Results of Multiple Correspondence Analysis (MCA). Squares represent closely associated character states of the vertebral column with the analyzed species. The numeric suffixes in the active variables represent the actual number of vertebrae (the character state). Abbreviations: T – total vertebrae, A – abdominal vertebrae, C – caudal vertebrae, a1 – predorsal vertebrae, i – intermediate vertebrae, c1 – preanal vertebrae, c2 – postanal vertebrae.