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Eastern water dragon -  Physignathus lesueurii

From Wikipedia, the free encyclopedia

 

The Australian water dragon (Intellagama lesueurii, formerly Physignathus lesueurii [1]), which includes the eastern water dragon (I. l. lesueurii ) and the Gippsland water dragon (I. l. howittii ) subspecies, is an arboreal agamid species native to eastern Australia from Victoria northwards to Queensland. There may be a small introduced population on the south-east coast of South Australia.

Water dragon

Scientific classification :

Kingdom:Animalia

Phylum:Chordata

Class:Reptilia

Order:Squamata

Suborder:Iguania

Family:Agamidae

Genus:Intellagama
Wells & Wellington, 1985

Species:I. lesueurii

Binomial name:

Intellagama lesueurii
(Gray, 1831)

Subspecies :

  • I. l. lesueurii (Gray, 1831)eastern water dragon

  • I. l. howittii (F. McCoy, 1884)Gippsland water dragon

Synonyms[1][2]:

  • Lophura lesueurii Gray, 1831

  • Istiurus lesueurii— A.M.C. Duméril & Bibron, 1837

  • Iguana panamatensisFitzinger, 1843

  • Amphibolurus maculiferusGirard, 1857

  • Amphibolurus heterurusW. Peters, 1866

  • Amphibolurus branchialisDe Vis, 1884

  • Physignathus lesueurii— Boulenger, 1885

  • Intellagama lesueurii— Wells & Wellington, 1985

Intellagama lesueurii howittii

Etymology :

 

The specific name, lesueurii, is in honor of French naturalist Charles Alexandre Lesueur.[3]

 

Description  :

 

Australian water dragons have long powerful limbs and claws for climbing, a long muscular laterally-compressed tail for swimming, and prominent nuchal and vertebral crests.[4] (A nuchal crest is a central row of spikes at the base of the head. These spikes continue down the spine, getting smaller as they reach the base of the tail.)[5]

 

Including their tails, which comprise about two-thirds of their total length, adult females grow to about 60 cm (2 feet) long, and adult males can grow slightly longer than one metre (3 feet) and weigh about 1 kg. Males show bolder colouration and have larger heads than females.[6][7] Colour is less distinct in juveniles.[8]

 

Species variation :

 

The Australian water dragon is the only species of the genus Intellagama.[1]

 

There are two subspecies; Intellagama lesueurii lesueurii (eastern water dragon) and I. l. howitti (Gippsland water dragon). I. l. lesueurii tends towards white, yellow and red on the throat and possesses a dark band behind its eye; I. l. howitti lacks this and instead has dark bands on either side of its throat, which is blotched with yellow, orange, or blue. Both subspecies are light greenish grey in overall colour with black bands running across their back, tail and legs. The water dragon can slowly change skin colour to aid its camouflage. The skin will shed during periods of growth.

Behaviour :

 

Australian water dragons are extremely shy in the wild, but readily adapt to continual human presence in suburban parks and gardens. They are fast runners and strong climbers. When faced with a potential predator, they seek cover in thick vegetation, or drop from an overhanging branch into water. They are able to swim totally submerged, and rest on the bottom of shallow creeks or lakes for up to 90 minutes,[5] to avoid detection.

 

Both males and females display typical agamid behaviour such as basking, arm-waving and head-bobbing. Fast arm-waving signals dominance, while slow arm-waving signals submission. Males are territorial,[4] and in areas of higher population density, males exhibit displays of aggression toward other males including posturing, chasing and fighting.

 

Breeding :

 

Australian water dragons living in cooler Australian climates hibernate over winter. During spring, usually in early October, the female excavates a burrow about 10–15 cm (3.9–5.9 in) deep and lays between 6 and 18 eggs.[4] The nest is usually in sandy or soft soil, in an area open to sun. When the mother has laid the eggs, she backfills the chamber with soil and scatters loose debris over it. Australian water dragons exhibit temperature dependant sex determination; the sex of the hatchlings is determined by the temperature of the nest site.[5]

 

When the young are born they stay near the entrance of the burrow for some time before leaving home. When they finally leave the nest, they tend to group together away from the adult population.[6]

Habitat :

 

As its name suggests, the Australian water dragon is associated with water and is semi-aquatic. It can be found near creeks, rivers, lakes and other water bodies that have basking sites such as overhanging branches or rocks in open or filtered sun. The species is very common in the rainforest section of Brisbane Botanic Gardens, Mount Coot-tha in Queensland, and a monument has been built to them there.

 

There are anecdotal reports of a small colony living on the Sixth Creek in the Forest Range area of South Australia, which were probably introduced there during the 1980s by a local reptile enthusiast. This is many hundreds of miles outside their natural range.

Eastern water dragon

I. l. howitti, Gippsland water dragon basking in Canberra

Basking water dragon in City Botanic Gardens.

