A subantarctic reigitheriid and the evolution of crushing teeth in these enigmatic Mesozoic mammals

Mesozoic mammals from Gondwana remain poorly understood, with most species known only from isolated teeth. Nevertheless, these tantalizing fossils point to a diversity of families, that were distinct from Laurasian forms. Among these, the enigmatic South American family Reigitheriidae, was proposed based on the unique crushing teeth of its sole representative, Reigitherium from Northern Patagonia. Here, we report a new mammal, Yeutherium pressor gen. et sp. nov., which is only the second known taxon of Reigitheriidae. This is based on a partial maxilla bearing an upper molar from the Late Cretaceous Dorotea Formation in the Río de Las Chinas Valley, Sub-Antarctic Chile. Parsimony and Bayesian phylogenetic analyses indicate a close relationship between Reigitherium and Yeutherium. Shared features between both taxa—such as expanded pre- and postparacristae, a lingual cingulum at the paracone base, interradicular crests, and enamel crenulations—help define Reigitheriidae. Cingula developme..., , # A subantarctic reigitheriid and the evolution of crushing teeth in these enigmatic Mesozoic mammals

Dataset DOI: [10.5061/dryad.0gb5mkmdb](10.5061/dryad.0gb5mkmdb)

## Description of the data and file structure

Data associated with the article **'A subantarctic reigitheriid and the evolution of crushing teeth in these enigmatic Mesozoic mammals'** from Püschel et al. 2025. It contains the following 4 files: 

**1)  ESM-2-CT-movie-Yeutherium-rotation-1.mp4:** Contains a CT-movie of the holotype of Yeutherium rotating in one direction.

**2) ESM-3-CT-movie-Yeutherium-rotation-2.mp4:** Contains a CT-movie of the holotype of Yeutherium rotating in one direction.

**3) Yeutherium_matrix-TNT-command-innaplicable-characters.tnt**: It is a .tnt file to be run in the TNT software with the matrix and the commands for considering inapplicable characters in the parsimony phylogenetic analyses.

**4) Yeutherium_matrix_MrBayes-commands.nex:** It is a Nexus file to be run in MrBayes with the matri...,