Hapalodectidae

{{short description|Extinct family of mammals}} {{Automatic taxobox | fossil_range = {{Fossil range|Late Paleocene|Late Eocene}} | image = Hapalodectes_serus.JPG | image_caption = Life restoration of ''Hapalodectes serus'' (bottom) and ''Pachyaena'' | taxon = Hapalodectidae | authority = Szalay & Gould, 1966 | subdivision_ranks = Genera | subdivision = {{Linked genus list |Hapalodectes|Matthew, 1909 |Hapalorestes|Gunnell & Gingerich, 1996 }} }}

'''Hapalodectidae''' (literal translation 'soft biters': {{Transliteration|grc|hapalos}} ('soft, tender'), {{Transliteration|grc|dêktês}} ('biter')) is an extinct family of relatively small-bodied ({{cvt|1|–|8|kg|lb}})<ref name=Gunnell96>{{cite journal|last1=Gunnell|first1=Gregg F.|last2=Gingerich|first2=Philip D.|year=1989|title=New hapalodectid Hapalorestes lovei (Mammalia, Mesonychia) from the early middle Eocene of northwestern Wyoming|journal=Contributions from the Museum of Paleontology|publisher=University of Michigan|volume=29|number=15|pages=413–418|hdl=2027.42/48636}}</ref> mesonychian placental mammals from the Paleocene and Eocene of North America and Asia.<ref name=McK&B>{{cite book|last1=McKenna|first1=Malcolm C.|last2=Bell|first2=Susan K.|date=December 1997|title=Classification of Mammals Above the Species Level|publisher=Columbia University Press|isbn=0-231-11012-X}}</ref> Hapalodectids differ from the larger and better-known mesonychids by having teeth specialized for cutting (presumably meat), while the teeth of other mesonychids, such as ''Mesonyx'' or ''Sinonyx'', are more specialized for crushing bones.<ref name=Gunnell96/> Hapalodectids were once considered a subfamily of the Mesonychidae,<ref name=SzalayGould>{{cite journal|last1=Szalay|first1=Frederick S.|last2=Gould|first2=Stephen Jay|title=Asiatic Mesonychidae (Mammalia, Condylarthra)|journal=Bulletin of the American Museum of Natural History|year=1966|volume=132|pages=127–174|hdl=2246/1112|hdl-access=free}}</ref> but the discovery of a skull of ''Hapalodectes hetangensis'' showed additional differences justifying placement in a distinct family.<ref name=Ting&Li>{{cite journal|last1=Ting|first1=Suyin|last2=Li|first2=Chuankuei|year=1987|title=The skull of Hapalodectes (?Acreodi, Mammalia), with notes on some Chinese Paleocene mesonychids|journal=Vertebrata PalAsiatica|volume=25|pages=161–186|language=zh, en|url=http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/200903/W020090813373380406952.pdf|format=PDF|url-status=live|archive-url=https://web.archive.org/web/20201102220055/http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/200903/W020090813373380406952.pdf|archive-date=2020-11-02}}</ref> In particular, ''H. hetangensis'' has a postorbital bar closing the back of the orbit,<ref name=Ting&Li/> a feature lacking in mesonychids. The postcranial skeletal anatomy of hapalodectids is poorly known, and of the postcranial elements, only the humerus has been described. The morphology of this bone indicates less specialization for terrestrial locomotion than in mesonychids.<ref name=OLeary98>{{cite journal|last=O'Leary|first=Maureen A.|year=1998|title=Morphology of the humerus of Hapalodectes (Mammalia, Mesonychia)|journal=American Museum Novitates|number=3242|pages=1–6|hdl=2246/3175|hdl-access=free}}</ref>

==Taxa== "Hapalodectinae" was originally erected on the basis of ''Hapalodectes'', and, after promotion to family ranking, contained up to five genera based on teeth and jaw fragments with anatomies similar to ''Hapalodectes''. However, as of Ting and Li, 1987, and confirmed with Gunnell and Gingerich, 1996, the genera ''Honanodon'', ''Lohoodon'' and ''Metahapalodectes'' are no longer considered hapalodectids due to the absence of grooves on the lower molars otherwise diagnostic of ''Hapalodectes'' and ''Hapalorestes''.<ref name=gunnellgingerich>Gunnell, Gregg F., and Philip D. Gingerich. "New hapalodectid Hapalorestes lovei (Mammalia, Mesonychia) from the early Middle Eocene of northwestern Wyoming." (1996).</ref>

'''Family Hapalodectidae''' *Genus ''Hapalodectes'' ** ''H. anthracinus'' Zhou et Gingerich, 1991 ** ''H. dux'' Lopatin, 1999 ** ''H. hetangensis'' Ting et Li, 1987 ** ''H. huanghaiensis'' Tong et Wang, 2006 ** ''H. leptognathus'' Osborn et Wortman, 1892 ** ''H. lopatini'' Solé et al., 2017 ** ''H. paleocenus'' Beard et al., 2010 ** ''H. serus'' Matthew et Granger, 1925 *Genus ''Hapalorestes'' **''H. lovei''

==References== {{Reflist}} {{Mesonychia}} {{Taxonbar|from=Q941132}}

Category:Mesonychia Category:Eocene extinctions Category:Paleocene first appearances Category:Prehistoric mammal families