Amphicyonidae

Belongs within: Carnivora.

The Amphicyonidae, commonly called bear-dogs, are a group of relatively large carnivorans of somewhat uncertain affinities known from the late Oligocene to late Miocene of Eurasia, Africa and North America (Savage 1978). They are generally agreed to have had caniform affinities, but different authors have placed them closer to dogs, bears or to the Arctoidea clade as a whole (Flynn et al. 1988). The largest amphicyonids are estimated to have reached about 600 kg in weight.

Characters (from Flynn et al. 1988): Skeleton massive; tail long; feet plantigrade, pentadactyl. Skull elongate; premolars simple, low-crowned, elongated, often separated by diastemata; M³ originally present; upper molars with strong lingual cingulum nearly symmetrically disposed around protocone; upper carnassial with anteriorly placed protocone; M₂ with paraconid; lower molar talonids with low entoconid, hypoconid a longitudinal crest more centrally located on talonid. Auditory bulla with small entotympanic, either unossified or consisting mostly of carotid canal; ectotympanic just covering promontorium, not extending posterior to mastoid process. External auditory meatus inflated by extension of hypotympanic sinus.

<==Amphicyonidae
    |  i. s.: Afrocyon burolletiS78
    |         Agnotherium Kaup 1832SM93
    |         Arctamphicyon Pilgrim 1932SM93
    |         Pseudarctos Schlosser 1899SM93
    |         HecubidesS78
    |           |--H. euryodonS78
    |           `--H. macrodonS78
    |         Eosictis avinoffiB96
    |         ‘Miacis’ cognitusH96
    |--Daphoeninae [Daphoenidae]H96
    |    |--Daphoenodon superbusH96, WT08
    |    |--Paradaphoenus minimus (Hough 1948) [=Daphoenus minimus]H96
    |    |--Daphoenus Leidy 1853H96, SM93
    |    |    |--D. hartshornianusV91
    |    |    |--D. lambei Russell 1934 [incl. D. demilo Dawson 1980]H96
    |    |    |--‘Canis’ lippincottianus Cope 1873WT96
    |    |    |--D. nebrascensisD07
    |    |    `--D. vetus Leidy 1854H96
    |    `--+--DaphoenictisH96
    |       `--Brachyrhynchocyon Loomis 1931 [incl. Daphoenocyon Hough 1948]H96
    |            |--B. dodgei (Scott 1898)TPG96, S96 [=Daphoenocyon dodgeiTPG96]
    |            |--B. intermediusV91
    |            `--B. montanus Hunt 1996H96
    `--+--+--HaplocyoninaeH96
       |  `--TemnocyoninaeH96
       |       |--Temnocyon obtusidensV91
       |       `--MammacyonH96
       `--AmphicyoninaeH96
            |--Cynodictis Bravard & Pomel 1850H96, SM93
            `--+--PseudocyonopsisH96
               |--YsengriniaH96
               |--Amphicyon Lartet 1836H96, D07
               |    |--A. giganteusD07
               |    |--‘Mustela’ incertaK54
               |    |--A. longiramusD07
               |    |--A. majorD07
               |    `--A. tairumensisDW04
               `--+--Cynelos caroniavorusH96, V91
                  |--PliocyonH96
                  |--PseudocyonH96
                  `--Ischyrocyon Matthew 1904H96, SM93
                       `--I. gidleyiV91

*Type species of generic name indicated

References

[B96] Bryant, H. N. 1996. Nimravidae. In: Prothero, D. R., & R. J. Emry (eds) The Terrestrial Eocene–Oligocene Transition in North America pp. 453–475. Cambridge University Press.

[DW04] Deng T., Wang X., Ni X. & Liu L. 2004. Sequence of the Cenozoic mammalian faunas of the Linxia Basin in Gansu, China. Acta Geologica Sinica (English Edition) 78 (1): 8–14.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

Hunt, R. M., Jr. 1996. Amphicyonidae. In: Prothero, D. R., & R. J. Emry (eds) The Terrestrial Eocene–Oligocene Transition in North America pp. 476–485. Cambridge University Press.

[K54] Kurtén, B. 1954. The type collection of Ictitherium robustum (Gervais, ex Nordmann) and the radiation of the ictitheres. Acta Zoologica Fennica 86: 1–26.

[S78] Savage, R. J. G. 1978. Carnivora. In: Maglio, V. J., & H. B. S. Cooke (eds) Evolution of African Mammals pp. 249–267. Harvard University Press: Cambridge (Massachusetts).

[S96] Storer, J. E. 1996. Eocene-Oligocene faunas of the Cypress Hills Formation, Saskatchewan. In: Prothero, D. R., & R. J. Emry (eds) The Terrestrial Eocene–Oligocene Transition in North America pp. 240–261. Cambridge University Press.

[SM93] Stucky, R. K., & M. C. McKenna. 1993. Mammalia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 739–771. Chapman & Hall: London.

[TPG96] Tabrum, A. R., D. R. Prothero & D. Garcia. 1996. Magnetostratigraphy and biostratigraphy of the Eocene-Oligocene transition, southwestern Montana. In: Prothero, D. R., & R. J. Emry (eds) The Terrestrial Eocene–Oligocene Transition in North America pp. 278–311. Cambridge University Press.

[V91] Valkenburgh, B. van. 1991. Iterative evolution of hypercarnivory in canids (Mammalia: Carnivora): evolutionary interactions among sympatric predators. Paleobiology 17 (4): 340–362.

[WT96] Wang, X., & R. H. Tedford. 1996. Canidae. In: Prothero, D. R., & R. J. Emry (eds) The Terrestrial Eocene–Oligocene Transition in North America pp. 433–452. Cambridge University Press.

[WT08] Wang, X., & R. H. Tedford. 2008. Dogs: Their fossil relatives and evolutionary history. Columbia University Press: New York.