Biology:Dunkleosteus

From HandWiki
Short description: Genus of extinct fishes

Dunkleosteus
Temporal range: Late Devonian (Frasnian to Famennian), 382–358 Ma
Dunkleosteus terrelli (fossil fish) (Cleveland Shale Member, Ohio Shale, Upper Devonian; Rocky River Valley, Cleveland, Ohio, USA) 21 (34001200911).jpg
Partially reconstructed D. terrelli skull (specimen CMNH 5768), Cleveland Museum of Natural History
Scientific classification e
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Placodermi
Order: Arthrodira
Suborder: Brachythoraci
Family: Dunkleosteidae
Genus: Dunkleosteus
Lehman, 1956
Type species
Dinichthys terrelli
Newberry, 1873
Species

Dunkleosteus is an extinct genus of large arthrodire ("jointed-neck") fish that existed during the Late Devonian period, about 382–358 million years ago. It was a pelagic fish inhabiting open waters, and one of the first apex predators of any ecosystem.[1]

Dunkleosteus consists of ten species, some of which are among the largest placoderms ("plate-skinned") to have ever lived: D. terrelli, D. belgicus, D. denisoni, D. marsaisi, D. magnificus, D. missouriensis, D. newberryi, D. amblyodoratus, D. raveri, and D. tuderensis. The largest and most well known species is D. terrelli. Since body shape is not known, various methods of estimation put the living total length of the largest known specimen between 4.1 to 10 m (13 to 33 ft) long and weigh around 1–4 t (1.1–4.4 short tons).[2] However, lengths of 5 metres (16 ft) or more are not well supported by evidence and the most extensive analyses on the size of Dunkleosteus support smaller length estimates.[2][3]

Dunkleosteus could quickly open and close its jaw, creating suction like modern-day suction feeders, and had a bite force that is considered the highest of any living or fossil fish, and among the highest of any animal. Numerous fossils of the various species have been found in North America, Poland , Belgium, and Morocco.

Discovery

Dunkleosteus fossils were first discovered in 1867 by Jay Terrell, a hotel owner and amateur paleontologist who collected fossils in the cliffs along Lake Erie near his home of Sheffield Lake, Ohio (due west of Cleveland), United States. Terrell donated his fossils to John Strong Newberry and the Ohio Geological Survey, who in 1873 described all the material as belonging to a single new genus and species: Dinichthys herzeri. However, with later fossil discoveries, by 1875 it became apparent multiple large fish species were present in the Ohio Shale. Dinichthys herzeri came from the lowermost layer, the Huron Shale, whereas most of the fossils were coming from the younger Cleveland Shale and represented a distinct species.[4] Newberry named this more common species "Dinichthys" terrelli, after Terrell.[5] Most of Terrell's original collection does not survive, having been destroyed by a fire in Elyria, Ohio, in 1873.[4][6]

The largest collection of Dunkleosteus fossils in the world is housed at the Cleveland Museum of Natural History,[7] with smaller collections (in descending order of size) held at the American Museum of Natural History,[8] Smithsonian National Museum of Natural History,[9] Yale Peabody Museum,[10] 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.[2][11] The original CMNH 5768 is on display in the Cleveland Museum of Natural History.

Taxonomy

Dunkleosteus was named by Jean-Pierre Lehman in 1956 to honour David Dunkle (1911–1984), 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 ὀστέον (ostéon 'bone'), literally meaning "Dunkle's bone".[12]

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 Dinichthyidae. However, in the phylogenetic analysis of Carr and Hlavin (2010), Dunkleosteus and Dinichthys were found to belong to separate clades of arthrodires: Dunkleosteus belonged to a group called the Dunkleosteoidea while Dinichthys belonged to the distantly related Aspinothoracidi. Carr & Hlavin resurrected the family Dunkleosteidae and placed Dunkleosteus, Eastmanosteus, and a few other genera from Dinichthyidae within it.[13] Dinichthyidae, in turn, is left a monospecific family, though closely related to arthrodires like Gorgonichthys and Heintzichthys.[14]

Front view of D. terrelli skull

The cladogram below from the study of Zhu & Zhu (2013) shows the placement of Dunkleosteus within Dunkleosteidae and Dinichthys within the separate clade Aspinothoracidi:[15] Lua error: Internal error: The interpreter exited with status 1.

