Didelphis virginiana (the Virginia opossum) is often used as an extant model for understanding feeding behavior in Mesozoic mammaliaforms, primarily due to their morphological similarities, including an unfused mandibular symphysis and tribosphenic molars. However, the 3D jaw kinematics of opossum chewing have not yet been fully quantified. We used biplanar videofluoroscopy and the X-Ray Reconstruction of Moving Morphology workflow to quantify mandibular kinematics in four wild-caught opossums feeding on hard (almonds) and soft (cheese cubes) foods. These data were used to test hypotheses regarding the importance of roll versus yaw in chewing by early mammals, and the impact of food material properties (FMPs) on jaw kinematics. The magnitude of roll exceeds that of yaw, but both are necessary for tooth-tooth or tooth-food-tooth contact between complex occlusal surfaces. We confirmed the utility of the four vertical kinematic gape cycle phases identified in tetrapods but we further defined two more in order to capture non-vertical kinematics. Statistical tests support the separation of chew cycle phases into two functional groups: occlusal and non-occlusal phases. The separation of slow close into two (occlusal) phases gives quantitative kinematic support for the long-hypothesized multifunctionality of the tribosphenic molar.

The raw data for this study is saved here as CSV files exported from the first left and right lower molars (talonid basins) of all individuals in this study relative to a midline axis. The data is of individual chewing sequences, with individual and food type indicated in the file name.

Data analysis code is written for Matlab (.m files).

The supplementary data document contains a table with the coordinate data for the midline reference axis and first molars. 

All data analysis code was made in Matlab. However, the files can be opened in any text editor. The methods and workflow for the analysis are extensively explained in the comments.