Liasis dubudingala

Introduction

Liasis dubudinala is the largest snake known from Australia, estimated to have been about 9 metres in length. The only known specimen of Liasis dubudinala was found at Bluff Downs in northeastern Queensland, and is Pliocene in age (about 4.5 million years old). A snake of this size may have taken juvenile diprotodontids, birds, reptiles and arboreal mammals, all common at Bluff Downs.

Identification

Liasis species are pythons, large, bulky, slow-moving constrictors in the family Boidae. The bones of the skull and lower jaw are highly kinetic (moveable) in order to swallow large prey, as in most snakes, and the skin is extensible (elastic). Liasis species differ from other snakes in having teeth on the premaxilla (a bone at the front of the snout), large, symmetrical shields (scutes) on the head, and pits in some scales along the side of the face.

Liasis dubudingala is known only from isolated vertebrae, and it is assigned to the genus Liasis on the basis of overall similarity and possession of unusually high neural spines, as in Liasis olivaceus (the Olive Python) andLiasis mackloti (the Water Python). These may give us some clue to its lifestyle: the high neural spines may indicate that Liasis dubudingala wsas arboreal (tree-dwelling).

Habitat

The Bluff Downs region during the Pliocene was an extensive wetlands bordered by patches of closed forest, perhaps like the present-day Kakadu National Park in the Northern Territory.

Distribution

Liasis dubudingala is known only from the Allingham Formation, Bluff Downs Station, northeastern Queensland. Living species of Liasis are found in Australia, New Guinea and in some parts of Indonesia.

Feeding and diet

Like other pythons, Liasis dubudingala was a non-venomous constrictor that killed by wrapping its coils around the unlucky prey and squeezing until suffocation occurred. It probably ate mammals, birds and other vertebrates, as the living Olive Python does (the specific name, dubudingala, comes from the Aboriginal Gugu-Yalanji dubu, or 'ghost', and dingal ,'to squeeze'). If it were at least partly arboreal, Liasis dubudingalamay have a wide range of prey that would have included birds and tree-dwelling mammals as well as ground-dwelling animals (perhaps even juvenile diprotodontids, which it was large enough to take).

Life history cycle

Living species of Liasis are oviparous (egg-laying), and, like other Australian pythons, incubate their eggs by coiling around them until they hatch. Liasis dubudingalaundoubtedly did the same. The Olive Python often hunts at night and will sometimes lie in wait in waterholes for its prey. Liasis dubudingala, found in freshwater deposits, may have had a similar hunting strategy.

Fossils description

Liasis dubudingala is known only from a few isolated vertebrae, representing just a single specimen. There is no known skull material, often the case with fossil snakes.

Evolutionary relationships

Liasis dubudingala is known only from isolated vertebrae, which are probably not enough for confident identification and for hypotheses about evolutionary relationships. Diagnoses of Pythoninae (the python subfamily within Boidae) may not include vertebral morphology because many vertebral characters are primitive within boids (and therefore of little use in determining relationships).

References

• Cogger, H. G., 2000. Reptiles and Amphibians of Australia (Sixth Edition). Reed New Holland, Sydney, 808 pp.
• Scanlon, J. D. and Mackness, B. S., 2001. A new giant python from the Pliocene Bluff Downs Local fauna of northeastern Queensland. Alcheringa 25, 424-437.

Further reading

Scanlon, J. D. 2006. Chapter 17: Origins and radiations of snakes in Australasia. Pp. 309-330 in Merrick, J. R., Archer, M., Hickey, G. M. and Lee, M. S. Y. (eds) Evolution and Biogeography of Australasian Vertebrates. Australian Scientific Publishing, Oatlands.