Western Santa Cruz tortoise

The western Santa Cruz tortoise (Chelonoidis niger porteri)^[1] is a subspecies of Galápagos tortoise endemic to Santa Cruz Island in the Galápagos. They are found only on the southwestern slopes of the island, with an estimated range of 141 sq. kilometers. There are approximately 3400 individuals in the wild, and have seen rising numbers in population, despite being critically endangered. MtDNA evidence shows that there are actually three genetically distinct populations on Santa Cruz Island. They are characterised by a black, oval carapace (to 130 cm) that is domed, higher in the centre than in the front, and broad anteriorly. Their life expectancy is 175 years.^[3]

Map of the Galápagos Islands showing locations of different tortoise species

Western Santa Cruz tortoise
Conservation status
Critically Endangered  (IUCN 3.1)[1]
CITES Appendix I (CITES)[2]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Superfamily:	Testudinoidea
Family:	Testudinidae
Genus:	Chelonoidis
Species:	C. niger
Subspecies:	C. n. porteri
Trinomial name
Chelonoidis niger porteri (Rothschild, 1903)
range on coastal slopes of La Reserva
Synonyms
Testudo porteri Rothschild, 1903 Geochelone nigra porteri (Rothschild, 1903)

In 2015, the small, eastern Cerro Fatal population of the island was described as a distinct subspecies, C. n. donfaustoi, most closely related to chathamensis (and forming a clade with it plus abingdoni and hoodensis), while the main southwestern porteri population was found to be closer to the Floreana and southern Isabela tortoises.^[4][5]

References

1. Cayot, L.J.; Gibbs, J.P.; Tapia, W.; Caccone, A. (2017). "Chelonoidis porteri". IUCN Red List of Threatened Species. 2017: e.T9026A82777132. doi:10.2305/IUCN.UK.2017-3.RLTS.T9026A82777132.en. Retrieved 19 November 2021.
2. "Appendices | CITES". cites.org. Retrieved 2022-01-14.
3. Thomson, Scott; Irwin, Steve; Irwin, Terri (March 1998). "Harriet, The Galapagos Tortoise. Disclosing One and a Half Centuries of History". Reptilia. 2: 48–51.
4. Marris, E. (2015-10-21). "Genetics probe identifies new Galapagos tortoise species". Nature. doi:10.1038/nature.2015.18611. S2CID 182351587. Retrieved 2015-10-23.
5. Poulakakis, N.; Edwards, D. L.; Chiari, Y.; Garrick, R. C.; Russello, M. A.; Benavides, E.; Watkins-Colwell, G. J.; Glaberman, S.; Tapia, W.; Gibbs, J. P.; Cayot, L. J.; Caccone, A. (2015-10-21). "Description of a New Galapagos Giant Tortoise Species (Chelonoidis; Testudines: Testudinidae) from Cerro Fatal on Santa Cruz Island". PLOS ONE. 10 (10): e0138779. Bibcode:2015PLoSO..1038779P. doi:10.1371/journal.pone.0138779. PMC 4619298. PMID 26488886.