Maximal caudal autotomy in Podarcis hispanica (Lacertidae): The caudofemoralis muscle is not sundered

In recent years, the pattern of maximal caudal autotomy in lizards has come under consideration, with attention being focused on how nonsegmental musc les in the tail base, specifically the m. caudofemoralis longus and the m. retractor penis magnus, may limit autotomy where they cross autotomy planes or, alternatively, how they may be ruptured if maximal autotomy is practic ed. In this paper, we demonstrate that in the lacertid lizard Podarcis hisp anica a number of autotomic vertebrae are spanned by the m. caudofemoralis longus, that maximal caudal autotomy does occur, and that the caudofemorali s muscle dissociates from its vertebral attachments but is not torn in the process. Anatomical and histological data reveal that this muscle has a spe cialized structure and relationship with surrounding muscles, skeletal elem ents, and connective tissues that result in minimal damage upon maximal aut otomy. Furthermore, upon caudal regeneration, the m, caudofemoralis longus reestablishes contact with the newly formed cartilaginous axial skeleton of the tail.