Fig. 3

Shape variation in the extant penultimate thoracic vertebrae captured by PCs 1 and 3, which account for 19.7 and 7.3% of the variation, respectively. PC2 did not did not reveal differences among the taxa and therefore was replaced with PC3. The wireframes illustrate the vertebral shapes described by PC1 and PC3. The stars indicate where the wireframes are located in the scatter-plot