The caudal vertebrae have tall, straight neural spines that lack any processes or zygosphene-zygantrum articulation, a joint found in most squamates. The caudal vertebrae have a small, triangular-shaped neural tube. The centrum is shortened on the rostro-caudal side but is elongated dorso-ventrally and compressed laterally, resulting in a ventrally oval rather than circular condyle as seen in presacral vertebrae. The caudal vertebrae of Taniwhasaurus have craniocaudal centra not fused to the hemal arch, which is a typical case in tylosaurines. Hemal arches articulate with deep hemapophyses but do not fuse with them. Distally, the right and left halves merge midway from the ventral tip of the element, creating a large anterior ridge on the vertebral column.
