Turtle shell is characterized by a high degree of conservatism of the basic model and at the same time, a wide range of variability at the individual level. The components of the bony shell have different origin. Costal and neural plates are upgraded elements of the axial skeleton (ribs and neural arches), plates of the plastron are transformed dermal ossiications of the shoulder girdle and gastral bones, peripheral, pygal and suprapygal plates naturally similar to osteoderms of other reptiles. The variability of the bony parts has different expressions in turtle shell. The largest number of anomalies detected in the caudal portion of the carapace. Plastron is characterized by morphological stability. Based on morphogenetic position shell anomalies are divided into: 1) variations due to the variability of the axial skeleton elements or their contacts with the dermis inside which they grow (number of neural and costal plates); 2) variations due to variability i