Ischyodus Explained

Ischyodus (from Greek, Modern (1453-);: ισχύς, 'power' and Greek, Modern (1453-);: ὀδούς '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, 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 possibly belongs long specimen.^[4]

External links

• Image of a ratfish, Ischyodus rayhaasi, mandible

Notes and References

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 . en . 22 . 4 . 364–372 . 10.2517/2018PR004 . 133941390 . 1342-8144.
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 . 10.4202/app.00859.2020 . 0567-7920. free .
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 . English . 22 . 4 . 364–372 . 10.2517/2018PR004 . 133941390 . 1342-8144.