The thorny devil (''Moloch horridus''), also known commonly as the mountain devil, thorny lizard, thorny dragon, and moloch, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Agamidae Agamidae is a family containing 582 species in 64 genera of iguanian lizards indigenous to Africa, Asia, Australia, and a few locations in Southern Europe. Many species are commonly called dragons or dragon lizards. Overview Phylogenetically ...

. The species is

endemic Endemism is the state of a species being found only 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 foun ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. It is the sole species in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Moloch''. It grows up to in total length (including tail), with females generally larger than males.

Taxonomy

The thorny devil was first described by the biologist

John Edward Gray John Edward Gray (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for a z ...

in 1841. While it is the only species contained in the genus ''Moloch'', many taxonomists suspect another species might remain to be found in the wild. The thorny devil is only distantly related to the morphologically similar

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

horned lizard ''Phrynosoma'', whose members are known as the horned lizards, horny toads, or horntoads, is a genus of North American lizards and the type genus of the Family (biology), family Phrynosomatidae. Their common names refer directly to their horns or ...

s of the genus ''Phrynosoma''. This similarity is usually thought of as an example of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

. The names given to this lizard reflect its appearance: the two large horned scales on its head complete the illusion of a dragon or devil. The name

Moloch Moloch, Molech, or Molek is a word which appears in the Hebrew Bible several times, primarily in the Book of Leviticus. The Greek Septuagint translates many of these instances as "their king", but maintains the word or name ''Moloch'' in others, ...

was used for a deity of the

ancient Near East The ancient Near East was home to many cradles of civilization, spanning Mesopotamia, Egypt, Iran (or Persia), Anatolia and the Armenian highlands, the Levant, and the Arabian Peninsula. As such, the fields of ancient Near East studies and Nea ...

, usually depicted as a hideous beast. The thorny devil also has other nicknames people have given it such as the "devil lizard", "horned lizard", and the "thorny toad".

Description

The thorny devil grows up to in total length (including tail), and can live for 15 to 20 years. The females are larger than the males. Most specimens are coloured in camouflaging shades of desert browns and tans. These colours change from pale colours during warm weather to darker colours during cold weather. The thorny devil is covered entirely with conical spines that are mostly uncalcified. Thorny devil pale

An intimidating array of spikes covers the entire upper side of the body of the thorny devil. These thorny scales also help to defend it from

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

Camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

and deception may also be used to evade predation. This lizard's unusual gait involves freezing and rocking as it moves about slowly in search of food, water, and mates. The thorny devil also features a spiny "false head" on the back of its neck, and the lizard presents this to potential predators by dipping its real head. The "false head" is made of soft tissue. The thorny devil's scales are ridged, enabling the animal to collect water by simply touching it with any part of the body, usually the limbs;

capillary action Capillary action (sometimes called capillarity, capillary motion, capillary rise, capillary effect, or wicking) is the process of a liquid flowing in a narrow space without the assistance of external forces like Gravitation, gravity. The effe ...

transports the water to the mouth through channels in its skin. The thorny devil is also equipped to harvest moisture in the dry desert following nighttime's extremely low temperatures and the subsequent condensation of

dew Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening due to condensation. As the exposed surface cools by thermal radiation, radiating its heat, atmospheric moisture condenses at a rate grea ...

