Daeodon

{{Short description|Extinct genus of mammals}} {{Automatic taxobox | fossil_range = Early Oligocene to Early Miocene (Arikareean–Early Hemingfordian) ~{{Fossil range|29|19}} {{period fossil range|Paleogene-Neogene|29|19}} | image = Daeodon_skull.jpg | image_upright = 1.15 | image_caption = A skull of ''D. shoshonensis'' at the Carnegie Museum of Natural History | taxon = Daeodon | authority = Cope, 1878 | type_species = {{extinct}}'''''Daeodon shoshonensis''''' | type_species_authority = Cope, 1878 | subdivision_ranks = Species | subdivision = *{{extinct}}'''''D. shoshonensis''''' Cope, 1878 *{{extinct}}'''''D. humerosum?''''' Cope, 1879 | synonyms = {{species list | Boochoerus|Cope, 1879 | Ammodon|Marsh, 1893 | Dinohyus|Peterson, 1905b}} }} thumb|''Daeodon shoshonensis'' life restoration [[File:Dinohyus hollandi (fossil mammal)Lower Miocene of Nebraska.jpg|thumb|''Daeodon (Dinohyus) hollandi,'' complete skeleton from the Agate Springs Fossil Quarry in Nebraska. See text for nomenclature history]]

'''''Daeodon''''' is an extinct genus of entelodont even-toed ungulates that inhabited North America about 29 to 19 million years ago from the early Oligocene to late early Miocene, making it one of the last known entelodonts.<ref name="lucasetal1997" /><ref name="Prothero&Foss207" /> The type species is ''Daeodon shoshonensis'', described from a very fragmentary holotype by Cope. Some authors synonymize it with ''Dinohyus hollandi'' and several other species (see below), but due to the lack of diagnostic material, this may be questionable.

Another large member of this family, possibly larger than ''Daeodon'', is the Asian ''Paraentelodon,'' but it is known by very incomplete material.<ref name=Prothero&Foss207>{{cite book|title=The Evolution of Artiodactyls|year=2007|publisher=JHU Press|url=https://books.google.com/books?id=qO8H_alEofAC|author=Donald R. Prothero|author2=Scott. E. Foss|isbn=9780801887352}}</ref><ref name=Gabunia> {{cite book | isbn = | url = https://books.google.com/books?id=MOEtAQAAIAAJ&q=Бенарская+фауна+олигоценовых+позвоночных | title = Бернарская фауна олигоценовых позвоночных (The Benarskaya Fauna of Oligocene Vertebrates) | publisher = Metsniereba, Tbilisi | date = 1964 | access-date = 2020-09-26 | quote = | pages = 109–133 | author = L. K. Gabunia }}</ref>

