Content deleted Content added
No edit summary |
|||
| (25 intermediate revisions by 20 users not shown) | |||
Line 1:
{{short description |An extinct family of pig-like omnivores from North America and Eurasia}}
{{Automatic taxobox
| name =
| fossil_range = {{Fossilrange|37.2|15.97}}Late [[Eocene]] - Middle [[Miocene]]
| image = Dinohyus hollandi (fossil mammal) (Harrison Formation, Lower Miocene; Agate Springs Fossil Quarry, Nebraska, USA) 1 (33515247252).jpg
Line 14:
}}
'''Entelodontidae''' is
==Description==
Entelodonts could get quite large, and in many cases are the largest mammals in their respective ecosystems. The largest entelodont known from a complete skeleton was ''[[Daeodon]]'', a North American entelodont which could reach an estimated weight of 750 kg (1650 pounds),<ref name=":3" /> and a height up to {{convert|
{{cite book
| url = https://books.google.com/books?id=MOEtAQAAIAAJ&q=Бенарская+фауна+олигоценовых+позвоночных
Line 37:
Similar to pigs, entelodonts retain a large number of teeth, a [[plesiomorphic]] trait approximating the ancestral condition for artiodactyls. They have a typical mammalian [[dental formula]] of 3.1.4.3 / 3.1.4.3, meaning that each tooth row has three pairs of robust [[Incisor|incisors]], a pair of large [[canine (tooth)|canines]], four pairs of pointed [[Premolar|premolars]], and three pairs of relatively simple and flat [[molar (tooth)|molars]]. This unreduced, or "complete" dentition is the origin of the family's name, which is [[Greek language|Greek]] for "complete teeth".<ref name=":5" /><ref name=":1" />
The incisors are closely packed but do not develop a distinct straight chopping surface. They range from chisel-shaped in some entelodonts (''[[Archaeotherium]]'') to massive and rounded in others (''[[Daeodon]]'').<ref name=":3" /><ref name=":5" /> The canines have thick [[Tooth enamel|enamel]] and are circular in cross section, unlike most artiodactyls. In older individuals, the tip of the upper canine often heavily worn or even chipped off. Premolars are triangular when seen from the side, with a large and conical main [[Cusp (anatomy)|cusp]]. They are elongated from front-to-back and widely-spaced, taking up a large portion of the tooth row. The molar teeth are [[bunodont]], with very low and rounded cusps rather than shearing surfaces. Bunodont teeth are common in other omnivorous mammals, including pigs, bears, and humans. The upper molars have up to six cusps and a low crest (a precingulum) on the front edge of the crown.
=== Postcranial skeleton ===
Line 58:
=== Diet ===
[[File:Daeodon shoshonensis 2.png|thumb|Life restoration of ''Daeodon''|234x234px|left]]By comparison to pigs and peccaries, entelodonts were almost certainly [[Omnivore|omnivorous]] to an extent. Their teeth and jaw structure would have assisted processing of large and tough food items. Unlike the diverse and fully herbivorous [[Pecora|pecoran]] artiodactyls, entelodonts lack specializations for chopping and shredding grass and other particularly fibrous plants. Instead, entelodonts were probably [[Browsing (herbivory)|browsers]], with roots, nuts, fruits, and branches as their preferred sources of vegetation.<ref name=":3" /> A 2022 study found that ''[[Entelodon|Entelodon magnus]]'' had an omnivorous diet similar to [[wild boar]] (''Sus scrofa''). This conclusion was justified by its pattern of tooth [[microwear]], run through a [[linear discriminant analysis]] calibrated by modern herbivorous and omnivorous mammals. Based on pigs, entelodonts probably had a simple stomach and relied on the [[Cecum|caecum]] to ferment and digest plant matter. They would have been opportunistic omnivores, capable of digesting a variety of plant and animal matter and moderating their food preferences based on seasonal ability.<ref name=":6">{{Cite journal |
