It is widely accepted that the population living on the most northern volcano, Volcan Wolf, is genetically independent from the four other southern populations and is therefore its own subspecies.
The five populations living on the largest island, Isabela, are the ones that are the subject of most debate as to whether they are true subspecies or just distinct populations. Modern DNA methods have revealed new information on the relationships between the subspecies: Charles Darwin's observations of these differences on the second voyage of the "Beagle" in 1835, contributed to the development of his theory of evolution. On islands with humid highlands, the tortoises are larger, with domed shells and short necks - on islands with dry lowlands, the tortoises are smaller, with "saddleback" shells and long necks. Shell size and shape vary between populations. The front legs have five claws, the back legs four.
#La pinta island tortoise skin
The legs are large and stumpy, with dry scaly skin and hard scales. A tortoise can withdraw its head, neck and forelimbs into its shell for protection. Tortoises keep a characteristic scute pattern on their shell throughout life, though the annual growth bands are not useful for determining age because the outer layers are worn off with time. Lichens can grow on the shells of these slow-moving animals. The plates of the shell are fused with the ribs in a rigid protective structure that is integral to the skeleton. The tortoises have a large bony carapace of a dull brown colour.
0 kommentar(er)
