Lower jaw of the morganucodontid Morganucodon with manually edited middle ear bones, based on illustrations in Kermack et al. (1973), Kermack et al. (1981) and Luo (2011). Depicted in color code are the following elements: yellow = Meckel’s cartilage, dark blue = ectotympanic, green = articular, white = surangular, beige = dentary.

Specimen was scanned at the University of Texas High-Resolution X-ray CT facility using the NSI scanner. For scanning the following parameters were used: Morganucodon was scanned using the Xradia setup, 60 kV, 10 W, 1 s acquisition time, 1 mm SiO2 filter, with a voxel size of 19.64 µm.

The 3D model of the lower jaw was segmented manually from CT scans using Avizo 8.1. (Visualization Sciences Group). The 3D models of the middle ear bones and Meckel’s cartilages were manually created using MAYA 16 (Autodesk) based on illustrations in Kermack et al. (1973), Kermack et al. (1981), Luo (2011), Luo et al. (2007), Luo et al. (2016), Ji et al. (2009), and Mao et al. (2020). 

For all models, fine tune editing and virtual alignment was performed using Polyworks (2014, InnovMetric Software Inc.) including Gouraud filters for smoothing surfaces, adding and removing triangles, reworking mesh and reducing data size.