Chelonoidis niger chathamensis

Chelonoidis niger chathamensis, commonly known as the Chatham Island giant tortoise or the San Cristóbal giant tortoise, is a subspecies of Galápagos tortoise endemic to San Cristóbal Island in the Galápagos.[1]

San Cristóbal giant tortoise
CITES Appendix I (CITES)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Testudinoidea
Family: Testudinidae
Genus: Chelonoidis
Species:
Subspecies:
C. n. chathamensis
Trinomial name
Chelonoidis niger chathamensis
Synonyms
  • Testudo chathamensis Van Denburgh, 1907
  • Geochelone nigra chathamensis (Van Denburgh, 1907)

Population history edit

The subspecies was heavily exploited and eliminated over much of its original range. Trampling of nests by feral donkeys, and the predation of hatchlings by feral dogs decimated populations, but the breeding program has led to successful releases.

Fencing of nests and dog eradication in the 1970s helped in the population recovery.[4]

Their population is thought to have dropped to as low as 500-700 individuals in the 1970s, and was around 24,000 prior to human contact. In a census conducted in November 2016, the population was found to be making a rapid recovery. A total of around 6,700 individuals were found, with around 2,700 mature adults and 3,750 juveniles.[1]

Breeding centers such as the Galapaguera of Cerro Colorado were established in order to encourage captive reproduction of the endangered Galapagos tortoise. They were then released in their areas of origin to recover the wild populations.[5]

Description edit

It has a wide, black shell, its shape intermediate between the saddle-backed and domed subspecies: adult males are rather saddle-backed, 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.[6]

References edit

  1. ^ a b c Caccone, A.; Cayot, L.J.; Gibbs, J.P.; Tapia, W. (2017). "Chelonoidis chathamensis". IUCN Red List of Threatened Species. 2017: e.T9019A82688009. doi:10.2305/IUCN.UK.2017-3.RLTS.T9019A82688009.en. Retrieved 19 November 2021.
  2. ^ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. ^ Van Denburgh, John (1907). "Preliminary descriptions of four new races of gigantic land tortoises from the Galapagos Islands". Proceedings of the California Academy of Sciences. 4th series. 1: 1–6.
  4. ^ Cayot 1994. Conservation biology of Galápagos reptiles: twenty-five years of successful research and management. In: J. B. Murphy, K. Adler, and J. T. Collins (eds.). Captive Management and Conservation of Amphibians and Reptiles, pp. 297–305. Ithaca, New York: Society for the Study of Amphibians and Reptiles. Contributions to Herpetology. vol. 11. ISBN 0-916984-33-8.
  5. ^ Cerreta, Anthony J.; Vaden, Shelly L.; Lewbart, Gregory A.; Muñoz-Pérez, Juan Pablo; Páez-Rosas, Diego (June 2019). "Increased BUN and glucose in a group of San Cristóbal galapagos tortoises ( Chelonoidis chathamensis )". Veterinary Record Case Reports. 7 (2). doi:10.1136/vetreccr-2018-000699. ISSN 2052-6121. S2CID 155124068.
  6. ^ Pritchard (1979), Encyclopedia of turtles, Neptune, New Jersey: T. F. H. Publ., Inc.
  • Van Denburgh, 1907 : Expedition of the California Academy of Sciences to the Galapagos Islands, 1905–1906. I. Preliminary descriptions of four new races of gigantic land tortoises from the Galapagos Islands. Proceedings of the California Academy of Sciences, ser. 4, vol. 1, p. 1–6 (Full text).