Holdenius was a large arthrodire, reaching lengths of around 3 m (9.8 ft).[1] This placoderm is known only from isolated jaw bones,[2] and little is known about it except that it is relatively morphologically similar to its more famous relative Dunkleosteus, with which it shared a spatial and temporal range.
Holdenius was a piscivorous animal that used its sharp shearing gnathal plates to seize and cleave its prey into manageable pieces. One articulated specimen of this placoderm from the Upper Devonian Cleveland Shale was preserved adjacent to the remains of its prey; a Ctenacanthchondrichthyan, which had been bitten in half. Considering its prey was over half its size, it can be inferred that Holdenius was an exceptionally aggressive nektonic predator. An anterior dorsal spine from the ctenacanth was found lodged in the palate and extending into the braincase of the Holdenius, likely killing it instantly.[3]
^M. C. Hansen and R. H. Mapes, “A Predator–Prey Relationship between Sharks and Cephalopods in the Late Paleozoic,” in Evolutionary Paleobiology of Behavior and Coevolution , Ed. by A.J. Boucot (Elsevier, London, 1990), pp. 189–199.
^Carr, Robert. (2009). THE VERTEBRATE FAUNA OF THE CLEVELAND MEMBER (FAMENNIAN) OF THE OHIO SHALE.
^Brett, Carlton & Walker, Sally. (2002). Predators and Predation in Paleozoic Marine Environments. Paleontological Society Papers. 8. 10.1017/S1089332600001078.
^Carr, R.K.; Hlavin, W.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.
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holdenius, extinct, genus, arthrodire, placoderm, fish, which, lived, during, late, devonian, period, temporal, range, famennian, preꞒ, nartist, reconstruction, holdeni, prey, unidentified, ctenacanth, chondrichthyanscientific, classificationkingdom, animaliap. Holdenius is an extinct genus of arthrodire placoderm fish which lived during the Late Devonian period HoldeniusTemporal range Famennian PreꞒ Ꞓ O S D C P T J K Pg NArtist s reconstruction of Holdenius holdeni and its prey an unidentified Ctenacanth chondrichthyanScientific classificationKingdom AnimaliaPhylum ChordataClass PlacodermiOrder ArthrodiraSuborder BrachythoraciClade EubrachythoraciClade PachyosteomorphiClade AspinothoracidiGenus HoldeniusDunkle and Bungart 1942Type speciesHoldenius holdeniDunkle and Bungart 1942Description EditHoldenius was a large arthrodire reaching lengths of around 3 m 9 8 ft 1 This placoderm is known only from isolated jaw bones 2 and little is known about it except that it is relatively morphologically similar to its more famous relative Dunkleosteus with which it shared a spatial and temporal range Holdenius was a piscivorous animal that used its sharp shearing gnathal plates to seize and cleave its prey into manageable pieces One articulated specimen of this placoderm from the Upper Devonian Cleveland Shale was preserved adjacent to the remains of its prey a Ctenacanth chondrichthyan which had been bitten in half Considering its prey was over half its size it can be inferred that Holdenius was an exceptionally aggressive nektonic predator An anterior dorsal spine from the ctenacanth was found lodged in the palate and extending into the braincase of the Holdenius likely killing it instantly 3 Holdenius is a monospecific genus with only one specimen ever discovered Previously classified as belonging to the family Dunkleosteidae it is now considered to be a member of Aspinothoracidi the sister clade to Dunkleosteoidea 4 References Edit M C Hansen and R H Mapes A Predator Prey Relationship between Sharks and Cephalopods in the Late Paleozoic in Evolutionary Paleobiology of Behavior and Coevolution Ed by A J Boucot Elsevier London 1990 pp 189 199 Carr Robert 2009 THE VERTEBRATE FAUNA OF THE CLEVELAND MEMBER FAMENNIAN OF THE OHIO SHALE Brett Carlton amp Walker Sally 2002 Predators and Predation in Paleozoic Marine Environments Paleontological Society Papers 8 10 1017 S1089332600001078 Carr R K Hlavin W 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 This article related to a Devonian fish is a stub You can help Wikipedia by expanding it vte This article about a placoderm is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Holdenius amp oldid 1092787695, wikipedia, wiki, book, books, library,