== Taxonomy == The genus ''Daeodon'' was erected by the American anatomist and paleontologist Edward Drinker Cope in 1878. He classified it as a perissodactyl and thought that it was closely related to ''Menodus''.<ref name=Cope1878>{{cite journal|last=Cope|first=E. D.|title=On some characters of the Miocene fauna of Oregon|journal=Paleontological Bulletin|year=1878|volume=30|pages=1–16}}</ref> This classification persisted until the description of ''"Elotherium" calkinsi'' in 1905,<ref name=Sinclair1905>{{cite journal|last=Sinclair|first=W. J.|authorlink=William John Sinclair|title=New and imperfectly known rodents and ungulates from the John Day Series|journal=Bull. Dept. Geology, Univ. California|year=1905|volume=4|pages=132–134}}</ref> a very similar and much more complete animal from the same rocks, which was promptly assigned as a species of ''Dynohyus'' by Peterson (1909).<ref name=Peterson1909/> This led to ''Daeodon''{{'}}s reclassification as a member of the family Entelodontidae. The exact relationships between ''Daeodon'' and other entelodonts are not well understood; some authors (Lucas et al., 1998) consider the greater morphological similarity of ''Daeodon'' to ''Paraentelodon'' rather than to earlier North American entelodonts, like ''Archaeotherium'', as evidence for ''Daeodon'' being a descendant from a Late Oligocene immigration of large Asian entelodonts to North America.<ref name=lucasetal1997/> However, the existence of distinct specimens of ''Archaeotherium'' showing characters reminiscent of those present in both ''Paraentelodon'' and ''Daeodon'' raises the possibility of both genera actually descending from a North American common ancestor.<ref name=Prothero&Foss207/><ref name=Foss&Fremd2001>{{cite journal|last=Foss|first=S. E.|author2=Fremd, T. J.|title=Biostratigraphy of the Entelodontidae (Mammalia: Artiodactyla) from the John Day Basin, Oregon|journal=PaleoBios|year=2001|volume=21|pages=53}}</ref> Although not specified in Cope's original description, the name ''Daeodon'' comes from the Greek words {{transliteration|grc|daios}}, meaning "hostile" or "dreadful" and {{transliteration|grc|odon}}, meaning "teeth".<ref>{{cite book |last1=Brown |first1=Roland W. | author-link=Roland W. Brown | title=Composition of Scientific Words : A manual of methods and a lexicon of materials for the practice of logotechnics |year=1977 |orig-year=1st Pub. 1954 |publisher=Smithsonian Institutional Press | location=Washington, D.C. | isbn=978-0-87474-286-2 | oclc=4495758 |via=Internet Archive |url=https://archive.org/details/compositionofsci00brow |access-date=27 August 2025}}</ref>

== Species == The type species of ''Daeodon'' is ''D. shoshonensis,'' which is based on a fragment of a lower jaw from the John Day Formation of Oregon. Several other species were assigned to the genus in the subsequent decades, like ''D. calkinsi'', ''D. mento''<ref name=Allen1926>{{cite journal|last=Allen|first=G. M.|title=Fossil mammals from South Carolina|journal=Bulletin of the Museum of Comparative Zoology|year=1926|volume=67|pages=447–467}}</ref> and ''D. minor''.<ref name=Loomis1932>{{cite journal|last=Loomis|first=F. B.|title=Two new Miocene entelodonts.|journal=Journal of Mammalogy|year=1932|volume=13|issue=4|pages=358–362|doi=10.2307/1374141|jstor=1374141}}</ref> Since 1945, it had been suggested that two other taxa were actually junior synonyms of ''Daeodon'',<ref name=Simpson1945>{{cite journal|last=Simpon|first=G. G.|title=The principles of classification and a classification of mammals.|journal=Bulletin of the American Museum of Natural History|year=1945|volume=85|pages=1–350}}</ref> but the formalization of this referral didn't take place until the work of Lucas et al. (1998).<ref name=lucasetal1997/> ''Ammodon leidyanum'', named by Cope's rival, O. C. Marsh, and ''Dinohyus hollandi,''<ref name=Peterson1905b>{{cite journal|last=Peterson|first=O. A.|title=A correction of the generic name (Dinochoerus) given to certain fossil remains from the Loup Fork Miocene of Nebraska|journal=Science|year=1905b|volume=22|issue=570|pages=719|doi=10.1126/science.22.570.719|pmid=17729479|url=https://zenodo.org/record/1447950|bibcode=1905Sci....22..719P}}</ref> a complete skeleton from the Agate Springs quarry of Nebraska,<ref name=Peterson1905a>{{cite journal|last=Peterson|first=O. A.|title=Preliminary note on a gigantic mammal from the Loup Fork Beds of Nebraska|journal=Science|year=1905a|volume=22|issue=555|pages=211–212|doi=10.1126/science.22.555.211|pmid=17835750|bibcode=1905Sci....22..211P|url=https://zenodo.org/record/1447942}}</ref> were found to be indistinguishable from each other and in turn both were indistinguishable from ''D. shoshonensis''.<ref name=lucasetal1997/> With the exception of ''D. calkinsi'', which was tentatively excluded from ''Daeodon'', the other previously recognized species of ''Daeodon'' were also synonymized to ''D. shoshonensis''.<ref name=lucasetal1997/> That same year, an obscure entelodont, ''Boochoerus humerosum'', was also synonymized to ''Daeodon'' by Foss and Fremd (1998) and, albeit its status as a distinct species was retained, they note that the differences could still be attributed to individual or population variation or sexual dimorphism.<ref name=Foss&Fremd1998>{{cite journal|last=Foss|first=S. E.|author2=Fremd, T.|title=A survey of the species of Entelodonts (Mammalia, Artiodactyla) of the John Day Basin, Oregon|journal=Dakoterra|year=1998|volume=5|pages=63–72}}</ref>

