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==Description==
==Description==
''Holdenius'' was a large arthrodire, reaching lengths of around {{convert|3|m|ft|1|abbr=on}}<ref>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.</ref>. It is morphologically similar to its more famous relative ''[[Dunkleosteus]]'', with which it shared a spatial and temporal range.
''Holdenius'' was a large arthrodire, reaching lengths of around {{convert|3|m|ft|1|abbr=on}}<ref>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.</ref>. This placoderm is known only from isolated jaw bones<ref>Carr, Robert. (2009). THE VERTEBRATE FAUNA OF THE CLEVELAND MEMBER (FAMENNIAN) OF THE OHIO SHALE.</ref>, 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.


Like most other [[dunkleosteid]]s, ''Holdenius'' was an undoubtedly 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.<ref>Brett, Carlton & Walker, Sally. (2002). Predators and Predation in Paleozoic Marine Environments. Paleontological Society Papers. 8. 10.1017/S1089332600001078.</ref>
Like most other [[dunkleosteid]]s, ''Holdenius'' was an undoubtedly 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.<ref>Brett, Carlton & Walker, Sally. (2002). Predators and Predation in Paleozoic Marine Environments. Paleontological Society Papers. 8. 10.1017/S1089332600001078.</ref>

Revision as of 13:16, 26 March 2021

Holdenius
Temporal range: Late Famennian
Artist's reconstruction of Holdenius holdeni and its prey, an unidentified Ctenacanth chondrichthyan
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Placodermi
Order: Arthrodira
Suborder: Brachythoraci
Clade: Aspinothoracidi
Genus: Holdenius
Dunkle and Bungart, 1942
Type species
Holdenius holdeni
Dunkle and Bungart, 1942

Holdenius is an extinct genus of arthrodire placoderm fish which lived during the Late Devonian period.

Description

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.

Like most other dunkleosteids, Holdenius was an undoubtedly 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]

References

  1. ^ 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.
  2. ^ Carr, Robert. (2009). THE VERTEBRATE FAUNA OF THE CLEVELAND MEMBER (FAMENNIAN) OF THE OHIO SHALE.
  3. ^ Brett, Carlton & Walker, Sally. (2002). Predators and Predation in Paleozoic Marine Environments. Paleontological Society Papers. 8. 10.1017/S1089332600001078.

Template:Dunkleosteidae