The frilled lizard (Chlamydosaurus kingii), also known as the frill-necked lizard or frilled dragon, is a species of lizard in the family Agamidae. It is native to northern Australia and southern New Guinea. This species is the only member of the genus Chlamydosaurus. Its common names come from the large frill around its neck, which usually stays folded against the lizard's body. It reaches 90 cm (35 in) from head to tail and can weigh 600 g (1.3 lb). Males are larger and more robust than females.
The frilled lizard is largely arboreal, spending most of its time in the trees. Its diet consists mainly of insects and other invertebrates. It is more active during the wet season, which is when it spends more time near or on the ground. It is less observed during the dry season, during which it seeks shade in the branches of the upper canopy. It breeds in the late dry season and early wet season. The lizard uses its frill to scare off predators and display to other individuals. The species is considered to be of least concern by the International Union for Conservation of Nature. Its distinctive appearance has been depicted in media.
British zoologist John Edward Gray described the frilled lizard in 1825 as Clamydosaurus kingii. He used a specimen collected by botanist Allan Cunningham at Careening Bay, off northwestern Australia, while part of an expedition conducted by Captain Phillip Parker King from HMS Mermaid.[3][4] The generic name, Chlamydosaurus, is derived from the Ancient Greek chlamydo (χλαμύς), meaning "cloaked" or "mantled", and Latin saurus (sauros), meaning "lizard".[5] The specific name, kingii, is a Latinised form of King.[6] It is the only species classified in its genus.[7]
The frilled lizard is classified in the family Agamidae and the subfamily Amphibolurinae. It split from its closest living relatives around 10 million years ago.[8] A 2017 mitochondrial DNA analysis of the species across its range revealed three lineages of recent divergence demarcated by the Ord River and the southeast corner of the Gulf of Carpentaria (Carpentarian Gap). One lineage ranged across Queensland and southern New Guinea and was sister to one that ranged from western Queensland to the Ord River. The ancestor of these two split from a lineage that populates the Kimberley. Frilled lizards entered southern New Guinea possibly around 17,000 years ago during a glacial cycle, when sea levels were lower and a land bridge connected the island to Cape York. The study upholds C. kingii as one species with the different populations being "shallow allopatric clades."[9]
The frilled lizard grows to a total length of around 90 cm (35 in) and a head-body length of 27 centimetres (11 in), and weighs around 600 g (1.3 lb).[11][12][9] It has a particularly large and thick head; a long neck to accommodate the frill; and long legs and a tail that makes most of its total length.[7][11][13] The species is sexually dimorphic, with males being larger than females[9][11] and having proportionally bigger frills, heads and jaws.[14] The corners of its eyes are pointed and the rounded nostrils face away from each other and angle downwards. Most of the lizard's scales are keeled, having a ridge down the centre. From the backbone to the sides, the scales alternate between small and large.[7]