Jewelled gecko

For the Australian species called jewelled gecko, see Strophurus elderi

Jewelled gecko
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Reptilia
Order:Squamata
Family:Diplodactylidae
Genus:Naultinus
Species: N. gemmeus
Binomial name
Naultinus gemmeus
(McCann, 1955)
Synonyms

Naultinus lineatus Gray, 1869 Naultinus elegans Lucas and Frost, 1897
Naulthinus elegans Werner, 1901
Heteropholis gemmeus McCann, 1955
Heteropholis gemmeus Wermuth, 1965
Naultinus elegans gemmeus Meads, 1982
Naultinus gemmeus Thomas, 1982
Naultinus gemmeus Rösler, 2000

The jewelled gecko (Naultinus gemmeus) is a species of gecko endemic to the South Island of New Zealand.

Introduction

There are two main subgroups of jewelled geckos: those living in Otago and those living in Canterbury. There is also a small Southland population. One obvious difference is that some of the males of the Canterbury geckos are grey or brown with yellow, purple and white markings; whereas all Otago geckos are green with yellow and white markings. The Southland population are solid green.

Their diet mainly consists of insects and moths, but they also enjoy berries of certain plants, and the nectar of certain flowers.

These and other New Zealand geckos are highly protected and it is illegal to capture or disturb them. Jewelled geckos are often targeted by wildlife smugglers.[2]

Identification

Naultinus gemmeus has a bright to olive green body with either rows of stripes going down its back or a diamond shape pattern running down the back according to the New Zealand Department of Conservation. This jewelled or diamond shaped pattern is where the species got its common name, and is an important identifying feature. The colors that are often seen in the stripes or diamond shapes are white, pale green, or yellow and those colors are often outlined by black or dark brown.[3] Their underbelly is usually a pale greenish yellow or gray and can sometimes have stripes or streaks too. There appear to be some differences in looks between the Otago and Canterbury subgroups of Jewelled gecko, as well as between the male and females.[4][4] For both the Otago and Canterbury subgroups it seems that the females are more likely to have a jewelled pattern, while the males have stripes or no pattern. For the Otago subgroup the mouth of the jewelled gecko typically has a lining of deep blue color and a blackish tongue, whilst the Canterbury subgroup have a mouth lining of pinkish color and a pink or orange tongue.[4][4] Their eye color ranges from brown to olive colored.[3] These geckos can get to a total length of 18 cm [5] with the body measuring about 60 to 80mm from snout tip to anus.[3] It can also weigh up to 15 grams and has a very long life span lasting at least 40 years.[5]

Conservation status

Naultinus gemmeus on a branch, Otago Peninsula by Rod Morris

In 2012 the Department of Conservation reclassified the jewelled gecko as At Risk under the New Zealand Threat Classification System. It was judged as meeting the criteria for At Risk threat status as a result of it having a low to high ongoing or predicted decline.[6] Jewelled geckos has a status of near threatened on the IUCN redlist, caused by several threats such as habitat destruction, degrading and fragmenting through grazing, herbicides and burning, as well as introduced predators.[1]

Geographic Distribution

Jewelled gecko is a native species to the South Island of New Zealand. It is found only on the southeast of the South Island, more precisely in Canterbury and Otago whereas the main populations are found. Other populations have been found in the area in between Canterbury and Otago, but the populations as well as the habitats are small, isolated and fragmented. The species has undergone a decline in population the recent years, and is now considered near threatened by the IUCN.[7]

Habitat

The preferred habitat for Jewelled gecko is diverse woody vegetation, drylands and shrublands. It needs shelter from cold and fires in the landscape, and is therefore dependent on woody forest vegetation. Jewelled gecko is also an arboreal, diurnal species, which means it lives in trees and is active during the day.[7] It can live in a wide range of tree- and shrub species, like manuka, beech and matagouri.[1] Rocky outcrops and boulder fields also can be suitable habitat for easy escapes from predators.[7]

Lifecycle

Female jewelled geckos are viviparous and typically give birth in autumn, usually a little earlier for Canterbury individuals than the Otago ones.[8] Reproduction happens annually, and pregnancy lasts about seven months.[9] The reproductive cycle of Jewelled gecko consists of vitellogenesis, ovulation and pregnancy, whereas vitellogenesis starts in autumn after birth and ovulation happens during spring. Each female give birth to one or two juveniles.[9]

The Naultinus gemmeus (Jewelled gecko) lifespan is unknown, however, it is thought to live over 30 years old when predation and habitat fragmentation aren’t an issue, based on the lifespan of other gecko species in the area.[5] Although most geckos endemic to New Zealand are slow growing and can take 2–8 years to reach maturity the Jewelled gecko takes 4 years to reach maturity. Once reaching maturity it gives birth to one to two young each year and like other endemic New Zealand geckos, they give birth to live young and don’t lay eggs.[5][10] Research has shown that there is clear seasonal pattern of reproductive activity, Ovulation starting in the spring and the gestation period lasts around 7 months ending with the birth of one to two young.[3] It has been recorded in captive environments that the Jewelled gecko mating time is some time between September and October and the birth time is February to May.[11] This species bask in the sun on top of foliage on especially on warm sunny mornings and do this year round. It has been shown that pregnant females are the easiest to find and this is most likely due to needing the sun more to help development of young.[3]

