Naultinus
Naultinus | |
---|---|
Northland green gecko (Naultinus grayii) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Family: | Diplodactylidae |
Genus: | Naultinus Gray, 1842 |
Species | |
See text | |
Naultinus range species indicated
|
Naultinus is a
While historically widespread and quite common in areas of native forest all over the country, all species in this genus are of conservation concern in the present day. All nine species of Naultinus are declining in the wild and are much harder to find than they used to be; the populations of the various species are highly fragmented and approaching extinction, while others in the genus have already gone extinct. Entire populations of certain species, with unique traits and distinctive genetic profiles, have disappeared in the last 20 years. The primary known agents of this catastrophic decline include predation by invasive mammalian and avian species, habitat destruction and poaching for the illegal pet trade. Vespid wasp predation is speculated to be another possible contributing cause. Legal protection in the form of longer prison sentences for poachers caught with New Zealand protected species has been increased in recent years and translocations of various species to pest free islands have been undertaken with mixed results, but the task of saving these animals remains daunting. The behavioural and visually cryptic nature of these animals also pose challenges to their conservation management. The genus is, in general, in "dire need of research, particularly into factors that are causing their apparent decline", certain aspects of which remain unexplained.[3]
Taxonomy
The following nine described species are recognized as being valid.[4] A binomial authority in parentheses indicates that the species was originally described in a genus other than Naultinus.
- Naultinus elegans Gray, 1842 – Auckland green gecko
- Naultinus gemmeus (McCann, 1955) – jewelled gecko
- Naultinus grayii Bell, 1843 – Northland green gecko, Gray's tree gecko
- Naultinus manukanus(McCann, 1955) – Marlborough green gecko, northern tree gecko
- Naultinus punctatusGray, 1843 – Wellington green gecko
- Naultinus rudis (Fischer, 1881) – rough gecko, natural tree gecko
- Naultinus stellatus Hutton, 1872 – Nelson green gecko, starry tree gecko
- Naultinus tuberculatus (McCann, 1955) – West Coast green gecko,[7]Lewis Pass green gecko
Defining what constitutes a species among different populations within this genus has proved difficult and is still a matter of some scientific debate. Genetic evidence suggests that all nine species share an ancestor which is "very recent" in deep time terms and that hybridization between them is quite common. All species will interbreed in the wild, which has led some biologists to reject the notion of multiple Naultinus species and to instead view each "species" as a separate "race" or subspecies of a single, very widespread species of this genus. However, there are many clear differences between recognized species in colouration, breeding times and even scale morphology. Many neighbouring species have slightly different mating seasons and behaviour, which is thought to explain why the species maintain their differences despite "strong reproductive compatibility". These differences are the basis for the present consensus in the scientific community that Nautilnus is constituted of nine species instead of nine races of a single species.[3]
Genetically speaking, the
Description
Naultinus species are commonly known as "green geckos" in New Zealand for their striking bright green colouration. In addition, they are
Naultinus species and indeed, New Zealand lizards in general, are very conservative in their evolutionary development of
All Naultinus species also possess very long, finely tapered, strongly
Summary table of the key differences between Naultinus and Hoplodactylus
There are many key differences in physiology and behaviour between species of NZ gecko in the two endemic genera, summarised in the table below:[10][12]
Hoplodactylus | Naultinus |
---|---|
Mainly grey-brown | Mainly green |
Nocturnal | Diurnal |
Terrestrial, sometimes on tree trunks | Arboreal, on foliage |
Active-prey-searching | Sit-and-wait predator |
Generally fast-moving | Generally slow-moving |
Can change intensity of skin colour | Skin colour intensity cannot be changed |
Wide, non-prehensile tails, readily shed | Narrow, tapering prehensile tails, reluctantly shed |
Some have wider toe pads with claws, adapted for climbing smooth, vertical surfaces | Thin toe pads adapted for grasping twigs and foliage |
Distribution and habitat
The nine described species of Naultinus are found throughout the North and South islands of New Zealand and on a number of offshore islands. Historically, Naultinus species lived throughout the length of New Zealand, from the coast to as much as 1400 metres above sea level. However, all species have now undergone massive declines, and populations nationwide are fragmented and few (see "
None of the Naultinus gecko populations are
Behaviour and ecology
Activity patterns and diet
Most of the world's two thousand-odd species of geckos are active by night (
Predators and parasites
New Zealand geckos have very few natural predators;[9] although several species of native bird will take them as prey only the sacred kingfisher kills very many.[9] The Tuatara, a large, ground dwelling, generalist predator, will feed on native geckos, including Naultinus, where the two occur together on a few predator-free offshore islands.[9] All New Zealand geckos, including Naultinus (but particularly Hoplodactylus species) carry small orange-red skin mites which gather around the eyes, the base of limbs, ear openings and skin folds.[11] These mites, while essentially harmless, do suck small amounts of blood from their hosts, in time becoming quite swollen and taking on their characteristically vivid colouration as a result.[11]
Thermoregulation
As
