Eosaurichthys Explained

Eosaurichthys ("dawn Saurichthys") is an extinct genus, or potentially subgenus, of marine saurichthyid ray-finned fish that lived during the late Permian epoch (Changhsingian age) to potentially the Early Triassic epoch (Olenekian).^[1] It is one of the earliest saurichthyid genera known from the fossil record. If E. madagascariensis is a member of this genus, then it appears to have survived the Permian-Triassic extinction event.

Eosaurichthys is often treated as a subgenus of Saurichthys rather than a genus, with its type species referred to as Saurichthys (Eosaurichthys) chaoi.^[2]

Up to two species are known:^[3]

• E. chaoi Liu & Wei, 1988 - Late Permian (Changhsingian) of China (Changxing Formation)
• E. madagascariensis (Piveteau, 1945) - Early Triassic (Olenekian) of Madagascar (Sakamena Formation)^{[4] [5]}

Saurichthyid remains tentatively referred to E. madagascariensis are known from Anisian-aged freshwater beds of the Yerrapalli Formation in India.

Appearance

Eosaurichthys closely resembles its daughter genus, Saurichthys, in both form and morphology. Its body is fully covered by scales, while in Saurichthys the scale cover is reduced.^{[2] [6]}

See also

• Prehistoric fish
• List of prehistoric bony fish

Notes and References

1. Sepkoski . Jack . A compendium of fossil marine animal genera . Bulletins of American Paleontology . 364 . 560 . 2002 . 2009-04-24 . dead . https://web.archive.org/web/20110723131237/http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class . 2011-07-23 .
2. Tintori . Andrea . 2013 . A new species of Saurichthys (Actinopterygii) from the Middle Triassic (early Ladinian) of the northern Grigna Mountain (Lombardy, Italy) . Rivista Italiana di Paleontologia e Stratigrafia . 119 . 3 . 287–302 . 10.13130/2039-4942/6041 . free.
3. Web site: PBDB Taxon . 2025-01-20 . paleobiodb.org.
4. Maxwell, E.E. . Romano, C. . Wu, F.-X. . amp . 2021 . Regional disparity in the axial skeleton of Saurichthyidae and implications for axial regionalization in non‐teleostean actinopterygians. . Journal of Zoology . 315 . 29–41 . 10.1111/jzo.12878 . free.
5. Silvio Renesto . Fabio Magnani . Rudolf Stockar . 2021 . A new species of Saurichthys (Actinopterygii: Saurichtydae) from the Middle Triassic of Monte San Giorgio . Rivista Italiana di Paleontologia e Stratigrafia . 127 . 1 . 49–71 . 10.13130/2039-4942/15143 . free.
6. Romano C., Kogan I., Jenks J., Jerjen I., Brinkmann W. . 2012 . Saurichthys and other fossil fishes from the late Smithian (Early Triassic) of Bear Lake County (Idaho, USA), with a discussion of saurichthyid palaeogeography and evolution . Bulletin of Geosciences . 87 . 543–570 . 10.3140/bull.geosci.1337 . free.