Alternatively, the subsequent 2016 Zhu et al. study using a larger 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:[16] Lua error: Internal error: The interpreter exited with status 1.

Species

At least ten different species[13][17] of Dunkleosteus have been described so far. However, many of them are poorly characterized and may be synonyms of previously named species or not pertain to Dunkleosteus.[18] Dunkleosteus as currently defined is a wastebasket taxon for large dunkleosteoid arthrodires that are more evolutionarily derived than Eastmanosteus.[18]

Labelled skull diagram of D. terrelli

The type species, D. terrelli, is the largest, best-known species of the genus. Size estimates for this species range from Lua error: Internal error: The interpreter exited with status 1. in length, though estimates greater than 4.5 m are poorly supported.[3][2] Skulls of this species can be up to Lua error: Internal error: The interpreter exited with status 1. in length.[2] D. terrelli's fossil remains are found in Upper Frasnian to Upper Famennian Late Devonian strata of the United States (Huron, Chagrin, and Cleveland Shales of Ohio, the Conneaut and Chadakoin Formations of Pennsylvania, the Chattanooga Shale of Tennessee, the Lost Burro Formation of California, and possibly the Ives breccia of Texas[17]) 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 an anterolateral.[17] Lelièvre (1982) considers this taxon a nomen dubium ("doubtful name") and suggests the material may actually pertain to Ardennosteus.[19]

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.[17]

D. marsaisi skull

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 Lua error: Internal error: The interpreter exited with status 1. 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.[20] H. Schultze regards D. marsaisi as a member of Eastmanosteus.[17][21]

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 (1971) moved it to Dunkleosteus,[17] whereas Dennis-Bryan (1987) considered it to belong to the genus Eastmanosteus[22] This species has a skull length of Lua error: Internal error: The interpreter exited with status 1. and a total estimated length of approximately Lua error: Internal error: The interpreter exited with status 1..[18]

D. missouriensis is known from fragments from Frasnian Missouri. Dunkle and Lane regard them as being very similar to D. terrelli.[17]

D. newberryi is known primarily from a Lua error: Internal error: The interpreter exited with status 1. 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.[17] Lebedev et al. (2023) noted D. newberryi has an unusually long marginal tooth row compared to other species of Dunkleosteus and lacks the accessory odontoids typical of this genus, suggesting it might not belong to Dunkleosteus or even Dunkleosteoidea[18]

D. amblyodoratus is known from some fragmentary remains from Late Devonian strata of Kettle Point Formation, Ontario. 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.[13]

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 containing the holotype.[13]

D. tuderensis is known from an infragnathal found in the lower-middle Famennian-aged Bilovo Formation of the Tver Region in northwest Russia. The specific name refers to the Maliy Tuder River as the holotype was found on its bank.[18]

In total, of the ten or so species listed above only four are agreed upon as valid species of Dunkleosteus by all researchers: D. terrelli (which may or may not include Dunkleosteus material from Morocco), D. raveri, D. tuderensis, and possibly D. amblyodoratus (which is known from limited material that appears distinct but is difficult to compare with other dunkleosteids). The taxonomy of early late Devonian (Frasnian) species is poorly established, whereas latest Devonian (Famennian) species are easily referable to this genus. This is not counting additional material assigned to Dunkleosteus sp. from the Famennian of California, Texas, Tennessee, and Poland.[18][23]