Defensive behaviour in North Island Naultinus
The four species of North Island Naultinus exhibit, to varying degrees,
Reproduction and life history
While most species of geckos in other parts of the world live for just a few years, Naultinus are very long lived in comparison - they have been known to live for 30 years or more
Naultinus and humans
In culture
Reptiles in New Zealand were well known to Māori in pre-European times and featured in many carvings,[9] some of which obviously depict tuatara and others which depict lizards.[9] The body shape of many examples suggests that they are geckos, though skinks also seem to be depicted.[9] With the exception of the Tuatara, which was frequently eaten, lizards were regarded with abhorrence by Māori and Naultinus in particular; sightings of Naultinus were regarded as bad omens.[9]
As pets
Naultinus can legally be kept in captivity as pets in New Zealand, provided one has an appropriate permit from
Naultinus are also kept in captivity by enthusiasts in overseas countries but it should be stressed that trade is incredibly difficult, and one must obtain adequate CITES permits for importation and exportation. This process is regulated by the CITES Management Authority, which ascertains whether or not founding stock were obtained by a keeper in a particular country prior to 1981. This is often quite difficult, and usually prohibitive of international trade between Europe (where most stock resides outside of New Zealand) and other countries.
Threats and decline
Collectively, the species of genus Naultinus have a very wide range over most of New Zealand's land area and yet all of them are now increasingly rare and hard to find.[8] This is in stark contrast to anecdotal reports among NZ herpetoculturalists who found them abundant in suitable habitat (such as regenerating bush in the Marlborough Sounds) in the 1960s from which they have now all but vanished. The three major factors thought to be responsible for this decline are; habitat destruction, predation by introduced mammalian species and poaching for the illegal pet trade.
Barking geckos were common in shrublands all around the Wellington region up until the 1960s and 1970s
Predation by invasive species
Naultinus are preyed on by a number of invasive mammalian species including cats,
Habitat destruction
Habitat destruction by the encroachment of suburban areas into forested Naultinus habitat both directly destroys the ecosystems in which the animals live, as well as also facilitating further decline by increasing the size of local cat and rodent populations.[3] A unique population of Naultinus gemmeus near Hakatarema Pass, east of Twizel which displayed unusual colouration and a distinctive genetic profile was entirely destroyed when its forest habitat was cleared by a bulldozer for urban development.[3]
Poaching
New Zealand's Naultinus are highly prized by international lizard collectors for three main reasons; firstly they have very attractive colouration and indeed, have been referred to by some as "the world's most beautiful geckos". Secondly, they are day active and so are out and about when their keepers are awake
In early 2010 a Mexican man and a Swiss national with US citizenship were caught in Christchurch airport attempting to smuggle 16 Naultinus gemmeus out of the country. They were jailed for 15 weeks – not enough to have them banned from ever returning to NZ –something that DOC are investigating changing for future cases.[18] The Judge for the case, Judge Raoul Neave commented that "a significant increase in the sentencing could be desirable" in such cases.[18] Naultinus have also been illegally taken/stolen from wildlife parks in the past; one rudis and two grayi were stolen from Orana Wildlife Park in 2006 though they were later found, unharmed, by police; their captors, two local New Zealand citizens, were arrested and charged.[19]
Conservation
There is a critical lack of scientific research that has been done on Naultinus species and this fact, combined with the behaviourally and visually cryptic nature of the genus pose major challenges to their conservation management.[20] For many Naultinus species, (examples include grayii,stellatus and rudis) there is a complete lack of accurate data in key areas such as distribution, abundance and recruitment rate (primarily because they are visually and behaviourally cryptic)- these types of information are critical to developing conservation management plans and make the conservation status of these species very difficult to determine;[8] Some species have not had a single scientific study carried out on them, simply because they are so hard to find. The behaviourally cryptic aspect relates to the previously described behaviour whereby Naultinus will descend to ground level to hide in vegetation and shelter from cold and poor weather conditions; whole populations will appear to vanish and no amount of searching will turn them up,[3] only for them to "reappear" when the weather improves.[3] These "disappearing acts" have meant that the local extinction of many Naultinus populations has been overlooked because they were temporarily dismissed as simply being hard to find while sheltering from bad weather.[3]
Searches for Naultinus are often inconclusive because the animals simply avoid detection.[3] Improved detection methods would allow scientists to monitor populations much more accurately and a number of different studies in recent years have been doing research into this area – some key ideas are a new type of cover mounted on trees for animals to hide in, pheremone lures and even terriers trained to pick up on the scent of native geckos. Naultinus have been reintroduced to some predator free areas and are present at other locations where their habitat is protected and where pest control is being carried out but because Naultinus have a very slow breeding rate, recovery of populations is inevitably a relatively slow and gradual process.[9]
References
- OCLC 1048295078.)
