LIZARDS OF THE WET TROPICS

Boyd's forest dragon

(Hypsilurus boydii)

DISTRIBUTION:

North-eastern Queensland, from Cooktown south to Townsville.

HABITAT:

Rainforest.

DESCRIPTION (from Cogger, 1992; Wilson and Knowles, 1988):

A moderately large, laterally compressed agamid with a large, wedge-shaped head and a thick, angular canthus rostralis, continuous with a supraocular ridge. Generally brown or grey above with some specimens having a green flush. There is a large yellow dewlap edged with enlarged spines. There are also enlarged plates on the cheeks and spines atop the large nuchal crest. A dorsal crest, discontinuous with the nuchal crest, consisting of enlarged, hardened and pointed scales, runs down to the base of the tail. The tympanum is large and superficial. Male SVL = 160mm; female SVL=145mm.

REPRODUCTION (Torr, unpub. data):

Clutch sizes of 1-5 have been recorded. Lizards in lowland rainforest probably produce multiple clutches in a season (October-February?) whilst upland animals lay one clutch per year or one every two years. Lizards at Paluma (the southern limit of the species' range) lay during the first few weeks of December. Clutch sizes and egg sizes are significantly larger in upland lizards. Females lay their eggs in areas where the canopy is open - either in tree falls or beside roads. Nests consist of a shallow burrow covered in a few centimeters of soil and leaf litter. Incubation times appear to be in the order of two months and DIET:

Invertebrates - mainly ants, beetles, grasshoppers and earthworms.

NOTES:

Unlike most other agamids Boyd's forest dragons apparently do not thermoregulate - body temperatures are generally within a degree of ambient. Forest dragons are arboreal and are usually observed perching on small trees at a height of approximately 1-2m. Known predators include Grey Goshawks (R.Russel, pers.comm.) and feral pigs (Pavlov, 1995).

REFERENCES:

Barnett, B. 1981. Observations of fish feeding in reptiles. Herpetofauna 13: 11-13.

Cermak, M. Breeding reptiles at Wild World Australia (Cairns).

Cogger, H. G. 1992. Reptiles and Amphibians of Australia. Reed Books, Sydney.

Ehmann, H. 1992. Encyclopedia of Australian Animals. Angus and Robertson, Sydney.

Hawkes, T. A report of a communal gathering of gravid Boyd's rainforest dragons Hypsilurus boydii. Chondro 1: 58-59.

Nix, H. and Switzer, M. A. 1991. Rainforest Animals: Atlas of the Vertebrates Endemic to Australia's Wet Tropics. Kowari, Canberra.

Ota, H., Matsui, M., Hikida, T. and Mori, A. 1992. Extreme karyotypic divergence between species of the genus Gonocephalus (Reptilia: Squamata: Agamidae) from Borneo and Australia. Herpetologica 48: 120-124.

Pavlov, P. M. 1995. Cape Tribulation Feral Pig Study. Unpublished report for the Department of Environment and Heritage.

Torr, G. A. 1993. The ecology of Boyd's forest dragon, Hypsilurus boydii. Unpublished report for the Wet Tropics Management Agency.

Wilson, S. K. and Knowles, D. G. 1988. Australia's Reptiles; a photographic reference to the terrestrial reptiles of Australia. Collins, Sydney.

Prepared by: Geordie Torr, Dept. of Zoology, James Cook University, QLD 4811, Australia.

Geordie.Torr1@jcu.edu.au

Last updated: April, 1995.