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'{{Automatic taxobox | fossil_range = [[Late Devonian]] ([[Frasnian]] to [[Famennian]]), {{Fossil range|382|358}} | image = Dunkleosteus (15677042802).jpg | image_caption = Reconstructed skull, [[Vienna Natural History Museum]] | image2 = D_Terrelli.png | image2_caption = Artist's reconstruction of ''D. terrelli'' | display_parents = 7 | taxon = Dunkleosteus | authority = [[Jean-Pierre Lehman|Lehman]], 1956 | type_species = †'''''Dunkleosteus terrelli''''' | type_species_authority = [[John Strong Newberry|Newberry]], 1873 | subdivision_ranks = [[Species]] | subdivision = {{collapsible list| ''D. terrelli'' <small>(Newberry, 1873 [originally ''[[Dinichthys]]''])</small><br /> ''D. ? belgicus'' <small>(Newberry) 1873</small><br /> ''D. denisoni'' <small>(Kulczycki) 1957</small><br /> ''D. marsaisi'' <small>Lehmann, 1956</small><br /> ''D. magnificus'' <small>(Hussakof & Bryant) 1919</small><br /> ''D. missouriensis'' <small>(Branson) 1914</small><br /> ''D. newberryi'' <small>(Clarke) 1885</small><br /> ''D. amblyodoratus'' <small>Carr & Hlavin, 2010</small><br /> ''D. raveri'' <small>Carr & Hlavin, 2010</small> }} }} '''''Dunkleosteus''''' is an [[extinct]] [[genus]] of large [[arthrodira|arthrodire]] fish that existed during the [[Late Devonian]] period, about 382–358 [[million years ago]]. It consists of ten species, some of which are among the largest [[placoderm]]s to have ever lived: ''D. terrelli'', ''D. belgicus'', ''D. denisoni'', ''D. marsaisi'', ''D. magnificus'', ''D. missouriensis'', ''D. newberryi'', ''D. amblyodoratus'', and ''D. raveri''. The largest and most well known species is ''D. terrelli'', which may have grown up to {{convert|6|-|10|m|ft|abbr=on}} long and weighed up to {{convert|1|-|4|MT|ST|abbr=on}}. However, it is likely that ''D. terrelli'' in real life was much smaller than previously assumed.<ref name=Engelman2022/> ''Dunkleosteus'' could quickly open and close its jaw, like modern-day [[Aquatic feeding mechanisms#Suction feeding|suction feeders]], and had a bite force of {{convert|4414|N|kg-f lb-f|0|abbr=on}} at the tip and {{convert|5363|N|kg-f lb-f|0|abbr=on}}<ref>{{Cite web |last=Anderson |first=Philip, S. L |last2=Westneat |first2=Mark, W. |date=January 2007 |title=Feeding mechanisms and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator. Biol |url=https://www.researchgate.net/publication/288518688_Feeding_mechanisms_and_bite_force_modelling_of_the_skull_of_Dunkleosteus_terrelli_an_ancient_apex_predator_Biol |url-status=live |website=Feeding mechanisms and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator. Biol}}</ref> at the blade edge. Numerous [[fossil]]s of the various species have been found in [[North America]], [[Poland]], [[Belgium]], and [[Morocco]]. ''Dunkleosteus'' was a [[pelagic fish]].<ref>https://www.researchgate.net/publication/235924093_The_Cleveland_Museum_of_Natural_History_PALEOECOLOGY_OF_DUNKLEOSTEUS_TERRELLI_PLACODERMI_ARTHRODIRA</ref> ==Etymology== ''Dunkleosteus'' was named in 1956 to honour [[David Dunkle]] (1911–1982), former curator of [[vertebrate paleontology]] at the [[Cleveland Museum of Natural History]]. The genus name ''Dunkleosteus'' combines [[David Dunkle]]'s surname with the Greek word {{wikt-lang|grc|ὀστέον}} ({{transliteration|grc|ostéon}} 'bone'), literally meaning 'Dunkle's-bone'. The [[type species]] ''D. terrelli'' was originally described in 1873 as a species of ''[[Dinichthys]]'', its specific epithet chosen in honor of Jay Terrell, the fossil's discoverer.<ref>"Dunkleosteus terrelli: Fierce prehistoric predator" page at ''Cleveland Museum of Natural History''. https://www.cmnh.org/dunk</ref> ==Taxonomy== Originally thought to be a member of the genus ''[[Dinichthys]]'', ''Dunkleosteus'' was later recognized as belonging to its own genus in 1956. It was thought to be closely related to ''Dinichthys'', and they were grouped together in the [[family (biology)|family]] [[Dinichthyidae]]. However, in the 2010 Carr & Hlavin [[phylogenetic]] study, ''Dunkleosteus'' and ''Dinichthys'' were found to belong to two separate [[clade]]s. Carr & Hlavin resurrected the family [[Dunkleosteidae]] and placed ''Dunkleosteus'', ''[[Eastmanosteus]]'', and a few other genera from Dinichthyidae within it.<ref name="Carr+2010">{{cite journal| author =Carr R. K., Hlavin V. J.