Green Tree Dragon
Bronchocela cristatella (Kuhl, 1820)

Family: Agamidae - Dragons

Order: Squamata - Lizards and Snakes

Class: Reptilia

Phylum: Chordata - Vertebrates

Kingdom: Animalia

Red List status: Not evaluated

Green tree dragon. Pulau Perhentian Kecil, Malaysia.

Snout-vent length: 130 mm

Total length: 440 mm

RANGE

This is a widespread lizard through both continental Southeast Asia and the Malay Archipelago. On the mainland it occurs from Myanmar and Thailand to the tip of Peninsular Malaysia, though is absent from Indo-China. Its westernmost occurrence is in India's Nicobar Archipelago. It is found throughout Indonesia east to New Guinea, and also in the Philippines.

            Range            Description            Habitat            Behaviour            Biology            References
Other common names: Green crested lizard

 

DESCRIPTION

Adult: A slender, bright green lizard with a somewhat flattened body and long, wedge-shaped head. A nuchal crest of short, slender spines is present, which is continuous with a ridge of enlarged scales running down the length of the dorsum, but excluding the tail. A small extensible pouch is present beneath the throat in males and typically (though not exclusively) in females. The tympanum is greater than half the eye orbit diameter. The eye itself has a narrow yellow ring surrounding the pupil, and green eyelids. The body may be unpatterned, or irregular spots and bars of blue or white may be present; the lizard is capable of changing the colour of these markings to brown. The long, slender tail is green grading to brown along its length; brown bands may be present across both the body and tail, but are indistinct. The ventral surface is yellowish, and ventral scales are distinctly enlarged relative to those on the dorsum.

Similar species: Two other species of Bronchocela, Hayek's forest dragon (B. hayeki) and maned forest dragon (B. jubata) occur within the green tree dragon's range. Neither ever exhibits blue patterning; conversely, B. cristatella is never patterned red dorsally. The spines of the nuchal crest are straight in the green tree dragon, but curved in B. hayeki and B. jubata. The dorsal ridge extends down the length of the tail in the maned forest dragon. Hayek's forest dragon has a larger tympanum (almost equal to the diameter of the eye orbit). The less robust body, the poorly-developed gular pouch, and the lack of dorsal spines distinguish the species from Acanthosaura and Gonocephalus species. Juvenile Indo-Chinese water dragons (Physgnathus cocincinus) bear a superficial resemblance, but have no nuchal crest and a shorter snout.

The following combination of scale characters is diagnostic: 8-10 supralabial and 7-12 infralabial scales, 53-100 midbody and 10-12 ventral scale rows.

 

HABITAT

A species of disturbed lowland habitats; commonly encountered in forest edge habitats, gardens and parks, but also occurring at mid-elevations. It favours shrubs and tree trunks, but can also be found resting on artificial substrates such as walls, fences and telegraph wires.

Elevation: 0-1,700 m

 

BEHAVIOUR

This day-active, arboreal lizard reportedly has some capacity to glide between trees (Das, 2010), despite the absence of specialised adaptations.

Diet: The diet is known to include both flying and terrestrial insects. Small lizards (skinks) are also taken.

 

BIOLOGY

Breeding biology: Up to 4 eggs are laid at a time. These have been described as "spindle-shaped" (Das, 2010), and measure 30-35.8 mm x 8.1-11 mm. Newly-emerged hatchlings have a snout-vent length of 35 mm.

 

REFERENCES

Cox, M. J., van Djik, P. P., Nabhitabhata, J. and Thirakhupt, K. (1998) A Photographic Guide to the Snakes and Other Reptiles of Thailand, Peninsular Malaysia and Singapore. Asia Books, Bangkok, Thailand.

Das, I. (2010) A Field Guide to the Reptiles of South-East Asia. New Holland (UK), London.

Das, I. (2006) A Photographic Guide to the Snakes and other Reptiles of Borneo. New Holland (UK), London.

Manthey, U. and Schuster, N. (1996) Agamid Lizards. T.F.H. Publishing, Neptune City, NJ.

Bronchocela cristatella. Niah Caves National Park, Sarawak, Malaysia.