Christmas Island forest skink

Christmas Island forest skink
1900 monograph of three Christmas Island reptiles, with the forest skink at centre.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Sauria
Infraorder: Scincomorpha
Family: Scincidae
Subfamily: Lygosominae
Genus: Emoia
Species: E. nativitatis
Binomial name
Emoia nativitatis
(Boulenger, 1887)
Synonyms

Lygosoma nativitatis Boulenger, 1887[1]

The Christmas Island forest skink (Emoia nativitatis), also known as the Christmas Island whiptail skink, is a species of skink endemic to Australia's Christmas Island.[2] Although listed as Critically Endangered on the IUCN Red List[1] and under the EPBC Act,[3] it is considered by many to be extinct.[4][5] The last known forest skink, a captive individual named Gump, died on 31 May 2014.[4]

Description

The Emoia skinks, of which the Christmas Island forest skink is the most ancestral member, are a large group with marked radiation on islands in the Pacific.[6] The forest skink is about 20 cm long, thickset, ground-dwelling, and active during the day.[6] Its body is a chocolate-brown colour and unpatterned.[6] The species was found in forest clearings, usually in leaf litter.[1]

Discovery

The Christmas Island forest skink was described by George Albert Boulenger in 1887 based on a single tailless specimen.[7] Subsequently, eight specimens were collected by naturalist Joseph Jackson Lister.[7]

Decline and possible extinction

The Christmas Island forest skink was common and widespread on Christmas Island during most of the twentieth century. It was considered abundant in 1979.[8] As recently at 1998, herpetologist Hal Cogger observed more than 80 forest skinks basking and foraging around a single fallen tree.[6] However, populations plummeted during the 1990s and 2000s by up to 98%.[1] In 2003, the species was limited to fragmented pockets in remote parts of the island, and a targeted survey in 2008 found the species at only a single site.[6]

The cause of the species' rapid decline is still unknown,[6] although possibilities include predation by yellow crazy ants, giant centipedes, wolf snakes, and cats;[6][9] competition with five introduced reptile species; poisoning from insecticides; and disease.[6]

In the late 2000s, Christmas Island researchers tried to capture forest skinks for a captive breeding program, but only three females were ever found.[10] On 3 January 2014, the species was added to the EPBC Act List of Threatened Fauna.[3] The last surviving captive female was nicknamed Gump, and she died on 31 May 2014.[4]

Following Gump's death, herpetologists John Woinarski and Hal Cogger wrote that: "For the Forest Skink, the trajectory of decline and the fruitlessness of dedicated searches provide reasonable grounds to presume extinction, although this conclusion may take some years to be officially recognised."[4] If true, this would represent Australia's first reptile extinction since European colonisation.[4]

See also

References

  1. 1 2 3 4 Cogger, H.G. & Austin, C.C. Emoia nativitatis IUCN Red List of Threatened Species (2010). Retrieved 6 December 2015.
  2. ↑ Emoia nativitatis at the Reptarium.cz Reptile Database. Accessed 7 January 2016.
  3. 1 2 Emoia nativitatis — Christmas Island Forest Skink, Christmas Island Whiptail-skink Australian Government - Department of the Environment. Retrieved 6 December 2015.
  4. 1 2 3 4 5 John Woinarski, Don Driscoll and Hal Cogger, "Vale ‘Gump’, the last known Christmas Island Forest Skink", The Conversation, 8 August 2014. Retrieved 6 December 2015.
  5. ↑ Bettina Arrow, "Researchers work to save endangered reptiles on Christmas Island" ABC News, 18 November 2014. Retrieved 26 December 2015.
  6. 1 2 3 4 5 6 7 8 John Woinarski and Hal Cogger, Australian endangered species: Christmas Island Forest Skink, The Conversation, 19 September 2013. Retrieved 26 December 2015.
  7. 1 2 Boulenger GA (1888) "On the Reptiles of Christmas Island" Proc. Zool. Soc. London: 534-536.
  8. ↑ Smith MJ, Cogger H, Tiernan B, Maple D, Boland C, Napier F, Detto T, & Smith P (2012) "An Oceanic island reptile community under threat: The decline of reptiles on Christmas Island, Indian Ocean" Herpetological Conservation and Biology, 7(2): 206–218. Retrieved 26 December 2015.
  9. ↑ Dave Algar, Neil Hamilton & Caitlyn Pink, "Progress in eradicating cats (Felis catus) on Christmas Island to conserve biodiversity" Raffles Bulletin of Zoology, Supplement No. 30: 45–53 (25 December 2014). Retrieved 26 December 2015.
  10. ↑ "A Science Story: Saving Christmas" Lateral magazine, 21 December 2015. Retrieved 26 December 2015.
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