Description

Size and anatomy

Comparison of multiple size estimates for D. terrelli

Mainly the armored frontal sections of specimens have been fossilized, and consequently, the appearance of the other portions of the fish is mostly unknown.[24] In fact, only about 5% of Dunkleosteus specimens have more than a quarter of their skeleton preserved.[25] Because of this, many reconstructions of the hindquarters are often based on fossils of smaller arthrodires, such as Coccosteus, which have preserved hind sections,[2] leading to widely varying size estimates.[2]

Dunkleosteus is one of the largest known placoderms, with its maximum size being variably estimated as anywhere from Lua error: Internal error: The interpreter exited with status 1. by different researchers.[26][27][11][28][2] However, most cited length estimates are speculative and lack quantitative or statistical backing, and lengths of Lua error: Internal error: The interpreter exited with status 1. or more are poorly supported.[11][2] Most studies that estimate the length of Dunkleosteus do not provide information as to how these estimates were calculated, the measurements used to scale them, or which specimens were examined. Most are implied to be based on either CMNH 5768 (the largest complete armor of Dunkleosteus) or CMNH 5936 (the largest known jaw fragment). Lua error: Internal error: The interpreter exited with status 1.Most of the studies with well-defined methods produce lengths of Lua error: Internal error: The interpreter exited with status 1. or less for Dunkleosteus terrelli,[2] with the exception of Ferrón et al. (2017), which produces larger estimates of Lua error: Internal error: The interpreter exited with status 1. based on upper jaw perimeter of modern sharks.[11] However, arthrodires have proportionally larger mouths than modern sharks, making the lengths estimated by Ferrón et al. (2017) unreliable.[3] Upper jaw perimeter overestimates the size of complete arthrodires like Coccosteus and the estimates of Ferrón et al. (2017) result in Dunkleosteus having an extremely small head and hyper-elongate trunk relative to the known dimensions of the fossils.[3] If the reconstruction presented in Ferrón et al. (2017) is scaled to the known dimensions of CMNH 5768, it produces a length of Lua error: Internal error: The interpreter exited with status 1..[3]

Carr (2010) estimated a Lua error: Internal error: The interpreter exited with status 1. long adult individual of Dunkleosteus terrelli to have weighed Lua error: Internal error: The interpreter exited with status 1., assuming a shark-like body plan and a similar length-weight relationship.[29] Engelman (2023), using an ellipsoid volumetric method, estimated weights of Lua error: Internal error: The interpreter exited with status 1. for typical (Lua error: Internal error: The interpreter exited with status 1. long) adult Dunkleosteus, and weights of Lua error: Internal error: The interpreter exited with status 1. for the largest (Lua error: Internal error: The interpreter exited with status 1. in this study) individual.[2] The higher weights by Engelman (2023) are mostly a result of the fact that arthrodires tend to have relatively deeper and wider bodies compared to sharks.[2]

An exceptionally preserved specimen of D. terrelli preserves a pectoral fin outline with ceratotrichia, 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 caudal fin shape of D. terrelli, reconstructing this fin with a strong ventral lobe, a high aspect ratio, narrow caudal peduncle, in contrast to previous reconstructions based on the anguilliform caudal fin of coccosteomorph placoderms.[11]

