Indian Star Tortoise - Anatomy and Morphology

Anatomy and Morphology

Carapace very convex, dorsal shields often forming humps; lateral margins nearly vertical; posterior margin somewhat expanded and strongly serrated; no nuchal; supracaudal undivided, incurved in the male; shields strongly striated concentrically; first vertebral longer than broad, the others broader than long, third at least as broad as the corresponding costal. Plastron large, truncated or openly notched in front, deeply notched, bifid behind; suture between the humerals much longer than that between the femorals; suture between the pectorals very short; axillary and inguinal rather small. Head moderate; forehead swollen, convex, and covered with rather small and irregular shields; beak feebly hooked, bi- or tricuspid; edge of jaws denticulated; alveolar ridge of upper jaw strong. Outer-anterior face of fore limb with numerous unequal-sized, large, imbricate, bony, pointed tubercles; heel with large, more or less spur-like tubercles; a group of large conical or subconical tubercles on the hinder side of the thigh. Carapace black, with yellow areolae from which yellow streaks radiate; these streaks usually narrow and very numerous: plastron likewise with black and yellow radiating streaks. The Indian star tortoise can grow 10 inches long.

The patterning although highly contrasting is disruptive and breaks the outline of the tortoise as it sits in the shade of grass or vegetation. They are mostly herbivorous and feed on grasses, fallen fruit, flowers and leaves of succulent plants, and will occasionally eat carrion. In captivity however they should never be fed meat.

The sexual dimorphism of adult Indian star tortoises is quite apparent. Females are considerably larger than their male counterparts. In addition, the females plastron is much flatter than that of the males which has a concave shape.

The shape of this creature is presumed to be specially adapted to naturally assist it to return to a stable stance after it has been turned over. Mathematicians Gábor Domokos of the Budapest University of Technology and Economics and Péter Várkonyi of Princeton University designed a homogenous object called Gömböc that has exactly one unstable balance point and exactly one stable balance point. Just as a bottom-weighted (non-homogenous weight distribution) sphere would always return to the same upright position, they found it was possible to construct a shape that behaves the same way. After that, they noted the similarity to the Indian Star Turtle and subsequently tested 30 turtles by turning them upside down. They found that many of them were self-righting.