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- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Jewell, Tony (November 2008). "Vanishing Geckos". Forest and Bird Magazine (330).
- ^ "Naultinus ". The Reptile Database. www.reptile-database.org.
- S2CID 232340550.
- ^ "Naultinus 'North Cape' | NZHS". www.reptiles.org.nz. Retrieved 24 January 2021.
- ^ "JCVI.org". Archived from the original on 21 May 2010. Retrieved 24 May 2010.
- ^ a b c d e f g h i j Rod Morris and Allison Ballance, Rare Wildlife of New Zealand, Random House, 2008
- ^ a b c d e f g h i j k l m n o p q r s t u v w x R. P. V. Rowlands,New Zealand Geckos: A Guide to Captive Maintenance and Breeding (rev. ed.), Ecoprint, 1999
- ^ a b c d e f g h i Brian Gill and Tony Whitaker, New Zealand Frogs and Reptiles, David Bateman Pubg., 1996
- ^ a b c d e f g h i Joan Robb, New Zealand Amphibians and Reptiles, Collins, 1980
- ^ Gibbs, George (2006). Ghosts of Gondwana; the History of Life in New Zealand. Craig Potton Publishing.
- ^ Rob Hitchmough- Threatened species science section, DOC, (August 2006)
- ^ "Gecko's Bark Throws Moggy", Simon Edwards, The Hutt News, 24 May 2005
- ^ David Wilkinson, "Analysis of Annual Returns for the 2003 Calendar Year", MOKO: Newsletter of the New Zealand Herpetological Society, February 2005
- ^ Ngaire Jury and Heather Barton,'"Release to Mana", MOKO: Newsletter of the New Zealand Herpetological Society, June 2005
- ^ Bruce Hudson, illustrated by TJ Thornton, "Reptiles and Amphibians in New Zealand - Handbook for species identification", Print media specialists, 1994
- ^ a b "Smugglers of Wildlife face Prison", Keith Lynch, The Press, 30 March 2010
- ^ "Stolen Geckos Found as Police Raid Home", Jarrod Booker, New Zealand Herald, 13 April 2006
- ^ Kelly M. Hare, Joanne M. Hoare, Rodney A. Hitchmough, "Investigating Natural Population Dynamics of Naultinus Manukanus to Inform Conservation Management of New Zealand's Cryptic Diurnal Geckos", Journal of Herpetology 41(1):81-93. 2007
Further reading
- Gill, Brian; Whitaker, Tony. 1996. New Zealand Frogs and Reptiles. Glenfield, New Zealand: David Bateman Ltd. 112 pp. ISBN 978-1869532642.
- Gray, J.E. 1842. "Descriptions of two hitherto unrecorded species of Reptiles from New Zealand; presented to the British Museum by Dr. Dieffenbach". Zoological Miscellany 2: 72. (Naultinus, new genus).
- Rowlands, Rodney Peter Victor. 2011. New Zealand Geckos: A Guide to Captive Maintenance and Breeding. Auckland, New Zealand: EcoPrint. 60 pp. ISBN 978-0473103293(2005 edition).