Figure 6. Number of vertebrae in each of the two regions of the vertebral column, abdominal and caudal, for six clades in the museum-based study. Solid circles () represent the species means for number of abdominal vertebrae, and solid squares () represent the species means for number of caudal vertebrae. Solid regression lines are for abdominal vertebral number and dashed regression lines are for caudal vertebral number. The thick regression lines were calculated from the raw data points shown, and the thin regression lines are based on independent contrasts. Regression statistics are given in Tables 2, 3.