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Steve Pritchard (1) Eric McCabe (2)

This was the first fossil of Corydoras/Hoplisoma which was discovered in Tertiary rock by Professor T. D. A. Cockerell of the University of Colorado, Boulder in 1925. The discovery was in Sunchal, Juyuy province, from the Maiz Formation of Argentina dating from the late Paleocene period (61-66 million years). Lineage: If alive today this species would be placed in Lineage 1. A revision would have had them they staying as Corydoras (Lacépède, 1803) with the type species of C. geoffroy La Cépède, 1803. As of the latest revision (Dias et al 2024) the fossil Corydoras revalatus has now been placed in Lineage 9 and has the new genus name of Hoplisoma and a change to the specific name to revelatum. Remarks: The green Tertiary rock measured 32mm and the imprint 27mm and it bears the outline of a Corydoras/Hoplisoma (Sands,D. 1983) What was noticed was that a flaw in the rock suggested that the dorsal spine was longer (Isbrücker) and the problem of the one dimensional shape of the fossil made it the subject of a new species, Corydoras revelatus (now Hoplisoma revelatum) Cockerell, 1926. It is now housed in the British Natural History Museum, London.

Fossil Cory

Corydoras revelatus

Callichthyidae

South America: Argentina, Jujuy district, Sunchal, from the Maiz Formation.

2.7cm (1¼ins)

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Angelica C Dias, Luiz F C Tencatt, Fabio F Roxo, Gabriel de Souza da Costa Silva, Sérgio A Santos, Marcelo R Britto, Martin I Taylor, Claudio Oliveira, Phylogenomic analyses in the complex Neotropical subfamily Corydoradinae (Siluriformes: Callichthyidae) with a new classification based on morphological and molecular data, Zoological Journal of the Linnean Society, 2024;, zlae053.
Sands, David; Catfishes of the World, Volume 1 Callichthyidae.