Length estimations of D. terrelli

Length estimates of Dunkleosteus terrelli (modified from Table 7 of Engelman 2023[2])
Study (author) Year Length Method Reference
Newberry 1875 Lua error: Internal error: The interpreter exited with status 1. Extrapolated from Coccosteus cuspidatus, measurements and specimen used unclear [4]
Newberry 1889 Lua error: Internal error: The interpreter exited with status 1. Unstated (implied extrapolation from Coccosteus) [30]
Dean 1895 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens unstated [31]
Hussakof 1905 Lua error: Internal error: The interpreter exited with status 1. (AMNH FF 195)
Lua error: Internal error: The interpreter exited with status 1. (extrapolated to CMNH 5768 by Engelman 2023[2] assuming similar head-trunk proportions)
Entering angle of body [32]
Anonymous 1923 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [33]
Hyde 1926 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [34]
Romer 1966 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [35]
Colbert 1969 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [36]
Denison 1978 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [17]
Williams 1992 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [37]
Janvier 2003 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [38]
Young 2003 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [39]
Anderson and Westneat 2007 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [26]
Anderson and Westneat 2009 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [27]
Carr 2010 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [29]
Long 2010 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [40]
Sallan and Galimberti 2015 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [41]
Ferrón et al. 2017 Lua error: Internal error: The interpreter exited with status 1. (average adult, CMNH 5768)
Lua error: Internal error: The interpreter exited with status 1. (largest individual, CMNH 5936)
Upper jaw perimeter [11]
Long et al. 2019 Lua error: Internal error: The interpreter exited with status 1. Methods, measurements, and specimens used not stated [42]
Johanson et al. 2019 Lua error: Internal error: The interpreter exited with status 1. (CMNH 50322)
Lua error: Internal error: The interpreter exited with status 1. (extrapolated to CMNH 5768 by Engelman 2023 assuming similar head-trunk proportions)
Methods and measurements not stated [43]
Engelman 2023 Lua error: Internal error: The interpreter exited with status 1. (average adult, CMNH 5768)
Lua error: Internal error: The interpreter exited with status 1. (largest individual, CMNH 5936)
Orbit-opercular length (head length minus snout) [2]
Engelman 2023 Lua error: Internal error: The interpreter exited with status 1. (average adult, CMNH 5768) Skull length in Coccosteus [2]
Engelman 2023 Lua error: Internal error: The interpreter exited with status 1. (average adult, CMNH 5768) Infragnathal length in Coccosteus (source considers this estimate unreliable due to Dunkleosteus having a relatively larger mouth than Coccosteus) [2]
Engelman 2023 Lua error: Internal error: The interpreter exited with status 1. (average adult, CMNH 5768) Entering angle of body [2]
Engelman 2023 Lua error: Internal error: The interpreter exited with status 1. (average adult, CMNH 5768) Length of posteroventrolateral plate [2]
Engelman 2023 Lua error: Internal error: The interpreter exited with status 1. (average adult, CMNH 5768) Inferred location of pelvic girdle [2]

Paleobiology

Diet

Partial lower jaw of CMNH 5936, the largest known individual of Dunkleosteus terrelli. Scale = 10 cm.

Dunkleosteus terrelli possessed a four-bar linkage mechanism for jaw opening that incorporated connections between the skull, the thoracic shield, the lower jaw and the jaw muscles joined by movable joints.[27][26] 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 suction feeding to assist in prey capture[26]) and producing high bite forces when closing the jaw, estimated at Lua error: Internal error: The interpreter exited with status 1. at the tip and Lua error: Internal error: The interpreter exited with status 1. at the blade edge,[26] or even up to Lua error: Internal error: The interpreter exited with status 1. and Lua error: Internal error: The interpreter exited with status 1. respectively.[27] The bite force is considered the highest of any living or fossil fish, and among the highest of any animal.[26] The pressures generated in those regions were high enough to puncture or cut through cuticle or dermal armor,[26] suggesting that D. terrelli was adapted to prey on free-swimming, armored prey such as ammonites and other placoderms.[27]

In addition, teeth of a 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.[11] Fossils of Dunkleosteus are frequently found with boluses of fish bones, semidigested and partially eaten remains of other fish.[44] 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.[45]

A specimen of Dunkleosteus (CMNH 5302), and Titanichthys (CMNH 9889), show damage said to be puncture damage from the bony fangs of other Dunkleosteus.[27]

Reproduction

Dunkleosteus, together with most other placoderms, may have also been among the first vertebrates to internalize egg fertilization, as seen in some modern sharks.[46] Some other placoderms have been found with evidence that they may have been viviparous, including what appears to have been an umbilical cord.[47]

Growth

Lua error: Internal error: The interpreter exited with status 1. 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 tetrapods in which the jaws of juveniles are more gracile than in adults.[48]

See also

  • List of placoderms

References

Lua error: Internal error: The interpreter exited with status 1.

