Tail Fracture Planes of Autotomy in Geckos

Abstract

The structure of the tail facture planes was morphologically and histologically studied in two species of geckoid lizards, living in Qatar, Cyrtodactylus scaber and Bunopus tuberculatus. The fracture plane is formed of a vertebral split, connective tissue septum in the fat zone surrounding the vertebrae and the myoseptum separting the adjacent muscle segments. The split passes through the middle of each vertebra. All the caudal vertebrae, except for the first five, possess such autotomy separations. The notochord which passes through the centrum is replaced by notobhordal cartilage or septum at the autotomy plane. The contraction of the numerous muscle attachments near the autotomy plane leads to the breaking of the vertebra. All the caudal vertebrae, except for the first four, have Y-shaped chevron bones.