Amphicynodontidae

{{confused|Amphicyonidae}}

{{Short description|Extinct clade of mammals}}

{{Use dmy dates|date=August 2019}}

{{Automatic taxobox

| image = Kolponomos NT.jpg

| image_caption = Artist's restoration of Kolponomos newportensis.

| fossil_range = Late Eocene to Early Miocene
{{Fossil range|38|18}}

| taxon = Amphicynodontidae

| authority = Simpson, 1945

| subdivision_ranks = Genera

| subdivision =

• †Allocyon
• †Amphicticeps
• †Amphicynodon
• †Drassonax
• †Kolponomos
• †Pachycynodon
• †Wangictis

}}

Amphicynodontidae is a probable clade of extinct arctoids. While some researchers consider this group to be an extinct subfamily of bears,{{cite journal | last1 = McLellan | first1 = B. | last2 = Reiner | first2 = D.C. |year=1992 |title= A review of bear evolution |journal= International Association for Bear Research and Management |volume=9 |issue=1 |pages=85–96 |doi=10.2307/3872687| jstor = 3872687 | s2cid = 91124592 | url = https://pdfs.semanticscholar.org/a5db/fd5dd863f9d68bc07d99e5bea2a4540647ab.pdf | archive-url = https://web.archive.org/web/20200219120709/https://pdfs.semanticscholar.org/a5db/fd5dd863f9d68bc07d99e5bea2a4540647ab.pdf | url-status = dead | archive-date = 2020-02-19 }} a variety of morphological evidence links amphicynodontines with pinnipeds, as the group were semi-aquatic otter-like mammals.{{Cite journal | last1 = Tedford | first1 = R. H. | author-link = Richard H. Tedford | last2 = Barnes | first2 = L. G. | last3 = Ray | first3 = C. E. | title = The early Miocene littoral ursoid carnivoran Kolponomos: Systematics and mode of life | year = 1994 | journal = Proceedings of the San Diego Society of Natural History | volume = 29 | pages = 11–32 | url = https://www.biodiversitylibrary.org/pdf1/000389400021705.pdf | access-date = 24 July 2010 | archive-url=https://web.archive.org/web/20120922142556/http://www.biodiversitylibrary.org/pdf1/000389400021705.pdf | archive-date=2012-09-22 }}{{cite journal | last1=Rybczynski|first1=N. | last2=Dawson|first2=M.R. | last3=Tedford|first3=R.H. | year = 2009 | title = A semi-aquatic Arctic mammalian carnivore from the Miocene epoch and origin of Pinnipedia | journal = Nature | volume = 458 | issue = 7241 | pages = 1021–24 | doi = 10.1038/nature07985 | pmid = 19396145|bibcode=2009Natur.458.1021R |s2cid=4371413 }}{{cite journal | last1=Berta|first1=A. | last2=Morgan|first2=C. | last3=Boessenecker|first3=R.W. | year = 2018 | title = The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses | journal = Annual Review of Earth and Planetary Sciences | volume = 46 | pages = 203–228 | doi = 10.1146/annurev-earth-082517-010009|bibcode=2018AREPS..46..203B | doi-access=free }} In addition to the support of the pinniped–amphicynodontine clade, other morphological and some molecular analyses support bears being the closest living relatives to pinnipeds.{{cite journal|author1=Hunt, R. M. Jr. |author2=Barnes, L. G. |year=1994|title=Basicranial evidence for ursid affinity of the oldest pinnipeds|journal=Proceedings of the San Diego Society of Natural History|volume=29|pages=57–67|url=https://archive.org/details/cbarchive_36692_basicranialevidenceforursidaff1990|format=PDF}}{{cite journal |author1=Lento, G. M. |author2=Hickson, R. E. |author3=Chambers, G. K. |author4=Penny, D. |year=1995 |title=Use of spectral analysis to test hypotheses on the origin of pinnipeds |journal=Molecular Biology and Evolution |volume=12 |issue=1 |pages=28–52 |pmid=7877495 |doi=10.1093/oxfordjournals.molbev.a040189|doi-access=free }}{{Cite journal |author1=Wang, X. |author2=McKenna, M. C. |author3=Dashzeveg, D. |title=Amphicticeps and Amphicynodon (Arctoidea, Carnivora) from Hsanda Gol Formation, central Mongolia and phylogeny of basal arctoids with comments on zoogeography. |doi=10.1206/0003-0082(2005)483[0001:AAAACF]2.0.CO;2 |journal=American Museum Novitates |issue=3483 |page=216 |year=2005|hdl=2246/5674 |url=https://zenodo.org/record/4735171 }}{{Cite journal |author1=Higdon, J. W. |author2=Bininda-Emonds, O. R. |author3=Beck, R. M. |author4=Ferguson, S. H. |title=Phylogeny and divergence of the pinnipeds (Carnivora: Mammalia) assessed using a multigene dataset |doi=10.1186/1471-2148-7-216 |journal=BMC Evolutionary Biology |volume=7 |page=216 |year=2007 |pmid=17996107 |pmc=2245807 |doi-access=free }} According to McKenna and Bell (1997) Amphicynodontinae are classified as stem-pinnipeds in the superfamily Phocoidea.{{cite book | last1 = McKenna | first1 = M.C. | last2 = Bell | first2 = S. | year = 1997 | title = Classification of Mammals Above the Species Level. | publisher = Columbia University Press, New York}} Fossils of these mammals have been found in Europe, North America and Asia. Amphicynodontines should not be confused with Amphicyonids (bear-dogs), a separate family of Carnivora which is a sister clade to arctoids within the caniforms, but which may be listed as a clade of extinct arctoids in older publications.