The length of the vertebral column of primates: an allometric study.

The length of the vertebral column of 425 primates (151 prosimians, 76 platyrrhines and 198 catarrhines) was related to body mass from bibliographic sources. Regressions were calculated for the whole sample and separately for the three taxonomic groups quoted above. In parallel, the lengths of the cervical, thoracic and lumbar regions were calculated in a sample of 105 primates (30 prosimians, 19 platyrrhines and 56 catarrhines) and partial correlations established. In all cases except one, the correlation coefficients were significant. Of these, 12 correlations (out of 16) scaled with negative allometry (< 0.33), 4 with positive allometry (> 0.33), and in 6 cases the exponents were not significantly different from the criterion for isometry (0.33). The lumbar region showed the highest variability, mainly in platyrrhines and catarrhines. Results from catarrhines are globally the closest to the expectations of elastic similarity. No obvious direct relationship was found between the length of the vertebral column and the number of vertebrae.