== Description == thumb|right|Skeletal restoration ''Daeodon shoshonensis'' is the largest-known entelodont;<ref name=lucasetal1997>{{cite journal | last1 = Lucas | first1 = S.G. | last2 = Emry | first2 = R.J. | last3 = Foss | first3 = S.E. | year = 1998 | title = Taxonomy and distribution of ''Daeodon'', an Oligocene-Miocene entelodont (Mammalia: Artiodactyla) from North America | url = https://www.biodiversitylibrary.org/part/48793 | journal = Proceedings of the Biological Society of Washington | volume = 111 | issue = 2| pages = 425–435 }}</ref> known adult individuals had skulls about {{Cvt|90|cm|ft|sigfig=1}} long and were about {{Cvt|1.77|m|ft}} tall at the shoulders, with large males estimated to have weighed at least {{Convert|750|kg|lb|abbr=on}}.<ref name="Joeckel-1990">{{Cite journal |last=Joeckel |first=R. M. |date=1990 |title=A Functional Interpretation of the Masticatory System and Paleoecology of Entelodonts |journal=Paleobiology |volume=16 |issue=4 |pages=459–482 |doi=10.1017/S0094837300010198 |jstor=2400970}}</ref><ref name=Peterson1909>{{cite journal|last=Peterson|first=O. A.|title=A revision of the Entelodontidae|journal=Memoirs of the Carnegie Museum|year=1909|volume=4|issue=3|pages=41–158|doi=10.5962/p.234831|url=https://www.biodiversitylibrary.org/bibliography/46733#/summary|hdl=2027/mdp.39015017493571|s2cid=247000277|hdl-access=free}}</ref> ''Daeodon'' is differentiated from other entelodonts by a suite of unique dental characters, the shape and relatively small size of the cheekbone flanges of its skull compared to those of ''Archaeotherium'', and the small size of its chin tubercle, as well as features of its carpus and tarsus and the fusion of the bones of the lower leg.<ref name=Prothero&Foss207/><ref name=Peterson1909/><ref name=Effinger1998/> Like other entelodonts, its limbs were long and slender with the bones of the foreleg fused together<ref name=lucasetal1997/><ref name=Effinger1998/> and with only two toes on each foot.<ref name=Peterson1909/><ref name=lucasetal1997/> It also had a relatively lightly constructed neck for the size of its head, whose weight was mostly supported by muscles and tendons attached to the tall spines of the thoracic vertebrae, similar to those of modern-day bison and white rhinoceros.<ref name=Effinger1998>{{cite book|last=Effinger|first=J. A.|title=Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals.|year=1998|publisher=Cambridge University Press|url=https://books.google.com/books?id=I-RgojcDyWYC|editor=Janis, C. M. |editor2=Scott, K. M. |editor3=Jacobs, L. L.|chapter=Entelodontidae|isbn=9780521355193}}</ref>

