SVP 2021 abstracts – 11: Evolution of dentition in Mammaliamorpha

Mammaliamorpha definition:
“The most recent common ancestor of Morganucodonta and the crown group mammals.”

Since Morganucodon (Fig. 1) is a basal marsupial in the large reptile tree (LRT, 1989+ taxa, subset Fig. 2). So Mammaliamorpha is a junior synonym for Mammalia.
Mammaliamorpha may be a junior synonym for Probainognathia (Martinez et al. 1996).
The definition depends on the taxon list and cladogram.

So when Sulej 2021 reports on “The evolution of dentition in Mammaliamorpha”, he’s actually talking about just Mammalia. If Sulej brings up any outgroups (Fig. 2), those should be beyond the scope of his study based on his headline.

In the LRT (subset Fig. 1) Brasilitherium is not related to Brasilodon.
Only two of the above taxa are related to one another.

Suggestion: Build your own cladogram.
Don’t depend on (= trust) “recent phylogenetic anlyses”.

Mammals are defined by breast feeding. That is inferred in fossils by single replacement teeth (= diphyodonty) in which milk teeth first erupt as breast feeding ceases.

“However, we still do not know the sequence of the appearance of the apomorphies leading to the dentition of Morganucodon, such as double rooted teeth, multicuspidated lingual cingulum shelf, and diphyodont dentition.”

Sulej would know the sequence of the appearance of any and every trait if he had a valid phylogenetic framework, like the LRT. Build your own cladogram. Don’t borrow.

References
Martinez RN, May CL and Forster CA 1996. A new carnivorous cynodont from the Ischigualasto Formation (Late Triassic, Argentina), with comments on eucynodont phylogeny. Journal of Vertebrate Paleontology 16(2):271-284.
Sulej T 2021. Evolution of dentition in Mammaliamorpha. Journal of Vertebrate Paleontology abstracts.