Republic". Historical Biology. 28 (1–2): 316–329. doi:10.1080/08912963.2015.1029923. S2CID 85904748.
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