== Paleoecology ==

=== Habitat === ''Daeodon'' had a wide range in North America, with many fossils found in Agate Fossil Beds, representing an environment in a transition period between dense forests and expansive prairie, likely a major cause of their extinction in the early Miocene.<ref>[http://npshistory.com/publications/agfo/nrr-2009-080.pdf Agate Fossil Beds National Monument] National Park Service. 2009</ref> It adapted to the grassland with a more cursorial body plan than more basal entelodonts like ''Archaeotherium,'' losing their dewclaws entirely, proximally fused metacarpals, and similar shoulder musculature to bison.<ref name="Effinger1998" /><ref>{{cite thesis|author=Andrew Brant Clifford|title=Evolution and Mechanics of Unguligrady in Artiodactyls|url=https://repository.library.brown.edu/studio/item/bdr:191/PDF/ |location=Brown University|degree=PhD|date=May 2010}}</ref>

The Agate Springs bonebed was a floodplain environment with wet and dry seasons. ''Daeodon'' shared this landscape with small gazelle-like camels ''Stenomylus'', the large browsing chalicothere ''Moropus'', several species of predatory coyote- to wolf-sized amphicyonids that lived in packs, land beavers (''Palaeocastor'') that filled the ecological niche of modern prairie dogs, and thousands of small herd-living rhinoceros. The rhinos suffered massive periodic die-offs in the dry season, but ''Daeodon'' fossils are rare, which suggests they were neither social animals nor especially attracted to carrion.<ref>{{Cite web|title=Mammal Fossils - Agate Fossil Beds National Monument (U.S. National Park Service)|url=https://www.nps.gov/agfo/learn/nature/mammalfossils.htm|access-date=2018-10-28|website=www.nps.gov|language=en}}</ref>

===Diet=== ''Daeodon'' was omnivorous like all other entelodonts. Enamel patterns suggest eating of nuts, roots, and vines, as well as meat and bones. The superficial similarity to peccaries, hippos, and bears implies a wide range in terms of what plants ''Daeodon'' may have been eating. The dry seasons of North America at the time could get very harsh, so they may have supplemented their water intake by eating grape vines. The extent of its carnivory is debated, but tooth wear suggests they specialized in crushing bone and ripping meat, and bite marks on chalicothere bones suggest they either hunted or scavenged large herbivores. Foss (2001) argues its head was far too heavy to be effective in taking down large prey so it must have relied exclusively on scavenging, but its bison-like adaptations for running, the stereoscopic vision characteristic of predators, and evidence of predation in entelodonts calls this interpretation into question.<ref>{{Cite journal|date=1999|title=Abstract of Papers. Fifty-ninth Annual Meeting Society of Vertebrate Paleontology|url=https://www.jstor.org/stable/4524027|journal=Journal of Vertebrate Paleontology|volume=19|issue=3|pages=A1–A93|jstor=4524027|issn=0272-4634}}</ref> The uncertainty of their diets suggests they were likely opportunistic omnivores similar to bears, eating whatever they needed depending on the circumstance.<ref name=":0">Foss, S. E., 2001, Systematics and paleobiology of the Entelodontidae (Mammalia, Artiodactyla) [Ph.D. dissertation]: Dekalb, Northern Illinois University</ref>

===Behavior=== Entelodonts partook in intraspecific face biting, known from tooth marks on their skulls. Males would fight for dominance, possibly using their mandibular tubercles as protection in addition to their function as muscle attachments.<ref name=":0" /> Sexual dimorphism of the jugal protections exist in ''Archaeotherium,'' and with a smaller ''Daeodon'' sample size, such dimorphism can't be ruled out for ''Daeodon''. If dimorphic, the function of the expanded jugals was likely for display, supporting large preorbital glands similar to those forest hogs possessed for chemical communication.

== References == {{Portal|Paleontology|Prehistoric mammals}} {{Commons category|Daeodon}} {{Reflist}}

Category:Entelodonts Category:Miocene Artiodactyla Category:Miocene mammals of North America Category:Oligocene mammals of North America Category:Arikareean Category:Hemingfordian Category:White River Fauna Category:Burdigalian genus extinctions Category:Chattian genus first appearances Category:Fossil taxa described in 1878 Category:Taxa named by Edward Drinker Cope Category:Prehistoric Artiodactyla genera Category:Oligocene Artiodactyla