  1. Tamisiea, Jack (4 March 2023). "Dunk Was Chunky, but Still Deadly" (in en). New York Times. https://www.nytimes.com/2023/03/04/science/chunky-dunk-fossil.html. 
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 Engelman, Russell K. (2023). "A Devonian Fish Tale: A New Method of Body Length Estimation Suggests Much Smaller Sizes for Dunkleosteus terrelli (Placodermi: Arthrodira)" (in en). Diversity 15 (3): 318. doi:10.3390/d15030318. ISSN 1424-2818. 
  3. 3.0 3.1 3.2 3.3 3.4 Engelman, Russell (10 April 2023). "Giant, swimming mouths: oral dimensions of extant sharks do not accurately predict body size in Dunkleosteus terrelli (Placodermi: Arthrodira)" (in en). PeerJ 11: e15131. doi:10.7717/peerj.15131. PMID 37065696. 
  4. 4.0 4.1 4.2 Newberry, John S. (1875). "Descriptions of fossil fishes". Report of the Geological Survey of Ohio. Volume II. Geology and Paleontology. 2. Columbus: Nevins and Myers, State Printers. p. 24. https://www.biodiversitylibrary.org/item/116994#page/15/mode/1up. 
  5. "Dunkleosteus terrelli: Fierce prehistoric predator" page at Cleveland Museum of Natural History. https://www.cmnh.org/dunk
  6. Claypole, E. W. (1893). "The three great fossil placoderms of Ohio". American Geologist 12: 89–99. https://www.biodiversitylibrary.org/item/240810#page/107/mode/1up. 
  7. "Dunkleosteus terrelli: Fierce prehistoric predator". https://www.cmnh.org/dunk. 
  8. "Dunkleosteus". https://www.amnh.org/exhibitions/permanent/vertebrate-origins/dunkleosteus. 
  9. "Collections Catalog of the Department of Paleobiology of the Smithsonian National Museum of Natural History". Smithsonian Institution. https://collections.nmnh.si.edu/search/paleo/. 
  10. "Collections Database of the Yale Peabody Museum". Yale Peabody Museum. 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=. 
  11. 11.0 11.1 11.2 11.3 11.4 11.5 11.6 Ferrón, Humberto G.; Martínez-Pérez, Carlos; Botella, Héctor (2017). "Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data" (in en). PeerJ 5: e4081. doi:10.7717/peerj.4081. ISSN 2167-8359. PMID 29230354. 
  12. Lehman, Jean-Pierre (1956), "Les arthrodires du Dévonien supérieur du Tafilalet (Sud Marocain)" (in fr), Notes et Mémoires. Service Géologique du Maroc 129: 1–170 
  13. 13.0 13.1 13.2 13.3 Carr R. K., Hlavin V. J. (2010). "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)". Zoological Journal of the Linnean Society 159 (1): 195–222. doi:10.1111/j.1096-3642.2009.00578.x. 
  14. Carr, Robert K.; William J. Hlavin (2 September 1995). "Dinichthyidae (Placodermi):A paleontological fiction?". Geobios 28: 85–87. doi:10.1016/S0016-6995(95)80092-1. Bibcode1995Geobi..28...85C. 
  15. You-An Zhu; Min Zhu (2013). "A redescription of Kiangyousteus yohii (Arthrodira: Eubrachythoraci) from the Middle Devonian of China, with remarks on the systematics of the Eubrachythoraci". Zoological Journal of the Linnean Society 169 (4): 798–819. doi:10.1111/zoj12089. 
  16. Zhu, You-An; Zhu, Min; Wang, Jun-Qing (1 April 2016). "Redescription of Yinostius major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the interrelationships of Brachythoraci". Zoological Journal of the Linnean Society 176 (4): 806–834. doi:10.1111/zoj.12356. ISSN 0024-4082. 