| title =Two new species of Dunkleosteus Lehman, 1956, from the Ohio Shale Formation (USA, Famennian) and the Kettle Point Formation (Canada, Upper Devonian), and a cladistic analysis of the Eubrachythoraci (Placodermi, Arthrodira)| journal =Zoological Journal of the Linnean Society| volume =159| issue =1| pages =195–222| year =2010| doi =10.1111/j.1096-3642.2009.00578.x| doi-access =free}}</ref> Dinichthyidae, in turn, is left a [[Monotypic taxon|monospecific]] family.<ref name=Carr1995>{{cite journal|last=Carr|first=Robert K.|author2=William J. Hlavin|title=Dinichthyidae (Placodermi):A paleontological fiction?|journal=Geobios|date=September 2, 1995|volume=28|pages=85–87|doi=10.1016/S0016-6995(95)80092-1}}</ref> The [[cladogram]] below from the 2013 Zhu & Zhu study shows the placement of ''Dunkleosteus'' within [[Dunkleosteidae]] and ''[[Dinichthys]]'' within the separate clade [[Aspinothoracidi]]:<ref name=Zhu2013>{{Cite journal |author1=You-An Zhu |author2=Min Zhu |title=A redescription of Kiangyousteus yohii (Arthrodira: Eubrachythoraci) from the Middle Devonian of China, with remarks on the systematics of the Eubrachythoraci | journal=[[Zoological Journal of the Linnean Society]] |volume=169 |issue=4 |pages=798–819 |year=2013 |doi=10.1111/zoj12089 |doi-access=free }}</ref> {{clade| style=font-size:85%;line-height:85% |grouplabel1={{clade labels |width=10em; |label1='''Pachyosteomorphi''' |top1=65% |color1=green}} |label1='''[[Eubrachythoraci]]''' |1={{clade |1={{clade |label1='''[[Coccosteomorphi]]''' |1={{clade |1=''[[Coccosteus cuspidatus]]'' |2={{clade |1=''[[Harrytoombsia elegans]]'' |2={{clade |1=''[[Mcnamaraspis kaprios]]'' |label2=[[Incisoscutoidea]] |2={{clade |1=''[[Compagopiscis croucheri]]'' |2={{clade |1=''[[Incisoscutum ritchiei]]'' |2=''[[Incisoscutum sarahae]]'' }} |label3=[[Camuropiscidae]] |3={{clade |1=''[[Latocamurus coulthardi]]'' |2=''[[Camuropiscis laidlawi]]'' |3={{clade |1=''[[Rolfosteus canningensis]]'' |2=''[[Tubonasus lennardensis]]'' |3=''[[Fallacosteus turneri]]'' }} }} }} }} }} }} |label2='''[[Aspinothoracidi]]''' |2={{clade |1='''''[[Dinichthys herzeri]]''''' |barbegin1=green |2={{clade |1=''[[Hadrosteus rapax]]'' |bar1=green |2={{clade |1=''[[Gorgonichthys clarki]]'' |bar1=green |2={{clade |1=''[[Heintzichthys gouldii]]'' |bar1=green |label2=[[Selenosteidae]] |2={{clade |1=''[[Stenosteus angustopectus]]'' |bar1=green |2={{clade |1=''[[Gymnotrachelus hydei]]'' |bar1=green |2={{clade |1=''[[Rhinosteus parvulus]]'' |bar1=green |2=''[[Pachyosteus bulla]]'' |bar2=green }} }} }} }} }} }} }} }} |label2='''[[Dunkleosteoidea]]''' |2={{clade |1=''[[Westralichthys uwagedensis]]'' |bar1=green |2={{clade |1={{clade |1=''[[Protitanichthys rockportensis]]'' |bar1=green |label2=[[Panxiosteidae]] |2={{clade |1=''[[Panxiosteus ocullus]]'' |bar1=green |2=''[[Janiosteus timanicus]]'' |bar2=green |3=''[[Plourdosteus canadensis]]'' |bar3=green }} }} |label2='''[[Dunkleosteidae]]''' |2={{clade |1={{clade |1=''[[Eastmanosteus calliaspis]]'' |bar1=green |2=''[[Xiangshuiosteus wui]]'' |bar2=green }} |2={{clade |1=''[[Eastmanosteus pustulosus]]'' |bar1=green |2=''[[Kiangyousteus yohii]]'' |bar2=green |3=''[[Golshanichthys asiatica]]'' |bar3=green |4={{clade |1='''''Dunkleosteus amblyodoratus''''' |bar1=green |2='''''Dunkleosteus terrelli''''' |bar2=green |3='''''Dunkleosteus raveri''''' |barend3=green }} }} }} }} }} }} }} Alternatively, the subsequent 2016 Zhu ''et al.'' study using a larger [[morphology (biology)|morphological]] dataset recovered [[Panxiosteidae]] well outside of [[Dunkleosteoidea]], leaving the status of [[Dunkleosteidae]] as a clade grouping separate from Dunkleosteoidea in doubt, as shown in the cladogram below:<ref name=Zhu2016>{{Cite journal |last1=Zhu |first1=You-An |last2=Zhu |first2=Min |last3=Wang |first3=Jun-Qing |date=April 1, 2016 |title=Redescription of Yinostius major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the interrelationships of Brachythoraci |journal=[[Zoological Journal of the Linnean Society]] |volume=176 |issue=4 |pages=806–834 |doi=10.1111/zoj.12356|issn=0024-4082 |doi-access=free }}</ref> {{clade| style=font-size:85%;line-height:85% |label1='''[[Eubrachythoraci]]''' |1={{clade |label1='''[[Coccosteomorphi]]''' |1={{clade |label1=[[Coccosteoidea]] |1={{clade |label1=[[Coccosteidae]] |1={{clade |1={{clade |1=''[[Millerosteus minor]]'' |2=''[[Coccosteus cuspidatus]]'' }} |2={{clade |1=''[[Dickosteus threiplandi]]'' |2=''[[Watsonosteus fletti]]'' |3=''[[Protitanichthys rockportensis]]'' }} }} |label2='''[[Panxiosteidae]]''' |2={{clade |1=''[[Plourdosteus canadensis]]'' |2=''[[Panxiosteus ocullus]]'' |3=''[[Janiosteus timanicus]]'' }} }} |label2=[[Incisoscutoidea]] |2={{clade |1=''[[Harrytoombsia elegans]]'' |2={{clade |1=''[[Torosteus