Charles Island, Galapagos
|Population and range
(from Abingdon Island)
Abingdon Island tortoise
|Günther 1877. The holotype of C. n. ephippium (Günther 1875) is a misidentified C. n. abingdoni, so technically abingdoni is a junior synonym.
|Lonesome George, the last living member, died June 2012. This subspecies was severely depleted by whalers and fishermen, and the introduction of goats in 1958 resulted in massive destruction of vegetation. The carapace is shaped like a saddle, very narrow, compressed, and slightly upturned anteriorly, and wider and lower posteriorly with a rounded margin.
|No known individuals. Formerly the southern slopes of Pinta (Abingdon) island, now extinct. In 2007, a Pinta hybrid was found on Isabela Island, suggesting that there may be an Abingdon tortoise in the wild.
C. n. becki (named for Rollo Beck)
|Reproduction is successful. Apparently two morphotypes occur on Volcan Wolf, domed and saddle-backed. A more flattened or dome-shelled population from the south may have crossed the former lava barrier and mixed with an isolated population of saddlebacked tortoises. For the saddlebacked variety, the gray, carapace is relatively thick with little or no cervical indentation, the anterior carapacial rim upturned, and the posterior marginals flared and slightly serrated. The carapace is compressed or narrowed anteriorly, but not nearly as much as some other saddlebacked subspecies.
&&&&&&1, 139 individuals. Northern Isabela (Albermarle) Island, northern and western slopes of Volcano Wolf.
Recent research indicates that the variation is caused by hybridization of native Isabela tortoises with about 40 descendents of tortoises from Floreana, a population thought to be extinct since the 1850s.
C. n. chathamensis (from Chatham Island)
Chatham Island tortoise
|Van Denburgh 1907
|Heavily exploited and completely eliminated over much of its original range. Trampling of nests by feral donkeys, and the predation of young by feral dogs decimated populations, but the breeding program had led to successful releases. It has a wide, black shell, its shape intermediate between the saddlebacked and domed species: adult males are rather saddlebacked, but females and young males are wider in the middle and more domed. A now extinct, more flat-shelled form occurred throughout the wetter and higher regions of the island most altered by man when the island was colonized. The type specimen was from this extinct population, so it is possible that the subspecies currently designated C. n. chathamensis is mistakenly applied.
|&&&&&&1, 824 individuals. San Cristóbal (Chatham) island, confined to the northeast. Fencing of nests and dog eradication in the 1970s helped population recovery.
C. n. darwini (named for Charles Darwin)
|Large numbers of tortoises were removed from the island in the early nineteenth century by whaling vessels, and introduced goats reduced the coastal lowlands to deserts, restricting the remaining tortoises to the interior. The sex ratio is strongly imbalanced in favour of the males and most nests and young are destroyed by feral pigs. Some nests are now protected by lava corrals and since 1970 eggs have been transported to the Charles Darwin Research Station for hatching and rearing. Release programs and measures for nest protection from feral pigs have been successful. The gray to black carapace is intermediate in shape between the saddlebacked species and those with domed shells. It has only a shallow cervical indentation; the anterior carapacial rim is not appreciably upturned, and the posterior marginals are flared, slightly upturned, and slightly serrated.
|&&&&&&1, 165 individuals though a strong male bias in the remaining population impedes a quick recovery of the population. Santiago (James) Island, west-central areas.
|C. n. duncanensis (from Duncan Island)