Corydoras revelatus is an extinct species of callichthyid catfish known from a single specimen found in Late Paleocene strata of the Mais Gordo Formation in Salta, Argentina. According to chronological dating of the strata, the fossil specimen is about 58.2–58.5 million years old.[1][2]

Corydoras revelatus
Temporal range: Late Paleocene,
~58.5–58.2 Ma
Life restoration
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Callichthyidae
Genus: Corydoras
Species:
C. revelatus
Binomial name
Corydoras revelatus
Cockerell, 1925

Compared to modern species, C. revelatus has a short, comparatively rounded head, and rather low-set eyes. Although the species's position within the genus Corydoras is tentative and unresolved, its anatomy confirms that it is a member of the subfamily, Corydoradinae, and demonstrates that the callichthyids had already diverging or diversifying before the end of the Paleocene.[1][2]

Corydoras revelatus is the oldest known definitive fossil loricarioid.[2] The Moroccan Afrocascudo, deriving from the Late Cretaceous (Cenomanian, ~100–95 Ma) Kem Kem Group, has been initially described as the oldest known member in 2024.[3] Some researchers suggest that this taxon might actually represent a juvenile obaichthyid lepisosteiform, possibly a junior synonym of Obaichthys,[4] though this has been disputed based on the complete ossification of the bones indicating full maturity and the absence of important holostean characters.[5]

References

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  1. ^ a b Cockerell, T. D. A. (1925-10-30). "A Fossil Fish of the Family Callichthyidae". Science. 62 (1609): 397–398. doi:10.1126/science.62.1609.397.c. ISSN 0036-8075.
  2. ^ a b c Lundberg, John G.; Sullivan, John P.; Rodiles-Hernández, Rocío; Hendrickson, Dean A. (2007-06-01). "Discovery of African roots for the Mesoamerican Chiapas catfish, Lacantunia enigmatica, requires an ancient intercontinental passage" (PDF). Proceedings of the Academy of Natural Sciences of Philadelphia. 156 (1): 39–53. doi:10.1635/0097-3157(2007)156[39:DOARFT]2.0.CO;2. ISSN 0097-3157. Archived from the original (PDF) on 2009-03-26.
  3. ^ Brito, Paulo M.; Dutheil, Didier B.; Gueriau, Pierre; Keith, Philippe; Carnevale, Giorgio; Britto, Marcelo; Meunier, François J.; Khalloufi, Bouziane; King, Andrew; de Amorim, Pedro F.; Costa, Wilson J. E. M. (2024). "A Saharan fossil and the dawn of Neotropical armoured catfishes in Gondwana". Gondwana Research. 132: 103–112. Bibcode:2024GondR.132..103B. doi:10.1016/j.gr.2024.04.008.
  4. ^ Britz, R.; Pinion, Amanda K.; Kubicek, Kole M.; Conway, Kevin W. (2024). "Comment on "A Saharan fossil and the dawn of Neotropical armoured catfishes in Gondwana" by Brito et al". Gondwana Research. doi:10.1016/j.gr.2024.06.014.
  5. ^ Brito, Paulo M.; Dutheil, Didier B.; Keith, Philippe; Carnevale, Giorgio; Meunier, François J.; Khalloufi, Bouziane; Gueriau, Pierre (2024). "A reply to a comment on Brito et al., 2024, A Saharan fossil and the dawn of the Neotropical armoured catfishes in Gondwana by Britz, Pinion, Kubicek and Conway". Gondwana Research. doi:10.1016/j.gr.2024.06.013.