tuberculatus]]'' |2=''[[Torosteus pulchellus]]'' }} |3={{clade |1=''[[Mcnamaraspis kaprios]]'' |2={{clade |1=''[[Compagopiscis croucheri]]'' |2=''[[Trematosteus fontanellus]]'' |label3=[[Camuropiscidae]] |3={{clade |1={{clade |1=''[[Incisoscutum ritchiei]]'' |2=''[[Incisoscutum sarahae]]'' }} |2={{clade |1=''[[Rolfosteus canningensis]]'' |2={{clade |1=''[[Tubonasus lennardensis]]'' |2={{clade |1=''[[Fallacosteus turneri]]'' |2={{clade |1=''[[Camuropiscis laidlawi]]'' |2=''[[Latocamurus coulthardi]]'' }} }} }} }} }} }} }} }} }} |label2='''[[Pachyosteomorphi]]''' |2={{clade |1=''[[Rhachiosteus pterygiatus]]'' |2={{clade |label1='''[[Dunkleosteoidea]]''' |1={{clade |1=''[[Eastmanosteus calliaspis]]'' |2={{clade |1={{clade |1=''[[Eastmanosteus pustulosus]]'' |2=''[[Kiangyousteus yohii]]'' }} |2={{clade |1=''[[Golshanichthys asiatica]]'' |2={{clade |1=''[[Westralichthys uwagedensis]]'' |2={{clade |1={{clade |1='''''Dunkleosteus raveri''''' |2='''''Dunkleosteus terrelli''''' }} |2={{clade |1='''''Dunkleosteus amblyodoratus''''' |label2=[[Heterostiidae]] |2={{clade |1=''[[Heterosteus ingens]]'' |2=''[[Yinostius major]]'' }} }} }} }} }} }} }} |label2='''[[Aspinothoracidi]]''' |2={{clade |1=''[[Tapinosteus heintzi]]'' |2={{clade |1={{clade |1=''[[Bullerichthys fascidens]]'' |2={{clade |1=''[[Kendrickichthys cavernosus]]'' |2=''[[Bruntonichthys multidens]]'' }} }} |2={{clade |1='''''[[Dinichthys herzeri]]''''' |2={{clade |1=''[[Hadrosteus rapax]]'' |2={{clade |1=''[[Gorgonichthys clarki]]'' |label2=[[Selenosteidae]] |2={{clade |1=''[[Heintzichthys gouldii]]'' |2=''[[Pachyosteus bulla]]'' |3=''[[Gymnotrachelus hydei]]'' |4=''[[Stenosteus angustopectus]]'' |5=''[[Brachyosteus dietrichi]]'' |6={{clade |1=''[[Melanosteus occitanus]]'' |2=''[[Rhinosteus parvulus]]'' }} }} }} }} }} }} }} }} }} }} }} === Species === [[File:Dunkleosteus terrelli render 2022.png|thumb|Rendered reconstruction of ''Dunkleosteus terrelli'']] At least ten different species<ref name="Carr+2010"/><ref name=Denison>{{cite book|last=Denison|first=Robert|chapter=Placodermi|volume=2|title=Handbook of Paleoichthyology|year=1978|publisher=Gustav Fischer Verlag|location=Stuttgart New York|isbn=978-0-89574-027-4|pages=128}}</ref> of ''Dunkleosteus'' have been described so far. The [[type species]], ''D. terrelli'', is the largest, best-known species of the genus, measuring {{convert|6|-|10|m|ft|abbr=on}} in length. It has a rounded snout. ''D. terrelli''{{'s}} fossil remains are found in Upper Frasnian to Upper Famennian Late Devonian strata of the United States (Huron and [[Cleveland Shale]] of Ohio, the Conneaut of [[Pennsylvania]], [[Chattanooga Shale]] of Tennessee, [[Lost Burro Formation]], California, and possibly Ives [[breccia]] of Texas<ref name=Denison/>) and [[Europe]]. ''D. belgicus'' (?) is known from fragments described from the [[Famennian]] of [[Belgium]]. The median dorsal plate is characteristic of the genus, but, a plate that was described as a suborbital is anterolateral.<ref name=Denison/> ''D. denisoni'' is known from a small median dorsal plate, typical in appearance for ''Dunkleosteus'', but much smaller than normal. It is comparable in skull structure to ''D. marsaisi''.<ref name=Denison/> [[File:Dunkleosteus marsaisi 45.JPG|thumb|''D. marsaisi'' skull]] [[File:Dunkleosteus marsaisi life reconstruction.png|thumb|A rendered ''Dunkleosteus marsaisi'' head]] ''D. marsaisi'' refers to the ''Dunkleosteus'' fossils from the Lower Famennian Late Devonian strata of the [[Atlas Mountains]] in [[Morocco]]. It differs in size, the known skulls averaging a length of {{convert|35|cm|ft}} and in form to ''D. terrelli''. In ''D. marsaisi'', the snout is narrower, and a postpineal fenestra may be present. Many researchers and authorities consider it a synonym of ''D. terrelli''.<ref>{{cite journal|last=Murray|first=A.M.|title=The Palaeozoic, Mesozoic and Early Cenozoic fishes of Africa|journal=Fish and Fisheries|year=2000|volume=1|issue=2|pages=111–145|doi=10.1046/j.1467-2979.2000.00015.x}}</ref> H. Schultze regards ''D. marsaisi'' as a member of ''[[Eastmanosteus]]''.<ref name=Denison/><ref name=Schultz>{{cite journal|last=Schultz|first=H|title=Large Upper Devonian arthrodires from Iran|journal=Fieldiana Geology|year=1973|volume=23|pages=53–78|doi=10.5962/bhl.title.5270|doi-access=free}}</ref> ''D. magnificus'' is a large placoderm from the Frasnian [[Rhinestreet Shale]] of New York. It was originally described as ''[[Dinichthys]] magnificus'' by Hussakof and Bryant in 1919, then as "'' Dinichthys mirabilis''" by Heintz in 1932. Dunkle and Lane moved it to ''Dunkleosteus'' in 1971.