Question

The shell of a turtle or tortoise is divided into an upper and a lower section. What is the lower section called?

• A. Plastron
• B. Scute
• C. Carapace
• D. Subshell

Answer 1

The correct option is A Plastron

The turtle shell is a highly complicated shield for the ventral and dorsal parts of turtles, tortoises and terrapins (all classified as "turtles" by zoologists), completely enclosing all the vital organs of the turtle and in some cases even the head. It is constructed of modified bony elements such as the ribs, parts of the pelvis and other bones found in most reptiles. The bone of the shell consists of both skeletal and dermal bone, showing that the complete enclosure of the shell probably evolved by including dermal armor into the rib cage. The plastron is the nearly flat part of the shell structure of a turtle, what one would call the belly or ventral surface of the shell. It also includes within its structure the anterior and posterior bridge struts and the bridge of the shell. The plastron is made up of nine bones and the two epiplastra at the anterior border of the plastron are homologous to the clavicles of other tetrapods. The rest of the plastral bones are homologous to the abdominal ribs of other tetrapods.

So the correct option is 'plastron'.