Ischyodus

Ischyodus; Temporal range: 176–23 Ma PreꞒ Ꞓ O S D C P T J K Pg N Middle Jurassic to Miocene
	Ischyodus quenstedti
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Holocephali
Order:	Chimaeriformes
Family:	Callorhinchidae
Genus:	†Ischyodus; Egerton, 1843
Species
	Ischyodus bifurcatus; Ischyodus brevirostris; Ischyodus dolloi; Ischyodus gubkini; Ischyodus incisus; Ischyodus latus; Ischyodus lonzeensis; Ischyodus minor; Ischyodus mortoni; Ischyodus planus; Ischyodus rayhaasi; Ischyodus thurmanni; Ischyodus townsendi; Ischyodus williamsae; Ischyodus yanshini; Ischyodus zinsmeisteri;

Ischyodus (from Greek: ισχύς ischýs, 'power' and Greek: ὀδούς odoús 'tooth') is an extinct genus of chimaera. It is the most diverse and long-lived chimaera genus, with over 39 species found worldwide spanning over 140 million years from the Middle Jurassic to the Miocene.^[1] Complete specimens of I. quenstedti from the Late Jurassic of Germany most closely resemble the genus Callorhinchus amongst living chimaera genera.^[2] It is sometimes placed in the "Edaphodontidae", a unclearly defined group of chimaera with an uncertain position within the clade,^[1] while other authors place it into Callorhinchidae along with Callorhinchus.^[3]

Based on complete specimen, total length is 21 times larger than mesiodistal length of mandibular tooth plate. For example, I. bifurcatus with mandibular plate length of 3.2 in (8.2 cm) possibly belongs 5 ft 8 in (1.72 m) long specimen.^[4]

References

^ ^a ^b Johnson-Ransom, Evan D.; Popov, Evgeny V.; Deméré, Thomas A.; Shimada, Kenshu (October 2018). "The Late Cretaceous Chimaeroid Fish, Ischyodus bifurcatus Case (Chondrichthyes: Holocephali), from California, USA, and Its Paleobiogeographical Significance". Paleontological Research. 22 (4): 364–372. doi:10.2517/2018PR004. ISSN 1342-8144. S2CID 133941390.
^ Popov, E. V., Duffin, C. J., Tischlinger, H. and Atuchin, A., 2013: Reconstructions of the German Plattenkalk (Late Jurassic) chimaeroid fishes (Holocephali, Chimaeroidei). In, Schwarz, C. and Kriwet, J. eds., Sixth International Meeting on Mesozoic Fishes: Diversification and Diversity Patterns. Abstracts, p. 56. Verlag Friedrich Pfeil, Munich
^ Otero, Rodrigo; Figueroa Bravo, Constanza; Soto Huenchuman, Paula; Fernández-Collemann, Sara; Valenzuela Toro, Ana; Gutstein, Carolina (2021). "First record of Ischyodus (Chondrichthyes, Holocephali) from the Upper Jurassic of southwestern Gondwana". Acta Palaeontologica Polonica. 66. doi:10.4202/app.00859.2020. ISSN 0567-7920.
^ Johnson-Ransom, Evan D.; Popov, Evgeny V.; Deméré, Thomas A.; Shimada, Kenshu (2018-10-01). "The Late Cretaceous Chimaeroid Fish, Ischyodus bifurcatus Case (Chondrichthyes: Holocephali), from California, USA, and Its Paleobiogeographical Significance". Paleontological Research. 22 (4): 364–372. doi:10.2517/2018PR004. ISSN 1342-8144. S2CID 133941390.

External links

Image of a ratfish, Ischyodus rayhaasi, mandible

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[:0-1] Johnson-Ransom, Evan D.; Popov, Evgeny V.; Deméré, Thomas A.; Shimada, Kenshu (October 2018). "The Late Cretaceous Chimaeroid Fish, Ischyodus bifurcatus Case (Chondrichthyes: Holocephali), from California, USA, and Its Paleobiogeographical Significance". Paleontological Research. 22 (4): 364–372. doi:10.2517/2018PR004. ISSN 1342-8144. S2CID 133941390.

[2] Popov, E. V., Duffin, C. J., Tischlinger, H. and Atuchin, A., 2013: Reconstructions of the German Plattenkalk (Late Jurassic) chimaeroid fishes (Holocephali, Chimaeroidei). In, Schwarz, C. and Kriwet, J. eds., Sixth International Meeting on Mesozoic Fishes: Diversification and Diversity Patterns. Abstracts, p. 56. Verlag Friedrich Pfeil, Munich

[3] Otero, Rodrigo; Figueroa Bravo, Constanza; Soto Huenchuman, Paula; Fernández-Collemann, Sara; Valenzuela Toro, Ana; Gutstein, Carolina (2021). "First record of Ischyodus (Chondrichthyes, Holocephali) from the Upper Jurassic of southwestern Gondwana". Acta Palaeontologica Polonica. 66. doi:10.4202/app.00859.2020. ISSN 0567-7920.

[4] Johnson-Ransom, Evan D.; Popov, Evgeny V.; Deméré, Thomas A.; Shimada, Kenshu (2018-10-01). "The Late Cretaceous Chimaeroid Fish, Ischyodus bifurcatus Case (Chondrichthyes: Holocephali), from California, USA, and Its Paleobiogeographical Significance". Paleontological Research. 22 (4): 364–372. doi:10.2517/2018PR004. ISSN 1342-8144. S2CID 133941390.

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Ischyodus Temporal range: 176–23 Ma PreꞒ Ꞓ O S D C P T J K Pg N Middle Jurassic to Miocene

Ischyodus quenstedti
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Holocephali
Order:	Chimaeriformes
Family:	Callorhinchidae
Genus:	†Ischyodus Egerton, 1843
Species
Ischyodus bifurcatus Ischyodus brevirostris Ischyodus dolloi Ischyodus gubkini Ischyodus incisus Ischyodus latus Ischyodus lonzeensis Ischyodus minor Ischyodus mortoni Ischyodus planus Ischyodus rayhaasi Ischyodus thurmanni Ischyodus townsendi Ischyodus williamsae Ischyodus yanshini Ischyodus zinsmeisteri