<ref name=Denison/> ''D. missouriensis'' is known from fragments from Frasnian [[Missouri]]. Dunkle and Lane regard them as being very similar to ''D. terrelli''.<ref name=Denison/> ''D. newberryi'' is known primarily from a {{convert|28|cm|in}} long infragnathal with a prominent anterior cusp, found in the Frasnian portion of the [[Genesee Group]] of New York, and originally described as ''Dinichthys newberryi''.<ref name=Denison/> ''D. amblyodoratus'' is known from some fragmentary remains from Late Devonian strata of [[Kettle Point 44, Ontario|Kettle Point]], Canada. The species name means 'blunt spear' and refers to the way the [[nuchal]] and [[paranuchal]] plates in the back of the head form the shape of a blunted spearhead. Although it is known only from fragments, it is estimated to have been about {{convert|6|m|ft|1}} long in life.<ref name="Carr+2010"/> ''D. raveri'' is a small species, possibly 1 meter long, known from an uncrushed skull roof found in a carbonate concretion from near the bottom of the Huron Shale, of the Famennian [[Ohio Shale]] strata. Besides its small size, it had comparatively large eyes. Because ''D. raveri'' was found in the strata directly below the strata where the remains of ''D. terrelli'' are found, ''D. raveri'' may have given rise to ''D. terrelli''. The species name commemorates Clarence Raver of [[Wakeman, Ohio]], who discovered the concretion where the [[holotype]] was found.<ref name="Carr+2010"/> ==Description== [[File:Dunkleosteus2021.jpg|thumb|left|Restoration and size comparison of ''D. terrelli'']] The largest species, ''D. terrelli'', has been estimated to have grown up to {{convert|6|-|10|m|ft}} in length and weighed up to {{convert|1|-|4|MT|ST}},<!--no reliable source for weight among the sources listed--> making it one of the largest placoderms to have existed.<ref name=Anderson&Westneat2007/><ref name=Anderson&Westneat2009/><ref name="Ferron2017" /><ref>{{cite magazine|last=Williams|first=Nigel|year=2007|title=Force feeding|doi=10.1016/j.cub.2006.11.057}}</ref> However, in 2022, Engelman argued that large size estimates of {{convert|5|-|10|m|ft}} are 'unrealistic', since they are either largely speculative or based on comparison with much smaller relatives and body proportions of sharks. Based on the body proportions of arthodires, Engelman proposed an allometric method to accurately estimate the body size of ''Dunkleosteus'' which results in a maximum body length of {{convert|4|m|ft}} (no more than {{convert|5|m|ft}}) for the largest known specimen (CMNH 5936).<ref name="Engelman2022">{{cite book|last=Engelman|first=Russell|year=2022|chapter=A DEVONIAN FISH TALE: A NEW METHOD OF BODY LENGTH ESTIMATION IN PLACODERMS SUGGESTS MUCH SMALLER SIZES FOR THE FAMENNIAN ARTHRODIRE ''DUNKLEOSTEUS TERRELLI''|title=82nd Annual Meeting - SVP 2022 Program Guide|publisher=Society of Vertebrate Paleontology|page=136|url=https://vertpaleo.org/wp-content/uploads/2022/09/2022-SVP-Program-Abstract-Brochure_Preliminary.pdf}}</ref> A {{convert|4.6|m|ft}} long adult individual (also less than {{convert|5|m|ft}}) has been estimated to have weighed {{convert|665|kg|lb}}.<ref name="Carr2010">{{cite journal |last1=Carr |first1=Robert K. |title=Paleoecology of Dunkleosteus terrelli (Placodermi: Arthrodira). |journal=Kirtlandia |date=2010 |volume=57 |url= https://www.researchgate.net/publication/235924093}}</ref> Other species were much smaller, with some even attaining lengths of {{convert|25|cm|in}}.<ref name="Carr2010"/> ''Dunkleosteus'', together with most other placoderms, may have also been among the first [[vertebrate]]s to [[internal fertilization|internalize egg fertilization]], as seen in some modern sharks.<ref name=Ahlberg>{{cite journal |last1=Ahlberg |first1=Per |first2=Kate |last2=Trinajstic |first3=Zerina |last3=Johanson |first4=John |last4=Long |s2cid=205217467 |year=2009 |title=Pelvic claspers confirm chondrichthyan-like internal fertilization in arthrodires |journal=Nature |volume=460 |issue=7257 |pages=888–889 |doi=10.1038/nature08176|pmid=19597477 |bibcode=2009Natur.460..888A }}</ref> Some other placoderms have been found with evidence that they may have been [[viviparity|viviparous]], including what appears to have been an [[umbilical cord]]. [[File: Dunkleosteus skull steveoc.jpg|thumb|A skull diagram of ''Dunkleosteus'']] Mainly the armored frontal sections of specimens have been [[fossilized]], and consequently, the appearance of the other portions of the fish is mostly unknown.