Extreme neck elongation in Triassic tanystrophes

Triassic Tanystropheus was characterised by the most elongate vertebrae among the known animals. Elongation of the vertebrae of Tanystropheus was a result of developmental constraints – difficulties in increasing the number of presacral vertebrae. The latest research shows that the development of the long-neck in these reptiles proceeded differently than in, e.g., dinosaurs, in which new vertebrae appeared in the posterior part of the neck. In Tanystropheus the maximisation of the neck elongation occurred by “shifting” the dorsal vertebrae into the cervical region and incorporating them into the anterior morphological module that included the longest vertebrae.