SCOTCAT.COM
your internet guide to all things catfish
| Corydoras revelatus (Hoplisoma revelatum) a Fossil Discovery |
by Allan James |
Green Tertiary rock
The last of the dinosaurs disappeared from the earth around 65 million years ago so our fossil friend Corydoras revelatus (now Hoplisoma revelatum) lived in the Tertiary period just after this, alongside the hairy mammal. It was discovered in Argentina in Sunchal, Juyuy province, by a well known entomologist, Professor T.D.A.Cockerell of the University of Colorado, Boulder, in 1925. He was actually searching along with his wife for fossil insects at the time before he came across our plated friend. 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, 1925. It is now housed in the British Natural History Museum, London.
Hoplisoma revelatum fossil
The entomologist T.D.A."Theo" Cockerell (1866-1948) was better known for his work on the wild bees of Colorado and wrote many papers on these insects. He has even a mosquito from Florida named after him. Theo was the brother of the noted scholar Sir Sydney Cockerell who was high up the ladder of British society at the time.
Fossil with information tag
How is a fossil formed?. Well this Corydoras/Hoplisoma died and was covered by the mud at the bottom of the river. The river would have dried up and the sediment compressed and hardened. The next process would be minerals which would seep through the bones which gradually change into rock. Millions of years later the fossil appears as the covering rock is worn away by wind and water. 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.
Acknowledgment: Jim Makin for supplying images for this article. References: 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. Photo Credits: Top 2: Eric McCabe Bottom: Steve Pritchard |
question
I am often asked is "what age does does a Corydoras
live to" this set me thinking of the origins of
our little whiskered friends and the discovery that
they lived on our earth (well in the water anyway!)
at least 50-60 million years ago. 
If you would like to contribute an article, please e-mail me. You will of course be credited for your work.
If you would like to donate any denomination of money to the site just click the above link button. All proceeds will go to running the site and hopefully to keep it going for a few years yet.
Print or e-mail this factsheet below
