Eriptychiida
Temporal range: Late Ordovician,
Specimen of Eriptychius americanus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Infraphylum: Agnatha
Class: †Pteraspidomorphi
Subclass: †Heterostracomorphi
Infraclass: †Eriptychiida
Tarlo 1962
Order: †Eriptychiiformes
Ørvig 1958[1]
Families
  • Eriptychiidae
  • Oniscolepididae

Eriptychiida is an extinct marine taxon of vertebrate in the group Pteraspidomorphi.

The order contains the genus, Eriptychius, and fossilized specimens from this genus have been found in the Gull River Formation of Ontario, the Harding Formation of Colorado, and the Bighorn Dolomite of Wyoming. The group contains two documented species: Eriptychius americanus and Eriptychius orvigi.

Characteristics

The structure of the dentine of eriptychiids is in many respects closer to that of heterostracans that to that of astraspids. This is the only argument to place them, as the closest relatives to heterostracans, among the Ordovician vertebrates. However, eriptychiids differ from all other pteraspidomorphs in having a massively calcified endoskeleton, pervaded by canals for blood vessels.

Taxonomy

  • Order †Eriptychiiformes Ørvig 1958[2][3][4]
    • Genus ?†Eleochera Sansom & Smith 2005
    • Family †Eriptychiidae Tarlo 1962
      • Genus †Eriptychius Walcott 1892
    • Family †Oniscolepididae Märss & Karatajūtė-Talimaa 2009
      • Genus †Kallostrakon Lankester 1870
      • Genus †Oniscolepis Pander 1856 non Groß 1961 [Strosipherus Pander 1856]

In study at 2023, Eriptychius is placed just under Vertebrata, not considering class or order.[5]

See also

References

  1. ↑ Ørvig, T. 1958. Pycnaspis splendens, new genus, new species, a new ostracoderm from the Upper Ordovician of North America. Proceedings of the United States National Museum 108(3391): 1-23. DOI: 10.5479/si.00963801.108-3391.1
  2. ↑ Haaramo, Mikko (2003). "Pteraspidomorphi". in Mikko's Phylogeny Archive. After Carroll, 1988, and Janvier, 1997. Retrieved 26 October 2013.
  3. ↑ Nelson, Joseph S.; Grande, Terry C.; Wilson, Mark V. H. (2016). Fishes of the World (5th ed.). John Wiley & Sons. ISBN 9781118342336.
  4. ↑ van der Laan, Richard (2018). "Family-group names of fossil fishes" (PDF). European Journal of Taxonomy (466): 1–167. doi:10.5852/ejt.2018.466.
  5. ↑ Dearden, Richard P.; Lanzetti, Agnese; Giles, Sam; Johanson, Zerina; Jones, Andy S.; Lautenschlager, Stephan; Randle, Emma; Sansom, Ivan J. (2023-09-20). "The oldest three-dimensionally preserved vertebrate neurocranium". Nature: 1–6. doi:10.1038/s41586-023-06538-y. ISSN 1476-4687. PMC 10533405.


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