Extension of paleoneurological studies to the spinal cord allows functional and phylogenetic interpretations of the anatomy and locomotory patterns of fossil taxa previously thought to be inaccessible. Preliminary morphometric analysis of vertebrae of living mammalian genera indicates that the mammalian spinal cord differs from the reptilian cord in several characters with osteological ramifications. These characters can be used to recognize the appearance of mammalian spinal traits in the fossil record. A relationship between the size of segmental spinal cord cross-sectional area and locomotory mode has been demonstrated in living reptiles and used to predict limb function in extinct taxa. Measurement of a wide range of living mammalian genera will establish standards of relative spinal cord size for different locomotory patterns. Comparison of these values to those obtained from fossil taxa will allow reconstruction of the adoption of different patterns of limb use in a variety of mammalian orders. Osteological specimens of living and fossil genera will be studied in a small number of rich museum collections using computer-based imaging.
