Iniopterygiformes

Iniopterygiformes
Temporal range: Carboniferous
Iniopteryx rushlaui
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Holocephali
Order: †Iniopterygiformes
Zangerl & Case, 1973
Families

Iniopterygiformes (Originally spelled Iniopterygia and sometimes informally abbreviated as "iniops")[1][2][3] is an extinct order of cartilaginous fish known only from the Carboniferous period of the United States. Iniopterygians are characterized by large, superficially wing-like pectoral fins positioned upwards behind the head, from which the name of the group (translated as "nape fin")[1] is derived. Iniopterygians are also noted to possess proportionally large skulls and eyes, armor plates composed of dentin, and "tooth-whorls" of fused teeth. Their elongated pectoral fins bore large, denticle-covered spines, and they are thought to have used them to swim using a "flying" motion.[1][4] The iniopterygians were comparatively small chondrichthyans, with the largest species reaching only 50 cm (20 in) in length.[1]

3D scan of the skull and pectoral region of the sibyrinchid Iniopera richardsoni

The group is regarded as a relative of modern chimaeras, and is placed in the subclass Holocephali. Two families of iniopterygians are recognized; the Sibyrhinchidae and the Iniopterygidae, with the latter containing only the genera Iniopteryx and Promyxele and the former housing all other named genera.[3][5] The classification of the iniopterygians, both with eachother and with other groups of holocephalan, has been considered problematic.[5]

Genera

References

  1. ^ a b c d Zangerl, Rainer; Case, Gerard (1973). "Iniopterygia : a new order of Chondrichthyan fishes from the Pennsylvanian of North America". Fieldiana. 6: 1–67. doi:10.5962/bhl.title.5158 – via Biodiversity Heritage Library.
  2. ^ Ewing, Susan (2017). Resurrecting the Shark: A Scientific Obsession and the Mavericks Who Solved the Mystery of a 270-Million-Year-Old Fossil. New York: Pegasus Books. ISBN 978-1-68177-343-8.
  3. ^ a b "PBDB Taxon". paleobiodb.org. Retrieved 2025-01-15.
  4. ^ Zangerl, Rainer (1981). Handbook of Paleoichthyology, Chondrichthyes I: Paleozoic Elasmobranchii. Vol. 3A. Verlag Dr. Friedrich Pfeil. ISBN 978-3-437-30337-1.
  5. ^ a b Nelson, Joseph S. (2016). Fishes of the world (5th ed.). Hoboken, New Jersey: John Wiley & Sons. ISBN 978-1-119-17484-4.

Further reading

  • Richard Lund and Eileen D. Grogan: Relationships of the Chimaeriformes and the Basal Radiation of the Chondrichthyes, Reviews in Fish Biology and Fisheries 7: 65-123. 1997