<ref>{{cite AV media|last=Dash|first=Sean|title=Prehistoric Monsters Revealed|location=United States|publisher=Workaholic Productions / History Channel|date=2008|url=https://www.youtube.com/watch?v=lEEhm4rzxEg|access-date=December 18, 2015}}{{cbignore}}{{Dead Youtube links|date=February 2022}}</ref> In fact, only about 5% of ''Dunkleosteus'' specimens have more than a quarter of their skeleton preserved.<ref>Carr, R, & G.L. Jackson. 2008. The Vertebrates fauna of the Cleveland member (Famennian) of the Ohio Shale. Society of Vertebrates Paleontology. 1–17.</ref> Because of this, many reconstructions of the hindquarters are often based on fossils of smaller [[arthrodire]]s, such as ''[[Coccosteus]]'', which have preserved hind sections. However, an exceptionally preserved specimen of ''D. terrelli'' preserves ceratotrichia in a pectoral fin, implying that the fin morphology of placoderms was much more variable than previously thought, and was heavily influenced by locomotory requirements. This knowledge, coupled with the knowledge that fish morphology is more heavily influenced by feeding niche than phylogeny, allowed a 2017 study to infer the body shape of ''D. terrelli''. This new reconstruction gives ''D. terrelli'' a much more shark-like profile, including a strong ventral lobe on its [[caudal fin]], the caudal fin having a high aspect ratio, narrow [[caudal peduncle]], and [[Fusiform|fusiform body]], given it was a big [[Pelagic fish|pelagic animal]], in contrast to reconstructions based on other placoderms.<ref name="Ferron2017">{{Cite journal|last1=Ferrón|first1=Humberto G.|last2=Martínez-Pérez|first2=Carlos|last3=Botella|first3=Héctor|date=December 6, 2017|title=Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data|journal=PeerJ|language=en|volume=5|pages=e4081|doi=10.7717/peerj.4081|pmid=29230354|pmc=5723140|issn=2167-8359}}</ref> The largest collection of ''Dunkleosteus'' fossils in the world is housed at the [[Cleveland Museum of Natural History]],<ref>{{cite web |url=https://www.cmnh.org/dunk |title=Dunkleosteus terrelli: Fierce prehistoric predator |author=<!--Not stated--> |website=Cleveland Museum of Natural History |access-date=July 21, 2022}}</ref> with smaller collections (in descending order of size) held at the [[American Museum of Natural History]],<ref>{{cite web |url=https://www.amnh.org/exhibitions/permanent/vertebrate-origins/dunkleosteus |title=Dunkleosteus |author=<!--Not stated--> |website=American Museum of Natural History |access-date=July 21, 2022}}</ref> [[Smithsonian National Museum of Natural History]],<ref name="Smithsonian" /> [[Yale Peabody Museum]],<ref>{{cite web |title=Collections Database of the Yale Peabody Museum |url=https://collections.peabody.yale.edu/search/Search/Results?sort=relevance&join=AND&lookfor0%5B%5D=dunkleosteus&type0%5B%5D=AllFields&lookfor0%5B%5D=&type0%5B%5D=AllFields&lookfor0%5B%5D=&type0%5B%5D=AllFields&bool0%5B%5D=AND&lookfor1%5B%5D=VP&type1%5B%5D=CatalogNumber&lookfor1%5B%5D=VPPU&type1%5B%5D=CatalogNumber&bool1%5B%5D=OR&filter%5B%5D=%7Ecollection%3A%22Vertebrate+Paleontology%22&limit=5&daterange%5B%5D=collecting_year_first&collecting_year_firstfrom=&collecting_year_firstto= |publisher=Yale Peabody Museum |access-date=12 August 2022}}</ref> the [[Natural History Museum in London]], and the [[Cincinnati Museum Center]]. Specimens of ''Dunkleosteus'' are on display in many museums throughout the world (see table below), most of which are casts of the same specimen: CMNH 5768, the largest well-preserved individual of ''D. terrelli'',<ref name="Ferron2017" />. The original CMNH 5768 is on display in the [[Cleveland Museum of Natural History]]. {| class="wikitable mw-collapsible mw-collapsed sortable" |+ Table of museums throughout the world that have ''Dunkleosteus'' specimens on display, highlighting the number of museums that display replicas of CMNH 5768 |- ! Museum !! City !! State/Province !! Country !! ''Dunkleosteus'' Specimen |- | [[Cleveland Museum of Natural History]] || [[Cleveland]] || [[Ohio]] || [[United States|U.S.]]|| CMNH 5768 (original), also has smaller juvenile individual on display (CMNH 7424). Two other mounted individuals currently off display (CMNH 6090 and CMNH 7054), and a fifth that was once mounted but has since been disassembled (CMNH 6194). |- | [[American Museum of Natural History]]|| [[New York City]] || [[New York (state)|New York]] || U.S.