{{Short description|Extinct family of mammals}} {{Automatic taxobox | fossil_range = Early Oligocene to Miocene, {{Fossil range|33.9|7.2}} | image = Desmostylus ROM.jpg | image_caption = ''Desmostylus'', Royal Ontario Museum | taxon = Desmostylidae | authority = {{Harvnb|Osborn|1905}} }}
'''Desmostylidae''' is an extinct family of herbivorous marine mammals belonging to the order of Desmostylia. They lived in the coastal waters of the northern Pacific Ocean from the Early Oligocene (Rupelian) through the Late Miocene (Tortonian) (33.9 mya—7.2 MYA),<ref name="Paleodb43291">{{Paleodb|43291|Desmostylidae}}. Retrieved April 2020.</ref><ref name="K. Chiba, A. R 2016">K. Chiba, A. R. Fiorillo, L. L. Jacobs, Y. Kimura, Y. Kobayashi, N. Kohno, Y. Nishida, M. J. Polcyn, and K. Tanaka. 2016. A new desmostylian mammal from Unalaska (USA) and the robust Sanjussen jaw from Hokkaido (Japan), with comments on feeding in derived desmostylids. Historical Biology 28(1-2):289-303</ref> existing for approximately {{Mya|33.9-7.2|million years}}.
==Taxonomy and systematics== Desmostylidae was named by {{Harvnb|Osborn|1905}} and assigned to the order Desmostylia by McKenna and Bell in 1997.<ref name="Paleodb43291"/>
{{Harvnb|Cockburn|Beatty|2009}} found a subadult specimen of ''Behemotops proteus'' on Vancouver Island in 2007. They noted that the cranial features of their specimen were similar to those of ''Cornwallius'' and that the adult dentition was not delayed in their specimen, unlike in ''Desmostylus'' and other Afrotheria, and they concluded that Desmostylidae and Paleoparadoxiidae probably diverged earlier than previously believed and that delayed dentition can not be the most primitive state of Desmostylia.<ref>{{Harvnb|Cockburn|Beatty|2009|loc=Abstract}}</ref>
== Ichnology == Trace fossils most likely produced by desmostylids are known in the form of ''Piscichnus waitemata'' from the Shirahama Formation of Japan. They were likely made by desmostylids using their oral pump to generate water flows while foraging.<ref>{{Cite journal |last1=Nara |first1=Masakazu |last2=Imai |first2=Satoru |last3=Fujino |first3=Shigehiro |date=26 September 2025 |title=Well-preserved Piscichnus waitemata in tidal-flat deposits of the Miocene Shirahama Formation, southwestern Japan and its ichnological, palaeoecological, and palaeontological implications |url=https://www.tandfonline.com/doi/full/10.1080/10420940.2025.2565208#abstract |journal=Ichnos |language=en |pages=1–9 |doi=10.1080/10420940.2025.2565208 |issn=1042-0940 |access-date=2 October 2025 |via=Taylor and Francis Online|url-access=subscription }}</ref>
==Classification== Classification after Chiba 2016:<ref name="K. Chiba, A. R 2016"/> * {{Extinct}}'''Desmostylidae''': ** {{Extinct}}''Cornwallius'' ** {{Extinct}}''Behemotops'' ** {{Extinct}}''Desmostylus'' ** {{Extinct}}''Kronokotherium'' ** {{Extinct}}''Ounalashkastylus''
==References== {{Reflist}} {{Refbegin}} * {{Cite journal | last1 = Cockburn | first1 = Thomas | last2 = Beatty | first2 = Brian | title = A Partial Skeleton of ''Behemotops'' (Desmostylia, Mammalia) from Vancouver Island, British Columbia | year = 2009 | journal = Journal of Vertebrate Paleontology | volume = 29 | issue = 3, Supplement | url = http://www.aragosaurus.com/secciones/publicaciones/artic/Company_etal_2009c_1.pdf | access-date = 9 May 2020 | doi = 10.1080/02724634.2009.10411818 }}<!-- {{Harvnb|Cockburn|Beatty|2009}} --> * {{Cite book | last1 = McKenna | first1 = Malcolm C. | last2 = Bell | first2 = Susan K. | title = Classification of Mammals Above the Species Level | year = 1997 | publisher = Columbia University Press | location = New York | isbn = 0231110138 | oclc = 37345734 }}<!-- {{Harvnb|McKenna|Bell|1997}} --> * {{Cite journal | last = Osborn | first = H. F. | authorlink = Henry Fairfield Osborn | title = Ten years progress in the mammalian Palaeontology of North America | year = 1905 | journal = Extrait des Comptes rendus du 6e Congres international de Zoologie. Session de Berne 1904 | pages = 86–113 | oclc = 18502464 }}<!-- {{Harvnb|Osborn|1905}} --> {{Refend}}
{{Portal|Paleontology}} {{Paenungulata}} {{Taxonbar|from=Q5264837}}
Category:Desmostylians Category:Oligocene mammals Category:Miocene mammals Category:Tortonian extinctions Category:Rupelian first appearances Category:Prehistoric mammal families
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