Embryonic Development and Histological Analysis of Skeletal Muscles of Tenuidactylus caspius (Eichwald, 1831) Lizards (Reptilia: Squamata)

Abstract

During embryonic development of the Caspian thin-toed gecko migration, formation of myoblast and myosatellite cells occurs in the cranial-distal direction. Somite formation begins in the body part close to the skull and ends in the tail. The time of separation of somites from the proximal mesoderm depends on the temperature of the air and the substrate. Myoblast cells reach their targets and are connected, and the membranes in the area of their contact are destroyed. Myoblast’s fusion creates myosymplasts. The intermediate stage is observed after the formation of small myosymplasts. After that, the chain shape of myosymplasts are transformed into an intermediate plaque form. At this intermediate stage, the number of a nucleus is small, the shape of the nucleus differs from each other, and the location of the nucleus varies. Afterward, the connection of the intermediate forms with each other and with myoblasts forms a rounded shape, where the initial development of myotubules takes place. A fully formed myotubular and myosatellite cells are surrounded by a basal membrane and shape a muscle fiber. The skeletal muscles of the adult Caspian thin-toed gecko are mainly composed of white fibers. Thus, it allows the gecko to move very fast in a short time. Due to the small number of mitochondria in the myotubes, oxygen gas demand is decreased and the body is prevented from overheating.