|| AMNH 7301 (at least in part, may be a composite)<ref>{{cite journal |last1=Dean |first1=Bashford |title=A Mounted Specimen of ''Dinichthys terrelli'' |journal=Memoirs of the American Museum of Natural History |date=1909 |volume=9 |issue=5 |pages=268–271 |hdl=2246/57 |url=https://digitallibrary.amnh.org/handle/2246/57}}</ref> |- | [[Smithsonian National Museum of Natural History]] || [[Washington D.C.]] || [[Washington D.C.]] || U.S. || USNM V 21314<ref name="Smithsonian">{{cite web |title=Collections Catalog of the Department of Paleobiology of the Smithsonian National Museum of Natural History |url=https://collections.nmnh.si.edu/search/paleo/ |publisher=Smithsonian Institute |access-date=12 August 2022}}</ref> |- | [[The Field Museum]] || [[Chicago]] || [[Illinois]] || U.S. || Cast of CMNH 5768 |- | [[Carnegie Museums of Pittsburgh|Carnegie Museum]] || [[Pittsburgh]] || [[Pennsylvania]] || U.S. || Cast of CMNH 5768 |- | [[University of Michigan Museum of Natural History]] || [[Ann Arbor]] || [[Michigan]] || U.S. || Cast of CMNH 5768 |- | [[Royal Ontario Museum]] || [[Toronto]] || [[Ontario]] || [[Canada]] || Cast of CMNH 5768 |- | [[Royal Tyrell Museum]] || [[Drumheller]] || [[Alberta]] || [[Canada]] || Cast of CMNH 5768 |- | [[University of Alberta Museum of Paleontology]]|| [[Edmonton]] || [[Alberta]] || [[Canada]] || Cast of CMNH 5768 |- | [[Denver Museum of Nature and Science]] || [[Denver]] || [[Colorado]] || U.S. || Cast of CMNH 5768 |- | [[Burpee Museum of Natural History]] || [[Rockford, Illinois|Rockford]] || [[Illinois]] || U.S. || Cast of CMNH 5768<ref>{{cite web |title="Photo of Burpee Museum Dunkleosteus"|url=https://commons.wikimedia.org/wiki/File:Burpee_-_Dunkleosteus_terrelli.JPG}}</ref> |- | [[Museum of Comparative Zoology]] || [[Harvard]] || [[Massachusetts]] || U.S. || Had a real mounted specimen of ''Dunkleosteus terrelli'' at one point, no longer clear if specimen is still on display.<ref>{{cite journal |last1=Stetson |first1=H. |title=Notes on the structure of Dinichthys and Macropetalichthys |journal=Bulletin of the Museum of Comparative Zoology |date=1930 |volume=71 |pages=19–39}}</ref> |- | [[Sam Noble Oklahoma Museum of Natural History]] || [[Oklahoma City]] || [[Oklahoma]] || U.S. || Cast of CMNH 5768 |- | [[BYU Museum of Paleontology]] || [[Provo, Utah|Provo]] || [[Utah]] || U.S. || Cast of CMNH 5768 |- | [[Denver Museum of Nature and Science]] || [[Denver]] || [[Colorado]] || U.S. || Cast of CMNH 5768 |- | [[South_Dakota_School_of_Mines_and_Technology#Campus|Museum of Geology, South Dakota School of Mines and Technology]] || [[Rapid City, South Dakota|Rapid City]] || [[South Dakota]] || U.S. || Cast of CMNH 5768 |- | [[Great Lakes Aquarium]] || [[Duluth]] || [[Minnesota]] || U.S. || Cast of CMNH 5768 |- | [[Indiana State Museum]] || [[Indianapolis]] || [[Indiana]] || U.S. || Cast of CMNH 5768 |- | [[Orton Geological Museum]] || [[Columbus, Ohio|Columbus]] || [[Ohio]] || U.S. || Cast of CMNH 5768<ref>{{cite web |title="Photo of Orton Geological Museum Dunkleosteus"|url=https://commons.wikimedia.org/wiki/File:Dunkleosteus_terrelli_(fossil_fish)_(Cleveland_Shale_Member,_Ohio_Shale,_Upper_Devonian;_Rocky_River_Valley,_Cleveland,_Ohio,_USA)_6_(33974377672).jpg}}</ref> |- | [[Cleveland Metroparks]], Rocky River Nature Center || [[Rocky River, Ohio|Rocky River]] || [[Ohio]] || U.S. || Cast of CMNH 5768 |- | [[Cincinnati Museum Center]] || [[Cincinnati]] || [[Ohio]] || U.S. || Cast of CMNH 5768 |- | [[Indiana State Museum]] || [[Indianapolis]] || [[Indiana]] || U.S. || Cast of CMNH 5768 |- | [[Pennsylvania State Museum]] || [[Harrisburg]] || [[Pennsylvania]] || U.S. || Cast of CMNH 5768<ref>{{cite web |url=https://statemuseumpa.org/dunkleosteus-websized/ |title=Dunkleosteus |author=<!--Not stated--> |date=September 1, 2017 |website=The State Museum of Pennsylvania |access-date=July 21, 2022}}</ref> |- | [[Muséum National d'Histoire Naturelle]] || [[Paris]] || [[Paris]] || [[France]] || Cast of CMNH 5768<ref>{{cite web |title="Photo of MNHN Dunkleosteus"|url=https://commons.wikimedia.org/wiki/File:Dunkleosteus_terrelli_343.JPG}}</ref> |- | [[Naturmuseum Senckenberg]] || [[Frankfurt]] || [[Hesse]] || [[Germany]] || Cast of CMNH 5768 |- | [[Vienna Natural History Museum]] || [[Vienna]] || Vienna || [[Austria]] || Cast of CMNH 5768<ref>{{cite web |title="Photo of Vienna Museum Dunkleosteus"|url=https://commons.wikimedia.org/wiki/File:Dunkleosteus_(15677042802).jpg}}</ref> |- | [[Swedish Museum of Natural History]] || [[Stockholm]] || [[Uppland]] || [[Sweden]] || Cast of CMNH 5768 |- | [[National Museum of Nature and Science, Tokyo|National Museum of Nature and Science]] || [[Tokyo]] || [[Kantō]] || [[Japan]] || Cast of CMNH 5768 |- | [[Queensland Museum]] || [[South Brisbane]] || [[Queensland]] || [[Australia]] || Cast of CMNH 5768<ref>{{cite web |url=https://commons.wikimedia.org/wiki/File:Dunkleosteus_skull_QM_email.jpg |title=File:Dunkleosteus skull QM email.jpg |author=<!