The same adaptations useful for processing tough plant material would be equally useful for carrion and bones, which could have been major components of the diet for some entelodonts.<ref name=":3" /> Unlike pigs, the youngest juvenile entelodonts had a full set of 32 [[deciduous teeth]]. The teeth were sharp, slender, and semi-serrated, less suitable for crushing tough food compared to adult entelodonts.<ref name=":5" />
Line 64:
In many entelodonts, the canine teeth acquire rounded wear surfaces at their tips, indicating regular use on hard material such as bones. Similar patterns of canine wear are observed in modern cats, which rely on strong bites administered through their canine teeth when killing prey. In some species the bases of the canines are scoured by smooth grooves, a trait consistent with abrasions from sediment-covered plant material such as roots.<ref name=":3" /> These grooves instead could have been produced by stripping long, fibrous vegetation, such as water-rich grape vines.<ref name=":5" /> ''Daeodon'' is known to have had a distinctive type of "piecrust" tooth wear at the tips of the premolars, with a flat [[Dentin|dentine]] surface surrounded by chipped [[Tooth enamel|enamel]]. This has also been observed in living [[Hyena|hyenas]].<ref name=":3" /> Few contemporary mammals approached entelodonts in the extent of adaptations consistent with scavenging. Fossils with large scrapes and puncture marks are found throughout entelodont-bearing sites in the American [[Great Plains]], including a skull of ''[[Merycoidodon]]'' with an embedded incisor of the entelodont ''Archaeotherium''.<ref name="BentonJr.2015">{{cite book|last1=Benton|first1=R. C.|url=https://books.google.com/books?id=ZcFtCQAAQBAJ|title=The White River Badlands: Geology and Paleontology|last2=Terry|first2=D. O.|last3=Evanoff|first3=E.|last4=McDonald|first4=H. G.|date=25 May 2015|publisher=Indiana University Press|isbn=978-0-253-01608-9}}</ref>
Entelodonts may have engaged in active predation, though the extent of this behavior is debated. Several species of modern pigs occasionally engage in predation, and even traditional herbivores like camels show dental wear consistent with scavenging.<ref name=":3" /> If they did engage in predation, entelodonts would not have been alone: many other contemporary mammals filled apex predator niches, including cat-like saber-toothed [[nimravidae|nimravids]], [[amphicyonidae|amphicyonid]]s ("bear-dogs"), and [[Hyaenodontidae|hyaenodontid]] [[creodonta|creodont]]s.<ref name="BentonJr.2015" /> One of the most apparent examples of circumstantial evidence for predation is a fossil found in the [[White River Formation]] of [[Wyoming]], representing a [[Cache (biology)|cache]] of partial skeletons and other remains of the early camelid ''[[Poebrotherium]]''. The carcasses were covered with large punctures on the skull, neck, and the transition from the [[Thoracic vertebrae|thoracic]] to [[Lumbar vertebrae|lumbar]] [[Vertebra|vertebrae]], which have been attributed to predation and scavenging by ''Archaeotherium''.<ref name="MPK">{{cite journal|author=Sundell, K. A.|year=1999|title=Taphonomy of a Multiple ''Poebrotherium'' kill site – an ''Archaeotherium'' meat cache|journal=Journal of Vertebrate Paleontology|volume=19|page=79A|doi=10.1080/02724634.1999.10011202|number=3}}</ref><ref>{{Cite web|last=Sundell|first=Kent A.|title=Taphonomy of a Multiple ''Poebrotherium'' kill site - an ''Archaeotherium'' meat cache|url=http://douglasfossils.com/multi-kill/
=== Intraspecific behavior ===
The jaw structure and estimated musculature hold numerous lines of evidence indicating that entelodonts could open their mouths unusually wide.<ref name=":3" /> This trait may have been useful in hunting or feeding on carrion, but similar adaptations have also been linked to competitive behaviors in herbivores. Hippos, a related group with similar adaptations, are aggressive herbivores which can open their jaws up to 150 degrees and display enlarged canines in order to intimidate rivals. Male hippos engage in head-to-head "yawning" and jaw-wrestling contests, while females attack by approaching from the side and slamming their head into the opponent's body.