Cranial anatomy and phylogenetic affinities of Bolosaurus major, with new information on the unique bolosaurid feeding apparatus and evolution of the impedance-matching ear

Resolving the phylogenetic relationships of early amniotes, in particular stem reptiles, remains a difficult problem. Three-dimensional morphological analysis of well-preserved stem-reptile specimens can reveal important anatomical data and clarify regions of phylogeny. Here, we present the first thorough description of the unusual early Permian stem reptile Bolosaurus major, including the first comprehensive description of a bolosaurid braincase. We describe previously obscured details of the palate, allowing for insight into bolosaurid feeding mechanics. Aspects of the rostrum, palate, mandible, and neurocranium suggest that B. major had a particularly strong bite. We furthermore found B. major has a surprisingly slender stapes, similar to that of the middle Permian stem reptile Macroleter poezicus, which may suggest enhanced hearing abilities compared to other Paleozoic amniotes (e.g., captorhinids). We incorporated our new anatomical information into a large phylogenetic matrix (150..., Two datasets were analyzed using phylogenetic methods (i.e., parsimony and Bayesian). See publication for more specific methods, citation below:
K.M. Jenkins, W. Foster, J.G. Napoli, D.L. Meyer, G.S. Bever, B-A.S. Bhullar. In Review. Cranial anatomy and phylogenetic affinities of Bolosaurus major, with new information on the unique bolosaurid feeding apparatus and evolution of the impedance-matching ear. The Anatomical Record. DOI: https://doi.org/10.1002/ar.25546
1) The first dataset analyzed is an original taxon-character matrix (select \"Download full dataset\" to view). Supplemental to this are two additional files (1) an illustrated character list (\"StemReptile_Megamatrix_IllustratedCharacterList_2024\"), and (2) the list of taxa scored (\"Taxa_Examined_2024\"). The trees produced from this dataset include parsimony (\"All_Parsimony_tre_files\") and Bayesian (\"Bayes_150_FBD\") results. The input file for the Bayesian trees is \"Full_Matrix_Bayes_150.nex\".
2) The second dataset is a smaller,..., , # Cranial anatomy and phylogenetic affinities of Bolosaurus major, with new information on the unique bolosaurid feeding apparatus and evolution of the impedance-matching ear

[https://doi.org/10.5061/dryad.q83bk3jqm](https://doi.org/10.5061/dryad.q83bk3jqm)

Included are supplemental files used for this work. It includes:

1. Word Document with table of all taxa included in the phylogenetic analyses and their sources.
2. Word Document with all characters used in phylogenetic analyses. Their states are fully illustrated, and sources from which characters are compiled are listed at the top of the document.
3. Mesquite File - This is an original mesquite file constructed for this work to produce a taxon-character matrix which corresponds to the Character List and Taxa List provided in 1 & 2 (i.e., \"StemReptile_MegaMatrix_Mesquite_2024_April\"). This matrix was analyzed in both parismony and Bayesian frameworks. See publication for more detailed phylogenetic methods.
4. A folder of all ...