''Ctenophorus pictus'', commonly known as the painted ground-dragon or painted dragon,Waite ER (Editor). (1929). ''The Reptiles and Amphibians of South Australia''. Adelaide: Government Printer. 270 pp. is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

from the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Agamidae Agamidae is a family (biology), family of over 300 species of iguanian lizards indigenous to Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards. Overview phylogenetics, Phylogenetic ...

. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the drier areas of southern and central

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Description

The painted dragon is a medium-sized terrestrial lizard with a short, deep head and uniform body scales. The appearance of this species is extremely variable as it can appear in a number of different colour combinations.Wilson S, Swan G. (2013). ''A Complete Guide to Reptiles of Australia'' (Fourth Edition). London: New Holland Publishers. 592 pp. . Adult males can be brown, yellowish brown, orange to reddish brown with dark-edged pale bars, blotches or spots overlaying a dark vertebral stripe. The flanks are spotted, variegated (irregular patches/streaks), or reticulated (net-like pattern) with dark brown and dotted with scattered, pale, dark-edged spots which will sometimes be aligned perpendicular to the vertebral stripe. Cogger HG. (2014). ''Reptiles & Amphibians of Australia''. Seventh Edition. Collingwood: CSIRO Publishing. 1,036 pp. (paperback). The limbs are variegated and the pattern on the tail is often obscure but broad dark bands at the base. Breeding males will exhibit a bright blue flush over the lower lips, throat and limbs and a bright yellow to orange flush over the anterior chest and shoulders. Adult females and juveniles are duller in colour, lacking the bright blue and yellow pigment with females being commonly found in a rusty brown colour. The scales, though varying slightly in size in different parts, are relatively uniform across the body and are smooth to the touch. A low crest on the back of the neck is often present which males will raise when alarmedHoser RT. (1989). ''Australian Reptiles and Frogs''. Sydney: Pierson & Co. and usually a distinct vertebral series of slightly enlarged scales can be found along the back. The ears are exposed on the side of its head and it has rather large and conspicuous eardrums. Adults will grow to a full length of around , with a snout-to-vent length of about . The tail of this species usually accounts for about 65% of its total body length.

Distribution and habitat

Painted dragons are found throughout the drier parts of southeastern

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

, across

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

to northwestern

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

Swan, M., Watharow, S. (2005) ''Snakes, Lizards and Frogs of the Victorian Mallee'', CSIRO Publishing, Collingwood, Victoria, Australia and central-western

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

. They prefer semi-arid to arid regions, favouring shrublands and hummock grasslands on sandy and saline soils.

Ecology

Like most

agamids Agamidae is a family of over 300 species of iguanian lizards indigenous to Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards. Overview Phylogenetically, they may be sister to the I ...

, painted dragons are swift-moving reptiles, capable of impressive sprints over short distances.Wilson SK. (2012). ''Australian Lizards: A Natural History''. Collingwood: CSIRO Publishing. 208 pp. . This diurnal (day-active) lizard, like the majority reptiles, is an

ectotherm An ectotherm (from the Greek () "outside" and () "heat") is an organism in which internal physiological sources of heat are of relatively small or of quite negligible importance in controlling body temperature.Davenport, John. Animal Life a ...

meaning that it has to rely on its environment to regulate body temperature and as a result will spend considerable time basking to absorb heat. Known to be especially fond of low vegetation and ground debris such as fallen logs and branches, it occupies short burrows often concealed at the base of shrubs such as

saltbush Saltbush is a vernacular plant name that most often refers to ''Atriplex'', a genus of about 250 plants distributed worldwide from subtropical to subarctic regions. ''Atriplex'' species are native to Australia, North and South America, and Eurasia. ...

. Unlike the majority of other

which like to perch in elevated places, this species prefers to rest on low branches, from which it will forage over the surrounding open areas and ground litter. When disturbed or alarmed it will quickly retreat to the safety of the nearby burrow. Painted dragons possess many of the traits common to the family

. They are very alert lizards with an upright stance and acute vision which they will use to search for prey and keep an eye out for mates, rivals, and predators. Most of their communication is visually oriented with stylised head bops and dips, arm waving, and tail lashing playing a big part. When looking for food,

will seize their prey with the use of a short, thick tongue rather than their jaws.

Diet

Employing a sit-and-wait hunting technique, painted dragons will use their keen vision to detect most of their prey by the telltale movement they make. Accordingly, their diets consist largely of surface-active, mobile prey resulting in them consuming a range of

arthropods Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

. A strange feature of the family

is that ants, which are often avoided by other lizards, feature prominently in the diets of many of its species. While it is believed that this is more of a reflection on availability than preference, it still remains to be explained why they take ants at all when so many other lizards actively avoid them due to the

formic acid Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...

they contain. It is presumed that they have developed some sort of mechanism to deal with the ingestion of this chemical. While this species is known to be predominantly

insectivorous A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores were ...

, specimens kept in captivity have been observed supplementing their diet with considerable amounts of plant matter.

Colour polymorphism

Colouration in male painted dragon populations is extremely variable, ranging from reddish brown to orange to yellowish brown, with orange being the least common. In studies of colour polymorphism, individual lizards have been categorised by their predominant colour into three discrete groups: red, orange and yellow Higher

sexual selection Sexual selection is a mode of natural selection in which members of one biological sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of t ...

is correlated with the variable appearance of males. Between yellow and red coloured male lizards, female lizards sexually select for red-coloured males. The red colouration may indicate indirect benefits to the females, showing that the male has beneficial genes. These include having high testosterone levels, which in turn affects the ability to fight off predators and an aptitude to defend his territory and offspring. Red males have higher testosterone levels than their yellow male counterparts. Testosterone is linked to aggression; increased aggression seen from a rapid increase in testosterone levels in red lizards gives them a fighting advantage in physical competition with predators. They also show more aggressive strategies in out-competing their yellow counterparts for more mating opportunities. In addition, red males defend their territory more fiercely and begin this behaviour earlier in the year, gaining a behavioural dominance over yellow males. However, the increased aggression and early defence of territory that red lizards express has a significant metabolic expense, which decreases overall fitness. On the other hand, yellow males show high survival rates, potentially due to relatively lower energy costs in territorial defence. Furthermore, yellow males show higher sperm counts than the red lizards. Yellow males generally have larger-sized testes than red males, and they copulate for shorter periods of time. When the yellow males mate, they have, on average, three times as many offspring as their red counterparts. This dually high survivability among both red and yellow males may be why both colour morphs are maintained in painted dragon populations. While sexual selection generally favours red males,

natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charle ...

maintains variation by selecting for more energetically efficient yellow males. Both colour traits have an evolutionary advantage, which explains the maintenance of this polymorphism in nature.

Breeding colouration and oxidative stress

The breeding colouration of male ''C. pictus'' is brightly conspicuous, but declines with

aging Ageing ( BE) or aging ( AE) is the process of becoming older. The term refers mainly to humans, many other animals, and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal. In ...

. Experiments involving administration of

antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricant ...

s to ''C. pictus'' males led to the conclusion that breeding colouration is a reflection of innate anti-oxidation capacity that protects against

oxidative damage Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal r ...

, including oxidative

DNA damage DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA da ...

. Thus male breeding colouration likely acts as an indicator to females of the underlying level of

oxidative stress Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily Detoxification, detoxify the reactive intermediates or to repair the resulting damage. Disturbances ...

induced damage in potential mates.