<ref>{{Cite web|url=http://library.sandiegozoo.org/factsheets/hippo/hippo.htm|title=Hippopotamus Fact Sheet|website=library.sandiegozoo.org|access-date=2018-10-28|archive-url=https://web.archive.org/web/20180720200538/http://library.sandiegozoo.org/factsheets/hippo/hippo.htm|archive-date=2018-07-20|url-status=dead}}</ref> The wide gape and low skulls of entelodonts would have assisted biting competitions, which are supported by fossil evidence. Large bite marks, including healed punctures, are common on skulls of various American entelodonts. These wounds are concentrated above the sinuses, and are only found on adult specimens. One could easily
==Classification==
Line 95:
* †''[[Daeodon]]''
* †''[[Entelodon]]''
* †''[[Entelodontellus]]''<ref>{{Cite journal |last1=Yu |first1=Yang |last2=Gao |first2=Hongyan |last3=Li |first3=Qiang |last4=Ni |first4=Xijun |date=2023 |title=A new entelodont (Artiodactyla, Mammalia) from the late Eocene of China and its phylogenetic implications |url=https://doi.org/10.1080/14772019.2023.2189436 |journal=Journal of Systematic Palaeontology |volume=21 |issue=1 |pages=2189436 |doi=10.1080/14772019.2023.2189436 |issn=1477-2019}}</ref>
* †''[[Eoentelodon]]''
* †''[[Paraentelodon]]''
* †''[[Proentelodon]]?''<ref name=":4" /> (may not be an entelodont)<ref>{{Cite journal|last1=Tsubamoto|first1=Takehisa|last2=Saneyoshi|first2=Mototaka|last3=Watabe|first3=Mahito|last4=Tsogtbaatar|first4=Khishigjav|last5=Mainbayar|first5=Buurei|date=2011|title=The Entelodontid Artiodactyl Fauna from the Eocene Ergilin Dzo Formation of Mongolia with Comments on Brachyhyops and the Khoer Dzan Locality|url=https://www.researchgate.net/publication/273893360|journal=Paleontological Research|volume=15|issue=4|pages=258–268|doi=10.2517/1342-8144-15.4.258|s2cid=129783561|issn=1342-8144}}</ref><ref>{{Cite journal|last1=Ducrocq|first1=Stéphane|last2=Chaimanee|first2=Yaowalak|last3=Jaeger|first3=Jean-Jacques|date=2019-03-01|title=First record of Entelodontidae (Mammalia, Artiodactyla) from the late Eocene of Southeast Asia
==In popular culture==
[[File:Knight entelodont.jpg|thumb|[[Charles R. Knight]]'s depiction of ''[[Entelodon]]'' (~1890s)|left|209x209px]]In popular media, entelodonts are sometimes nicknamed '''hell pigs''' or '''terminator pigs'''.<ref>[[Adrienne Mayor]] ''Fossil Legends of the First Americans''. [[Princeton University Press]], 2005. p. 213</ref>
Entelodonts appear in the third episode of the popular [[BBC]] documentary ''[[Walking with Beasts]]'', where, in the program, the narrator always refers to the creatures as "entelodonts" rather than a more specific genus, such as ''[[Entelodon]]''. The same creatures appear in another BBC production, the [[The Lost World (2001 film)|2001 remake]] of ''[[The Lost World (Arthur Conan Doyle)|The Lost World]]''.
Entelodonts were also the main focus of episode 4 of [[National Geographic Channel]]'s show ''[[Prehistoric Predators]]'' in an episode titled "Killer Pig". The episode featured a number of claims unproven or disproven by science, such as ''[[Archaeotherium]]'' (identified as "entelodont") being the top predator of the American [[Badlands]], and evolving directly into the even larger ''[[Daeodon]]'' (called "Dinohyus" in the episode).
==See also==
* [[Megafauna]]
* [[Sanitheriidae]]
==References==
Line 111 ⟶ 117:
==External links==
{{wikt | entelodont}}
* {{cite web|title=Museum display of Entelodont skeleton :: Geoscience Slides|url=http://digital.lib.uiowa.edu/u?/geoscience,34|website=[[University of Iowa]]|publisher=Entelodont Skeleton|access-date=2010-10-08|archive-date=2020-06-18|archive-url=https://web.archive.org/web/20200618160418/http://digital.lib.uiowa.edu/u?%2Fgeoscience%2C34|url-status=dead}}
{{Portal|Paleontology|Prehistoric mammals}}
{{Taxonbar|from=Q131139}}
[[Category:Entelodonts| ]]
[[Category:Burdigalian extinctions]]
[[Category:Eocene first appearances]]
[[Category:Taxa described in 1883]]
| |||