The shell, which is a distinguishing feature of chelonians, is a remarkable structure that encloses the entire animal in a bony case with openings only at the front and rear. It is divided into an upper carapace and a lower plastron. It is a complex structure, composed of an outer horny layer covering a bone case which is fused to the rib cage. Early chelonians had teeth, but these are absent in all living forms. Instead they have horny beaks. Most chelonians are herbivorous. All lay eggs, those of aquatic forms normally being soft-shelled and those of terrestrial forms, hard-shelled. There is sometimes confusion about the common names tortoise, turtle, and terrapin. These names have no scientific meaning, and is normally only used to differentiate those species that live on land, in the sea, and in fresh water, respectively. Terrestrial chelonians usually have high domed shells and stout limbs. Aquatic ones usually have webbed feet and relatively flat shells to offer less resistance to movement in water. There are some 273 living chelonian species. The southern African subregion has a very rich chelonian fauna, with five sea turtles in coastal waters, nine terapins in freshwater rivers and vleis, and 14 land tortoises.
The tortoise species profiles were prepared by Ernst Baard (CapeNature).
Species occurring in the GCBC:
Common Padloper, Parrot-beaked Tortoise
Southern Speckled Padloper
Namaqualand Tent Tortoise
Bushmanland Tent Tortoise