SVP 2021 abstracts – 25: Mysticete feeding modes

Brand and Uhen 2021 report:
“The timing of the evolution of baleen in mysticetes remains unresolved, despite an abundance of early mysticete fossils.”

The problem is: taxon exclusion. These authors still hold on to the myth that the clade Cetacea is monophyletic, that baleen whales arose, somehow, from toothed whales. In the large reptile tree (LRT, 1992 taxa) mysticetes evolved from desmostylians (Fig. 1), a grade or clade traditionally omitted from whale studies.

This is false. The authors are forcing in an invalid outgroup taxon (Aetiocetus). Add taxa to separate toothed whales from baleen whales back to Jurassic tree shrews.

“Recent studies have suggested that tooth loss and the evolution of baleen are not necessarily correlated events, and a variety of disparate feeding modes have been proposed for stem mysticetes, including: interdental filtration, suction feeding, and baleen assisted filter feeding.”

Propose all you want to with an invalid phylogeny and you’ll end up like these two authors: confused. Add taxa to resolve all such issues.

“The description of many new taxa in rapid succession has served to muddy the waters regarding the relationships among the stemward mysticetes, in part because of the use of several different matrices which contain different taxa and codings for many characters.”

The real problem is and always has been taxon exclusion.

“The combination of these matrices into a single matrix serves as an ideal starting point for assessing the phylogenetic relationships of newly published basal mysticetes. To that end, the most recently published versions of two prominent fossil mysticete data matrices were combined.”

Brand and Uhen are “Pulling a Benton and Hone” here by making a supertree of taxa that get them no closer to understanding mysticete origins — because, like Benton and Hone’s ill-fated attempt to find pterosaur ancestors by deleting pterosaur ancestors, Brand and Uhen continue to omit pertinent taxa. Look to the LRT for your taxon list. Or build your own wide gamut cladogram. Don’t borrow. Don’t trust. Don’t build supertrees.

“The first matrix contains 106 taxa and 275 characters, while the second contains 87 taxa and 363 characters. Crown Mysticeti were coded as a limited set of operational taxonomic units, as an abundance of crown taxa were not likely to be informative of the phylogenetic relationships of stem taxa.”

The authors will never understand mysticete origins without adding desmostylians and a long list of taxa going back to tree shrews (Fig. 2).

If you want to ‘tackle the mysticete mystery’
add a few mesonychids, desmostylians, hippos, tenrecs, anagalids, etc. etc. (Fig. 2). If you do, you’ll understand mysticete origins before the present crop of whale experts, all of whom refuse to add valid outgroup taxa (Fig. 3). We’ve known this since 2016.

References
Brand NA and Uhen MD 2021. Tackling the mysicete mystery: Combining disparate matrices to examine the evolution of feeding modes in early baleen whales. Society of Vertebrate Paleontology abstracts: 64.

researchgate.net/publication/The_triple_origin_of_whales