Fig. 1

a–b Examples of two salamander species: the Northern red salamander (Pseudotriton ruber) and smooth newt (Triturus vulgaris). Most salamander species are between 10 and 20 cm in length [38]. c Role of muscle fiber cellularization in limb regeneration. After catastrophic limb injury, such as amputation, a wound epithelium is formed. Skeletal muscle fibers beneath the epithelium lose contact with each other and contract. Apoptotic signaling is initiated and the fiber undergo cellularization, which involves cell cycle re-entry and dedifferentiation. The proliferating mononuclear cells contribute to a zone of proliferating cells termed the blastema, which will form the tissues of the replacement limb. Cellularized skeletal muscle fibers retain memory of their tissue origin and re-differentiate into skeletal muscle in the new limb