--Not stated--> |date=August 21, 2006 |website=Wikimedia Commons |access-date=July 21, 2022}}</ref> |- | [[South Australian Museum]] || [[Adelaide]] || [[South Australia]] || [[Australia]] || Cast of CMNH 5768 |- | [[Buffalo Museum of Science]]|| [[Buffalo, New York|Buffalo]] || [[New York (state)|New York]] || U.S. || BMS E 2381 Specimen of "''Dinichthys''" ''magnificus'', which may or may not pertain to ''Dunkleosteus''. Additional isolated material of ''D. terrelli'' on display. |- | [[Wyoming Dinosaur Center]]|| [[Thermopolis, Wyoming|Thermopolis]] || [[Wyoming]] || U.S. || ''Dunkleosteus maraisai'', purportedly original specimen |- | [[Virginia Museum of Natural History]]|| [[Charleston, South Carolina|Charleston]] || [[South Carolina]] || U.S. || Cast of ''Dunkleosteus maraisai'' |- | [[Mace Brown Museum of Natural History]]|| [[Charleston, South Carolina|Charleston]] || [[South Carolina]] || U.S. || Cast of ''Dunkleosteus maraisai'' |- | [[Houston Museum of Natural Science]]|| [[Houston]] || [[South Texas]] || U.S. || Cast of ''Dunkleosteus maraisai'' || [[France]] || Cast of CMNH 5768<ref>{{cite web |title="Photo of MNHN Dunkleosteus"|url=https://commons.wikimedia.org/wiki/File:Dunkleosteus_terrelli_343.JPG}}</ref> |- | [[Naturmuseum Senckenberg]] || [[Frankfurt]] || [[Hesse]] || [[Germany]] || Cast of CMNH 5768 |- | [[Vienna Natural History Museum]] || [[Vienna]] || Vienna || [[Austria]] || Cast of CMNH 5768<ref>{{cite web |title="Photo of Vienna Museum Dunkleosteus"|url=https://commons.wikimedia.org/wiki/File:Dunkleosteus_(15677042802).jpg}}</ref> |- | [[Swedish Museum of Natural History]] || [[Stockholm]] || [[Uppland]] || [[Sweden]] || Cast of CMNH 5768 |- | [[National Museum of Nature and Science, Tokyo|National Museum of Nature and Science]] || [[Tokyo]] || [[Kantō]] || [[Japan]] || Cast of CMNH 5768 |- | [[Queensland Museum]] || [[South Brisbane]] || [[Queensland]] || [[Australia]] || Cast of CMNH 5768<ref>{{cite web |url=https://commons.wikimedia.org/wiki/File:Dunkleosteus_skull_QM_email.jpg |title=File:Dunkleosteus skull QM email.jpg |author=<!--Not stated--> |date=August 21, 2006 |website=Wikimedia Commons |access-date=July 21, 2022}}</ref> |- | [[South Australian Museum]] || [[Adelaide]] || [[South Australia]] || [[Australia]] || Cast of CMNH 5768 |- | [[Buffalo Museum of Science]]|| [[Buffalo, New York|Buffalo]] || [[New York (state)|New York]] || U.S. || BMS E 2381 Specimen of "''Dinichthys''" ''magnificus'', which may or may not pertain to ''Dunkleosteus''. Additional isolated material of ''D. terrelli'' on display. |- | [[Wyoming Dinosaur Center]]|| [[Thermopolis, Wyoming|Thermopolis]] || [[Wyoming]] || U.S. || ''Dunkleosteus maraisai'', purportedly original specimen |- | [[Virginia Museum of Natural History]]|| [[Charleston, South Carolina|Charleston]] || [[South Carolina]] || U.S. || Cast of ''Dunkleosteus maraisai'' |- | [[Mace Brown Museum of Natural History]]|| [[Charleston, South Carolina|Charleston]] || [[South Carolina]] || U.S. || Cast of ''Dunkleosteus maraisai'' |- | [[Houston Museum of Natural Science]]|| [[Houston]] || [[South Texas]] || U.S. || Cast of ''Dunkleosteus maraisai'' |} ===Diet=== ''Dunkleosteus terrelli'' possessed a [[four-bar linkage]] mechanism for [[Fish jaw|jaw]] opening that incorporated connections between the skull, the thoracic shield, the lower jaw and the jaw muscles joined together by movable joints.<ref name=Anderson&Westneat2009>{{cite journal |last=Anderson |first=P.S.L. |author2=Westneat, M. |title=A biomechanical model of feeding kinematics for ''Dunkleosteus terrelli'' (Arthrodira, Placodermi) |journal=Paleobiology |date=2009 |volume=35 |issue=2 |pages=251–269 |doi=10.1666/08011.1 |s2cid=86203770 |url=http://projects.fieldmuseum.org/sites/default/files/DunkPaleoBio.pdf |access-date=October 29, 2017 |archive-date=November 7, 2017 |archive-url=https://web.archive.org/web/20171107014026/http://projects.fieldmuseum.org/sites/default/files/DunkPaleoBio.pdf |url-status=dead }}</ref><ref name=Anderson&Westneat2007>{{Cite journal |last=Anderson |first=P.S.L. |author2=Westneat, M. |title=Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator |journal=Biology Letters |volume=3 |issue=1 |pages=76–79 |date=2007 |doi=10.1098/rsbl.2006.0569 |pmid=17443970 |pmc=2373817}}</ref> This mechanism allowed ''D. terrelli'' to both achieve a high speed of jaw opening, opening their jaws in 20 milliseconds and completing the whole process in 50–60 milliseconds (comparable to modern fishes that use [[Aquatic feeding mechanisms#Suction feeding|suction feeding]] to assist in prey capture;<ref name=Anderson&Westneat2007/>) and producing high bite forces when closing the jaw, estimated at {{cvt|6000|N|kg-f lb-f|0}} at the tip and {{cvt|7400|N|kg-f lb-f|0}} at the blade edge in the largest individuals.