Draco (lizard)

Source: Wikipedia, the free encyclopedia.

Draco
D. taeniopterus in mid-glide, on Bulon Island, Thailand
Male D. spilonotus extending the dewlap (throat flap) and patagia ("wings") in Sulawesi, Indonesia
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Iguania
Family: Agamidae
Subfamily: Draconinae
Genus: Draco
Linnaeus, 1758
Species

41 species (see text)

Draco is a

insectivores
.

While not capable of powered flight they often obtain lift in the course of their gliding flights. Glides as long as 60 m (200 ft) have been recorded, over which the animal loses only 10 m (33 ft) in height which makes for a

glide ratio of 6:1. This is done by a lizard of only around 20 cm (7.9 in) in total length, tail included.[2] They are found across Southeast Asia and southern India and are fairly common in forests, areca gardens, teak plantations and shrub
jungle.

History of discovery

mythology. In the early and mid 20th century, there was controversy about their gliding capabilities, with some authors suggesting that the patagia were solely for display, but research in the late 1950s firmly established the gliding function of the patagia.[3]

Distribution

Species of Draco are widely distributed in the forests of Southeast Asia, with one species, Draco dussumieri, inhabiting Southern India.[4]

Habitat and ecology

Members of Draco are primarily

tree bark; both are likely to be camouflage against predatory birds.[6]

Gliding

Takeoff and initial stages of gliding, slowed down 10x, showing the attachment of the forelimbs to the gliding membrane
Landing, slowed down 20x

The lizards are well known for their "display structures" and ability to glide long distances using their

Gliding is both used to escape predators, and as the primary means of moving through their forest habitat.[3] The folding and unfolding of the membrane is controlled by the iliocostalis and intercostal muscles, which in other lizards are used to control breathing. At takeoff, the lizard jumps and descends headfirst, orientating itself so that the underside of the body is parallel to the ground. During flight, the back arches, forming the patagium into a cambered surface, and the forelimbs grab the front of the patagium, forming a straight front edge to the aerofoil. The forelimbs are used to manipulate the patagium in order to adjust the trajectory during flight. Maximum gliding speeds have been found to be between 5.2 and 7.6 metres per second, depending on the species. During the landing process, the glide is mostly horizontal. Immediately before landing, the forelimbs release the patagium. The landing is forefeet-first, followed by hindfeet.[8] The shape of the gliding membrane does not correlate with body size, meaning the larger species have proportionately less lift-generating surface area and consequently higher wing loading.[9]

Life history

Draco lizards are

eggs. She descends the tree she is on and makes a nest hole by forcing her head into the soil. She then lays a clutch of 2–5 eggs before filling the hole and guards the eggs for approximately 24 hours, but then leaves and has nothing more to do with her offspring.[2]

Phylogenetics

Within Agamidae, Draco is a member of the subfamily Draconinae. Within Draconinae, Draco is most closely related to the genera Japalura and Ptyctolaemus.[13]

Species

Male D. dussumieri displaying for females by extending his dewlap, from Dandeli, India
Size of D. quinquefasciatus in comparison to a human hand, from Sarawak, Malaysia
Highly camouflaged D. dussumieri from Bandipur National Park, India

The following 41 species are recognized:[1][14]

Nota bene: a binomial authority in parentheses indicates that the species was originally described in a genus other than Draco.

Similar prehistoric reptiles

fossil record have convergently evolved similar gliding mechanisms consisting of a patagium or plate flanking the torso; the weigeltisaurids are the oldest of these, living in the Late Permian from around 258 to 252 million years ago. Other lineages include the Triassic kuehneosaurids and Mecistotrachelos, and the Cretaceous lizard Xianglong.[3][8]

See also

References

  1. ^ a b Draco at the Reptarium.cz Reptile Database. Accessed 8 June 2021.
  2. ^
    Greenwood Press[dubious
    ].
  3. ^ .
  4. .
  5. .
  6. .
  7. .
  8. ^ .
  9. .
  10. .
  11. .
  12. doi:10.1111/bij.12319. "Similarly, in some Draco it has been suggested that females have larger heads for their body size than males to counterbalance an increased weight burden that is displaced posteriorly during gravidity
    ."
  13. .
  14. ^ "Draco ". Dahms Tierleben. www.dahmstierleben.de.
  15. . (Draco beccarii, p. 21).

Further reading