The oldest baleen-bearing whales? Maybe.

Nobile et al 2025 described
“The evolution of baleen whales (Mysticeti) comprises two main phases, namely, (i) a Paleogene phase, which saw the diversification of stem lineages, and (ii) a Neogene phase, dominated by modern-looking, toothless, baleen-bearing forms in the monophyletic group Chaeomysticeti.”

This is incorrect based on taxon exclusion. Mysticetes arose from hippos and desmotylians in the large reptile tree (LRT, 2338 taxa) apart from toothed whales evolving to become odontocetes.

Hippos and desmostylians are not mentioned in the Nobile et al text. This paper was approved by editors and referees intent on keeping the monophyletic Cetacea myth alive. This is why universities can be bad for paleontology. Do you want to pay tuition for outdated information?

There is no such clade as ‘Chaemysiceti’ when pertinent taxa are added to analysis. This clade was invented to allow certain toothed whales into the base of the Mysticeti. Don’t fall for that trick. Test this yourself.

Nobile et al continued,
“This dark age [in the authors’ headline] occurred between 23 and ~18 Ma and is apparently detected worldwide, except in Zealandia.”

Desmostylus and Behemotops both precede the Miocene. So does Cornwallius. Late Miocene Miiocaperea is not mentioned, but cited. Extant Caperea has one mention. Miocene Neoparadoxia and Palaeoparadoxia are not mentioned or cited. Both lived in the Miocene.

So the authors’ ‘Dark Age’ is a self-inflicted wound based on taxon exclusion, still the number one problem in paleotology.

The LRT minimized taxon exclusion by including 2338 taxa.

“Here, we report on a new mysticete fossil from the Lower Miocene (Burdigalian: ~19.2 Ma) strata of the Chilcatay Formation cropping out at the newly discovered locality of Cerro Tiza (East Pisco Basin, Peru), which represents a limited but precious testament from the last phase of the baleen whale dark age.”

The Cerro Tiza mysticete specimen, CTZ 02, is a posterior skull lacking a rostrum, but having a partial rostral endocast.

The Zamaca mysticete specimen, ZM 152, is not much better preserved.

“Consensus on the phylogeny of the baleen-bearing whales (Chaeomysticeti) is still wanting, as the continuous discovery of new fossils and the inclusion or exclusion of specific taxa in different phylogenetic analyses has led different authors to propose several alternative phylogenetic reconstructions”

The ten authors are all barking up the wrong tree by excluding desmostylians, hippos and flat-headed oreodonts.

Mysticetes are not related to odontocetes. The LRT recovered that in 2016.

That is why some papers are doomed from the first key-stroke.
Don’t be like these whale experts who rely on traditional myths. Show some curiosity and drive. Make sure your cladogram includes all pertinent taxa.

If you google: ‘oldest known baleen whale‘
you get toothy Mystacodon (Fig 2) from the Eocene. In the LRT, Mystacodon is not related to mysticetes, but is recovered in the lineage of archaeocetes and odontocetes.

Second paper on mysticetes: Tanaka 2022
suffered from the same taxon exclusion problems.

If you wonder why paleo experts don’t wander from textbook myths to become academic rebels by simply adding pertinent taxa, see this blogpost.

Editors note:
After 370 days of housekeeping the mammal subset of the LRT the corresponding pages of taxa at ReptileEvolution.com have been updated with regard to their index columns. Some old text may still linger that relied on old data and smaller taxon lists. I’ll get around to it soon.

References
Nobile F et al (10 co-authors) 2025. Surviving a Dark Age: The Oldest Baleen-Bearing Whales (Cetacea: Chaeomysticeti) of Pacific South America (Lower Miocene, Peru). Life 2025, 15(3), 452; https://doi.org/10.3390/life15030452
Tanaka Y 2022. Rostrum morphology and feeding strategy of the baleen whale indcate that right whales and pygmy right whales became skimmers independently. Royal Society Open Science 9: 221353. https://doi.org/10.1098/rsos.221353

wiki/Baleen_whale

Source: https://pterosaurheresies.wordpress.com/2025/04/22/the-oldest-baleen-bearing-whales-maybe/