Fossil loricariid in Africa

[Silurus]

Brito, PM, DB Dutheil, P Gueriau, P Keith, G Carnevale, M Britto, FJ Meunier, B Khalloufi, A King, PF de Amorim & WJEM Costa, 2024. A Saharan fossil and the dawn of Neotropical armoured catfishes in Gondwana. Gondwana Research doi: 10.1016/j.gr.2024.04.008.

𝗔𝗯𝘀𝘁𝗿𝗮𝗰𝘁
Siluriformes are considered as primarily freshwater and have frequently been a model for the study of historical biogeography. Among catfishes, the most diverse clade is the Loricarioidei, a Neotropical group for which the fossil record extends back to the Palaeocene of Argentina.
Here we describe a fossil from the early Late Cretaceous of Morocco, exhibiting typical morphological traits of the Loricariidae. A phylogenetic analysis integrating morphological characters with a multigene database for the main loricarioid lineages and outgroups highly supports inclusion of the fossil within the Loricariidae. A time-calibrated analysis corroborates the origin of loricarioids at about 112 MYA.
The presence of this loricariid in Africa provides evidence that loricarioids have diversified before the separation of Africa and South America. The Moroccan loricariid shows an ancient evolutionary history that, in Africa, ended in the Late Cretaceous but persisted in South America, later surviving the K/Pg extinction.

[Jools]

This is interesting and I note the name Afrocascudo saharaensis for the fossil.

Thanks for posting,

Jools

[Kirin]

I'm surprised this paper hasn't got more publicity. It's fascinating and kind of changes what we knew about the group.

[bekateen]

The original interpretation (that this is a Loricariid) might be incorrect. Read this comment:

R. Britz, A.K. Pinion, K.M. Kubicek, K.W. Conway, Comment on “A Saharan fossil and the dawn of Neotropical armoured catfishes in Gondwana” by Brito et al, Gondwana Research (2024), doi:https://doi.org/10.1016/j.gr.2024.06.014

https://www.sciencedirect.com/science/a ... 7X24001795

A recent paper by Brito et al. (2024) described a new fossil genus and species, Afrocascudo saharensis, of what the authors considered to represent a member of the highly diverse catfish family Loricariidae... We downloaded the high resolution images accompanying [the paper]... and studied them in detail... we initially discovered a small error in the data matrix they used to analyze the phylogenetic position of their putative loricariid... [the] inconsistencies led us to scrutinize their paper more thoroughly and we conclude that the fossil Afrocascudo is not a loricariid but a juvenile lepisosteiform, most likely of the fossil gar genus Obaichthys... The arguments for our conclusion are presented and discussed here.

[bathyclarias]

And...the original authors' response to this comment:
P. Brito, D. Dutheil, P. Keith, G. Carnevale, F. Meunier, B. Khalloufi, P. Gueriau, A reply to a comment on, A Saharan fossil and the dawn of the Neotropical armoured catfishes in Gondwana by Britz, Pinion, Kubicek and Conway
DOI: https://doi.org/10.1016/j.gr.2024.06.013

https://www.sciencedirect.com/science/a ... 7X24001801

Abstract
Afrocascudo saharaensis Brito et al. (2024) is an armoured actinopterygian fish from the early Late Cretaceous (Cenomanian, ~100–95 million years) Jbel Oum Tkout locality (OT1) of Morocco. The fossil is known by a single specimen, fragmented in three pieces that have been prepared using resin transfer and removal of the clayey matrix. Optical microscopy observations and state-of-the-art imaging techniques including synchrotron Xray tomography allowed Brito et al. (2024) to recognise a number of synapomorphies unequivocally assigning the fossil to Loricarioidei and Loricariidae catfishes, a result further supported by phylogenetic analyses. Britz et al. (2024) question several of Brito et al.’s anatomical interpretations and argue that the fossil A. saharaensis is not a loricariid or even a teleost but an holostean. Here, we show how their arguments are based on erroneous anatomical reinterpretations of some of Brito et al.’s data. Therefore, and this is herein reinforced, A. saharaensis still stands as the earliest known occurrence of an armoured catfish, and more generally of a catfish, also providing evidence that loricarioids have diversified before the separation of Africa and South America.

[bekateen]

And...the original authors' response to this comment:

This is how science is done (albeit hopefully without the finger-pointing).

Cheers,
Eric

[Bas Pels]

Can anyone explain how A saharensis can be "not [...] even a teleost" but further "A. saharaensis still stands as the earliest known occurrence of an armoured catfish"

The group Teleostei is of a higher level then catfish, and thus all catfish are teleosts

[Silurus]

If you read the reply carefully, Brito et al. (20204) are saying that Britz et al. (2024) assert that A. saharensis is not a teleost. This is a point they disagree, and they reaffirm that it is indeed a catfish (and a teleost).

[Jools]

1-2-3-4 I declare a fossil war.

Rather daft intro by me, but this is great stuff. And it's happening in as close as real-time as you get in this type of thing. I just wish I could read it without having to pay for it. I did glean than the opposing authors have published before on ancient gars.

Will be interesting to see how it works out.

Cheers,

Jools

[bekateen]

I just wish I could read it without having to pay for it.

So let it be written. So let it be done!

Cheers, Eric