<ref name=Anderson&Westneat2009/> The pressures generated in those regions were high enough to puncture or cut through [[cuticle]] or [[dermal bone|dermal]] armor,<ref name=Anderson&Westneat2007/> suggesting that ''D. terrelli'' was adapted to prey on free-swimming, armored prey such as [[ammonite]]s and other placoderms.<ref name=Anderson&Westneat2009/> In addition, teeth of a [[Chondrichthyes|chondrichthyan]] thought to belong to ''[[Orodus]]'' (''Orodus'' spp.) were found in association with ''Dunkleosteus'' remains, suggesting that these were probably stomach contents regurgitated from the animal. ''Orodus'' is thought to be tachypelagic, or a fast-swimming [[pelagic fish]]. Thus, ''Dunkleosteus'' might have been fast enough to catch these fast organisms, and not a slow swimmer like originally thought.<ref name="Ferron2017" /> Fossils of ''Dunkleosteus'' are frequently found with [[Bolus (digestion)|bolus]]es of fish bones, semidigested and partially eaten remains of other fish.<ref name="Virtual Fossil">{{cite web|url= http://www.fossilmuseum.net/Fossil_Galleries/Fish_Devonian/Dunkleosteous/Dunkleosteus.htm |title=Dunkleosteus Placodermi Devonian Armored Fish from Morocco |work=Fossil Archives |publisher=The Virtual Fossil Museum |access-date=April 26, 2009}}</ref> As a result, the [[fossil]] record indicates it may have routinely regurgitated prey bones rather than digest them. Mature individuals probably inhabited deep sea locations, like other Placoderms, living in shallow waters during adolescence.<ref>{{Cite web|url=http://bioweb.uwlax.edu/bio203/f2013/peters_sadi/habitat.htm|title=UWL Website}}</ref> ===Juveniles=== [[File:Dunkleosteus juvenile fossil - Cleveland Museum of Natural History (34421618320).jpg|thumb|Juvenile specimen CMNH 7424]] [[morphology (biology)|Morphological]] studies on the lower jaws of juveniles of ''D. terrelli'' reveal they were proportionally as robust as those of adults, indicating they already could produce high bite forces and likely were able to shear into resistant prey tissue similar to adults, albeit on a smaller scale. This pattern is in direct contrast to the condition common in [[tetrapod]]s in which the jaws of juveniles are more [[gracile]] than in adults.<ref name="Snively_etal_2009">{{cite journal |last=Snively |first=E. |author2=Anderson, P.S.L. |author3=Ryan, M.J. |date=2009 |title=Functional and ontogenetic implications of bite stress in arthrodire placoderms |url=https://www.biodiversitylibrary.org/page/51811342#page/60/mode/1up |journal=Kirtlandia |volume=57}}</ref> ==See also== * [[List of placoderms]] ==References== {{notes}} {{reflist}} ==Further reading== * {{cite journal|first=Philip S. L.|last=Anderson|s2cid=86583150|year=2008|title=Shape Variation Between Arthrodire Morphotypes Indicates Possible Feeding Niches|journal=Journal of Vertebrate Paleontology|volume=28|number=4|pages=961–969|doi=10.1671/0272-4634-28.4.961}} ==External links== {{Commons category|Dunkleosteus}} {{Wikispecies|Dunkleosteus}} * [http://www.ucmp.berkeley.edu/vertebrates/basalfish/placodermi.html ''Introduction to the Placodermi: Extinct Armored Fishes with Jaws''. Waggoner, Ben (2000). Retrieved Aug 1, 2005] * [http://www.nbcnews.com/id/15940709 MSNBC: Prehistoric fish packed a mean bite] * [http://news.bbc.co.uk/1/hi/sci/tech/6195188.stm BBC: Ancient 'Jaws' had monster bite] {{Arthrodira|E.}} {{Taxonbar|from=Q131039|from2=Q911597|from3=Q911599|from4=Q911605|from5=Q911606|from6=Q911611|from7=Q911612|from8=Q911616|from9=Q911618|from10=Q911593|from11=Q25357547}} [[Category:Dunkleosteidae]] [[Category:Apex predators]] [[Category:Placoderms of Africa]] [[Category:Fossils of Morocco]] [[Category:Placoderms of Europe]] [[Category:Fossils of Belgium]] [[Category:Placoderms of North America]] [[Category:Fossils of Canada]] [[Category:Paleontology in Missouri]] [[Category:Paleontology in Pennsylvania]] [[Category:Paleontology in Tennessee]] [[Category:Late Devonian first appearances]] [[Category:Late Devonian animals]] [[Category:Famennian extinctions]] [[Category:Fossil taxa described in 1956]] [[Category:Taxa named by John Strong Newberry]]'