  17. 17.0 17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8 Denison, Robert (1978). "Placodermi". Handbook of Paleoichthyology. 2. Stuttgart New York: Gustav Fischer Verlag. pp. 128. ISBN 978-0-89574-027-4. 
  18. 18.0 18.1 18.2 18.3 18.4 18.5 Lebedev, Oleg A.; Engelman, Russell K.; Skutschas, Pavel P.; Johanson, Zerina; Smith, Moya M.; Kolchanov, Veniamin V.; Trinajstic, Kate; Linkevich, Valeriy V. (May 2023). "Structure, Growth and Histology of Gnathal Elements in Dunkleosteus (Arthrodira, Placodermi), with a Description of a New Species from the Famennian (Upper Devonian) of the Tver Region (North-Western Russia)" (in en). Diversity 15 (5): 648. doi:10.3390/d15050648. ISSN 1424-2818. 
  19. Lelièvre, Hervé (1982). "Ardennosteus ubaghsi n.g., n. sp. Brachythoraci primitif (vertébré, placoderme) du Famennien d'Esneux (Belgique)". Annales de la Société géologique de Belgique 105 (1). https://popups.uliege.be/0037-9395/index.php?id=3220. 
  20. Murray, A.M. (2000). "The Palaeozoic, Mesozoic and Early Cenozoic fishes of Africa". Fish and Fisheries 1 (2): 111–145. doi:10.1046/j.1467-2979.2000.00015.x. Bibcode2000AqFF....1..111M. 
  21. Schultz, H (1973). "Large Upper Devonian arthrodires from Iran". Fieldiana Geology 23: 53–78. doi:10.5962/bhl.title.5270. 
  22. Dennis-Bryan, Kim (1987). "A new species of eastmanosteid arthrodire (Pisces: Placodermi) from Gogo, Western Australia". Zoological Journal of the Linnean Society 90 (1): 1–64. doi:10.1111/j.1096-3642.1987.tb01347.x. 
  23. Dunkle; Lane, N.G. (1971). "Devonian fishes from California. Kirtlandia". Kirtlandia 15: 1–5. 
  24. Lua error: Internal error: The interpreter exited with status 1.Template:Dead YouTube link
  25. Carr, R, & G.L. Jackson. 2008. The Vertebrates fauna of the Cleveland member (Famennian) of the Ohio Shale. Society of Vertebrates Paleontology. 1–17.
  26. 26.0 26.1 26.2 26.3 26.4 26.5 26.6 Anderson, P.S.L.; Westneat, M. (2007). "Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator". Biology Letters 3 (1): 76–79. doi:10.1098/rsbl.2006.0569. PMID 17443970. 
  27. 27.0 27.1 27.2 27.3 27.4 27.5 Anderson, P.S.L.; Westneat, M. (2009). "A biomechanical model of feeding kinematics for Dunkleosteus terrelli (Arthrodira, Placodermi)". Paleobiology 35 (2): 251–269. doi:10.1666/08011.1. Bibcode2009Pbio...35..251A. http://projects.fieldmuseum.org/sites/default/files/DunkPaleoBio.pdf. Retrieved 29 October 2017. 
  28. Williams, Nigel (2007). "Force feeding". Current Biology 17: R3. doi:10.1016/j.cub.2006.11.057. 
  29. 29.0 29.1 Carr, Robert K. (2010). "Paleoecology of Dunkleosteus terrelli (Placodermi: Arthrodira).". Kirtlandia 57. https://www.researchgate.net/publication/235924093. 
  30. Newberry, John S. (1889). "Paleozoic fishes of North America". Monographs of the U.S. Geological Survey 16: 24. https://www.biodiversitylibrary.org/item/51025#page/5/mode/1up. 
  31. Dean, Bashford (1895). Fishes, Living and Fossil: An Outline of Their Forms and Probable Relationships. London: Macmillan and Company. p. 130. 