. The process involves moisture contact, their hydrophilic skin surface structures with capillaries, and an internal transport mechanism. *The lizard rubs its body against the moist substrate and shovels damp sand onto its back, the outer epidermis layer equipped to draw in cutaneous moisture. *The keratinous fibered epidermis is hydrophilic with hexagonal microstructures on the scale surfaces. When trace amounts of water contact its skin (pre-wetting) these microstructures fill with water, the skin surface becoming superhydrophilic. This allows moisture to spread across wider surface areas, yielding faster uptake, as water is collected via capillary action in small channels located between its scales. *Captured water is transported passively via capillary action in semi-tubular channels located beneath the partially overlapping scales, in an asymmetric and interconnected system that extends over the lizard's entire body surface. The channels terminate at the mouth where active ingestion (drinking) is observable by jaw movements when moisture is plentiful, e.g. water puddles. The same hydrophilic moisture-harvesting physiology is characteristic in the Texas horned lizard (''Phrynosoma cornutum''), roundtail horned lizard ('' Phrynosoma modestum''), desert horned lizard (''Phrynosoma platyrhinos''), Arabian toad-headed agama ('' Phrynocephalus arabicus''), sunwatcher toadhead agama ('' Phrynocephalus helioscopus''), '' Phrynocephalus horvathi'', yellow-spotted agama ('' Trapelus flavimaculatus''), ''Trapelus pallidus'' and desert agama ('' Trapelus mutabilis'').

Distribution and habitat

The thorny devil usually lives in the arid

scrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominance (ecology), dominated by shrubs, often also including grasses, herbaceous plant, herbs, and geophytes. Shrubland may either occur naturally o ...

and

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

that covers most of

central Australia Central Australia, also sometimes referred to as the Red Centre, is an inexactly defined region associated with the geographic centre of Australia. In its narrowest sense it describes a region that is limited to the town of Alice Springs and ...

, sandplain and sandridge desert in the deep interior and the mallee belt. The habitat of the thorny devil coincides more with the regions of sandy

loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–si ...

soils than with a particular climate in

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

Self-defense

The thorny devil is covered in hard, rather sharp spines that dissuade attacks by predators by making it difficult to swallow. It also has a false head on its back. When it feels threatened by other animals, it lowers its head between its front legs, and then presents its false head.

Predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

s that consume the thorny devil include wild birds and goannas.

Diet

The thorny devil mainly subsists on ants, especially '' Ochetellus flavipes'' and other species in the ''

Camponotus Carpenter ants (''Camponotus'' spp.) are a genus of large ants (workers ) indigenous to many parts of the world. True carpenter ants build nests inside wood, consisting of galleries chewed out with their mandibles or jaws, preferably in dead, ...

'', '' Ectatomma'', ''

Iridomyrmex ''Iridomyrmex'' is a genus of ants called rainbow ants (referring to their blue-green iridescent sheen) first described by Austrian entomologist Gustav Mayr in 1862. He placed the genus in the subfamily Dolichoderinae of the family Formicida ...

'' (especially '' Iridomyrmex rufoniger''), '' Monomorium'', '' Ochetellus'', '' Pheidole'', or '' Polyrhachis'' genera. Thorny devils often eat thousands of ants in one day. The thorny devil collects moisture in the dry desert by the condensation of dew. This dew forms on its skin in the early morning as it begins to warm outside. Then the dew is channeled to its mouth by gravity and

via the channels between its spines. During rainfalls, capillary action allows the thorny devil to absorb water from all over its body. Capillary action also allows the thorny devil to absorb water from damp sand. Absorption through sand is the thorny devil's main source of water intake.

Reproduction

The female thorny devil lays a clutch of three to ten

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

s between September and December. She puts these in a nesting burrow about 30 cm underground. The eggs hatch after about three to four months.

Popular reference

The popular appeal of the thorny devil is the basis of an anecdotal petty scam. American servicemen stationed in

Southwest Australia Southwest Australia is a biogeographic region in Western Australia. It includes the Mediterranean-climate area of southwestern Australia, which is home to a diverse and distinctive flora and fauna. The region is also known as the Southwest Au ...

decades ago (such as during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

) were supposedly sold the thorny fruits of a species of weeds, the so-called "double gee" ('' Emex australis''), but those were called "thorny devil eggs" as a part of the scam. Thorny devils have been kept in captivity.

References

External links

Digimorph: ''Moloch horridus'', thorny dragon body structure

www.kidcyber.com.au {{Taxonbar, from=Q320665 Agamidae Reptiles of Western Australia Reptiles described in 1841 Agamid lizards of Australia Taxa named by John Edward Gray Moloch