Diet/Prey/Predators

Diet and foraging

The Jewelled geck along with other geckos have a rich diet of insects and berries that come from their habitat of native forest and shrublands [5] All New Zealand geckos like the Jewelled gecko are omnivores and eat a wide variety of insects such as moths and different types of flies and they also feed on berries from native plants such as the Coprosma. The New Zealand geckos have also been known to feed on the nectar of flowers when available.[12]

Predators, Parasites, and Diseases

There are many threats that the Jewelled gecko faces from farmland grazing, habitat destruction, predators, and illegal poaching. These geckos are protected under the Wildlife act of 1953, but their habitats are still being destroyed by either fragmentation by roads and invasive species.[5] The predators that these geckos face range from humans, rodents, mustelids, cats, birds, and possums. The human factor is all the illegal poaching that is going on in the predator proof areas and natural areas. Rodents, rats, are a large predator for Jewelled gecko by climbing the branches of the shrubland and forest and infiltrate their habitat. However there is evidence to show that mustelids and cats are not a main predator because they are mainly nocturnal in their hunting behavior. Birds in New Zealand, particularly the magpie and kingfishers, are known to feed on the Jewelled gecko. As far as other pest mammals, such as possums or hedgehogs, these could possibly pose a problem if encountered, but they are not a main threat to the species.[3][5]

The only known and recorded parasite for Jewelled gecko is the ectoparasite Neotrombicula naultini. [13][4]

Other Information

There is a large cultural significance tied to these and many more species of green geckos. The native Ngāi Tahu of the south island of New Zealand refer to these beautiful geckos as taonga (an object or natural resource which is highly prized) and highly thought of in their culture.[3]

See also

References

  1. 1 2 3 Hare, K.; Hitchmough, R. (2010). "Naultinus gemmeus". The IUCN Red List of Threatened Species 2010. e.T177826A7465399. Retrieved 29 November 2017.
  2. ↑ Fox, Rebecca (7 May 2011). "Time to hit smugglers". Otago Daily Times. Retrieved 7 May 2011.
  3. 1 2 3 4 5 6 7 Jewelled gecko / Moko-kākāriki management plan: a community-based plan for Otago Peninsula. Wellington, N.Z.: New Zealand Department of Conservation. 2010. pp. 3–31. ISBN 9780478148428.
  4. 1 2 3 4 5 "Naultinus Gemmeus". New Zealand Herpetological Society.
  5. 1 2 3 4 5 6 7 Knox, Marieke Lettink & Carey (2011). Looking after jewelled geckos & their habitats : a practical guide for landowners. Christchurch [N.Z.]: Dept. of Conservation, Canterbury Conservancy. ISBN 9780478148916.
  6. ↑ Hitchmough, Rod; Anderson, Peter; Barr, Ben; Monks, Jo; Lettink, Marieke; Reardon, James; Tocher, Mandy; Whitaker, Tony. "Conservation status of New Zealand reptiles, 2012" (PDF). Department of Conservation. The Government of New Zealand. Retrieved 18 July 2015.
  7. 1 2 3 Jewell, Tony; McQueen, Shirley (2007). Habitat characteristics of jewelled gecko (Naultinus gemmeus) sites in dry parts of Otago (PDF). Wellington, N.Z.: New Zealand Department of Conservation. ISBN 9780478143348. OCLC 946512798.
  8. ↑ Robb, J. (1980). "New Zealand amphibians and reptiles in colour". Collins, Auckland.: 128 p.
  9. 1 2 Wilson, Jackie L.; Cree, Alison (2003). "Extended gestation with late-autumn births in a cool-climate viviparous gecko from southern New Zealand (Reptilia: Naultinus gemmeus)". Austral Ecology. 28 (3): 339–348. doi:10.1046/j.1442-9993.2003.01293.x.
  10. ↑ Check, Al; Bowie, Mike (2009). Backyard biodiversity in Canterbury (2nd ed.). Canterbury, N.Z.: Lincoln University. ISBN 9780864762146. OCLC 423704508.
  11. ↑ Rowlands, R. P. V. (2005). New Zealand geckos : a guide to captive maintenance and breeding (4th ed.). Auckland, N.Z.: EcoPrint. ISBN 047310329X. OCLC 156742756.
  12. ↑ "Geckos". Department of Conservation. New Zealand Government. Retrieved 2018-05-04.
  13. ↑ "Naultinus gemmeus". Landcare Research. Archived from the original on 2018-05-04.
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