  32. Hussakof, Louis (1905). "Notes on the Devonian "placoderm" Dinichthys intermedius Newb.". Bulletin of the American Museum of Natural History 21: 27–36. 
  33. Anonymous (1923). "Cleveland shale fishes". Bulletin of the Cleveland Museum of Natural History 9: 36. 
  34. Hyde, Jesse E. (1926). "Collecting fossil fishes from the Cleveland Shale". Natural History 26: 497–504. 
  35. Romer, Alfred S. (1966). Vertebrate Paleontology (3rd ed.). Chicago: University of Chicago Press. p. 49. 
  36. Colbert, Edwin H. (1969). Evolution of the Vertebrates: A History of Backboned Animals Through Time (2nd ed.). Hoboken: John Wiley and Sons. p. 36. 
  37. Williams, Michael E. (1992). "Jaws: The Early Years". Explorer 34: 4–8. 
  38. Janvier, P. (2003). Early Vertebrates. Oxford: Clarendon Press. p. 12. 
  39. Young, Gavin C. (24 December 2003). "Did placoderm fish have teeth?". Journal of Vertebrate Paleontology 23 (4): 987–990. doi:10.1671/31. Bibcode2003JVPal..23..987Y. 
  40. Long, John A. (2010). The Rise of Fishes: 500 Million Years of Evolution (2nd ed.). Baltimore: Johns Hopkins University Press. pp. 88–90. 
  41. Sallan, Lauren; Galimberti, Andrew K. (13 November 2015). "Body-size reduction in vertebrates following the end-Devonian mass extinction". Science 350 (6262): 812–815. doi:10.1126/science.aac7373. PMID 26564854. Bibcode2015Sci...350..812S. 
  42. Long, John A.; Choo, Brian; Clement, Alice (31 December 2018). "The Evolution of Fishes through Geological Time". in Johanson, Zerina; Underwood, Charlie; Richter, Martha. Evolution and Development of Fishes. pp. 3–29. doi:10.1017/9781316832172.002. 
  43. Johanson, Zerina; Trinajstic, Kate; Cumbaa, Stephen; Ryan, Michael (2019). "Fusion in the vertebral column of the pachyosteomorph arthrodire Dunkleosteus terrelli ('Placodermi')". Palaeontologia Electronica 22.2.20A: 1–13. doi:10.26879/872. 
  44. "Dunkleosteus Placodermi Devonian Armored Fish from Morocco". Fossil Archives. The Virtual Fossil Museum. http://www.fossilmuseum.net/Fossil_Galleries/Fish_Devonian/Dunkleosteous/Dunkleosteus.htm. 
  45. "UWL Website". http://bioweb.uwlax.edu/bio203/f2013/peters_sadi/habitat.htm. 
  46. Ahlberg, Per; Trinajstic, Kate; Johanson, Zerina; Long, John (2009). "Pelvic claspers confirm chondrichthyan-like internal fertilization in arthrodires". Nature 460 (7257): 888–889. doi:10.1038/nature08176. PMID 19597477. Bibcode2009Natur.460..888A. 
  47. Long, J. A.; Trinajstic, K.; Young, G. C.; Senden, T. (2008). "Live birth in the Devonian period". Nature 453 (7195): 650–652. doi:10.1038/nature06966. PMID 18509443. Bibcode2008Natur.453..650L. 
  48. Snively, E.; Anderson, P.S.L.; Ryan, M.J. (2009). "Functional and ontogenetic implications of bite stress in arthrodire placoderms". Kirtlandia 57. https://www.biodiversitylibrary.org/page/51811342#page/60/mode/1up. 

Lua error: Internal error: The interpreter exited with status 1.

Further reading

External links

Wikidata ☰ Q131039 entry


Lua error: Internal error: The interpreter exited with status 1.