Predators, threats and diet :

 

Australian water dragons are prey to birds, snakes, cats, dogs and foxes. Nestlings and smaller juvenile water dragons are vulnerable to predation by kookaburras, currawongs, butcherbirds and other carnivorous birds.[9] They are also prone to becoming road kill due to the attraction of warm bitumen and concrete for basking.[9] The Australian water dragon's diet depends on its size. Juveniles and yearlings tend to feed on small insects such as ants, spiders, crickets, and caterpillars. When they get bigger, so does their prey. An adult diet includes small rodents such as baby mice, although insects are still the most commonly consumed.

Gallery :

Juvenile eastern water dragon in Roma Street Parkland, Brisbane, Queensland, Australia

Eastern water dragon at Brisbane Botanic Gardens

Head of an eastern water dragon poking out of a pond in Brisbane Botanical Gardens

Eastern water dragon at Brisbane Botanic Gardens

Australian eastern water dragon basking in the sun at Blue Mountains (New South Wales)

I. l. lesueurii swimming, Shoalhaven River, New South Wales

Two male Australian eastern water dragons (Physignathus lesueurii ) fighting.

Swimming across river in Melbourne

Australian water dragon surveying Sydney Harbour

Intellagama lesueurii lesueurii (eastern water dragon)

Head detail of the eastern subspecies

Australian water dragon, Brisbane

Video : 

Yes, there are dragons in the Gardens ...

courtesy to :www.anbg.gov.au/gardens/visiting/exploring/fauna/reptiles/dragon.html

For the external links , refrences  click here to read the full wikipedia article 

Eastern water dragons in suburbia [HD] Off Track, ABC RN

What are Water Dragons ?

 

Identification: Water Dragons in Australia can be up to 1 metre, with long powerful legs and claws. Their tail forms 2/3 of their length and is almost all muscle. It is laterally compressed to help act like an oar when swimming. The Water Dragon has a nuchal crest – a central row of enlarged spikey spines at the back of the head. These spikes continue down the spine, decreasing in size to the base of the tail. At the tail the spines divide into two rows.

 

The Water Dragon’s upper body is a grey-green with cream and black transverse bands on the body and tail. Underneath the body is creamy brown-grey. They have loose folds of skin under the jaw, giving them an almost Bearded Dragon appearance.

 

Subspecies differences: The Eastern Water Dragon (Intellagama lesueurii lesueurii) has a dark stripe from ear to eye, that the Gippsland Water Dragon (Intellagama lesueurii howitti) lacks. The Eastern Water Dragon male has a red flush on its chest and darker bands. The Gippsland Water Dragon male has an olive-grey chest, and is distinguished with a colourful throat that is blotched or striped with various colours; orange, blue and yellow.

 

Sexual and age differences: Juvenile Water Dragons are light brown in colour, with head and feet disproportionately large compared with the adults. The female Water Dragons lack the bright colourations on the chest and throat, and have narrower, more delicate heads. The male Water Dragon’s head is much larger and angular.

Swimming: Water Dragons as their name suggests are semi-aquatic lizards. They spend a lot of time perching in trees along creeks and rivers. At any sign of danger they will dive into the water and either remain underwater or swim away. Water Dragons have been known to remain underwater for up to 90 minutes. Water Dragons when underwater slow their heart rate and conduct some gas exchange across their skin, both O2 and CO2.

Running: Water Dragons at slow speeds run on all four legs, but to increase their running speed they can run on their back legs only (bipedally). Their long powerful back legs and sharp claws help in their abilities to climb trees and dig holes for hibernation and nesting.

Eating: Water Dragons are omnivorous (eat both plant and animal matter). They generally feed on insects, frogs, yabbies, other aquatic organisms, fruits, berries and flowers. They can eat under water. There has been recorded incidents of cannibalism occurring to young hatchlings.

 

More Information :

Taxonomy of Water Dragons

Distribution of Water Dragons

Reproduction in Water Dragons

Predators of Water Dragons

Recent research projects

Results of research projects

FAQ - Water Dragon facts

When to see them at the Australian National Botanic Gardens

Where to find them in the Botanic Gardens

Bibliography

Web links

In the Botanic Gardens we have Gippsland Water Dragons, lacking the dark stripe from ear to eye. This is a male.

Further Reading : 

Anoles, Basilisks, and Water Dragons (Complete Pet Owner's Manual)Paperback – March 1, 2008

 

by R.D. Bartlett (Author), Patricia Bartlett (Author)

-  Water Dragons (Complete Herp Care) Kindle Edition

 

by Bert Langerwerf  (Author)

Keeping Australian Water Dragons Paperback – December 1, 2006

 

by Jason Goulding (Author), Darren Green (Author)

Agamidae :  Introduction 

Agamidae Species : Africa  -  Asia  -  Australia & Papua new guinea

-   Species and subfamilies list :   (  Papua New Guinea  ) 

 

- Genus :   Hypsilurus         Part 1   Part 2

-   Species and subfamilies list :   (  Papua New Guinea  ) 

 

- Genus :   Hypsilurus         Part 1   Part 2

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