Friday, February 13, 2009

Searching for Tyrannosaurus Rex

The possibility of a living theropod in Arnhem land in northern Australia is almost too good to be true, but the more I check out the little that is known the more certain that we need to take this report very seriously.

First of I sourced Google maps to take a satellite look at Arnhem Land. Reports suggest that the animal ranges throughout the region and even much farther afield. However, our conjecture regarding its primary prey tells us to look for a large riverine wetland that could be suitable for primary refugia.

The absolute last thing I expected to find was an Everglades like swamp, but it is there. I also found plenty of river valleys holding crocodile habitats. Take a look at it. This is straight out of Conan Doyle’s Lost world. It is big enough and it is wet enough and it has obviously been able to stay that way for millions of years. Until the sea level overran the coastal plains about 10,000 years ago, it was part of a large tropical ecosystem that clearly is connected in time to the cretaceous. This is one of its last surviving remnants.

This is the item out of wikipedia

Arafura Swamp

The Arafura Swamp is a large inland freshwater wetland in Arnhem Land, in the Top End of the Northern Territory of Australia. It is a near pristine floodplain with an area of 700 km2 that may expand to 1300 km2 by the end of the wet season, making it the largest wooded swamp in the Northern Territory and, possibly, in Australia. It has a strong seasonal variation in depth of water. The area is of great cultural significance to the Yolngu people, in particular the Ramingining community. It was the filming location for the film Ten Canoes
Geography and climate

The Arafura Swamp is a large and irregular floodplain surrounded by a low plateau 60–100 m in height, with prominent scarps to the east and west. The eastern scarp contains the Arafura Jungles site. It is laced with drainage channels and billabongs and forms a major flood-control and sedimentation basin for the Goyder-Glyde river system, with the main inflow coming from the Goyder and Gulbuwangay Rivers in the south, and with discharge northwards through the Glyde River into the Arafura Sea. It has a monsoonal tropical savanna climate with a mean annual rainfall of over 1000 mm, falling mostly from December to April. In dry years much of the swamp lacks free standing water during the dry season. The average annual increase in water depth over the wet season is nearly two metres, with refilling starting in January and reaching its greatest depth in April.

Flora and fauna

The Arafura Swamp contains 25 distinct plant communities, with over 100 species of grasses, herbs, aquatics, sedges and trees recorded. Most of the swamp is covered by low forest and woodland over grassland, with the dominant tree species being the paperbarks Melaleuca cajuputi and Melaleuca leucadendra.

The swamp is a major breeding area for Magpie Geese. Other abundant waterbirds include Wandering Whistling Ducks, Pacific Black Ducks and Green Pygmy Geese. There are breeding colonies of Royal Spoonbills, Little Pied and Little Black Cormorants, and Darters. Land adjacent to the swamp supports one of the largest breeding populations of the Hooded Parrot outside the Katherine area.

Large numbers of fruit bats feed and roost in the extensive paperbark forests. The Threadfin Rainbowfish, once known only from New Guinea and the Cape York Peninsula, has been discovered in the swamp. It is also an important breeding site for Freshwater and Saltwater Crocodiles.

Cultural use

Aboriginal people from the Ramingining community use the swamp for fishing, hunting and gathering, including harvesting the eggs of geese and crocodiles. The margins of the swamp are used for grazing livestock. The swamp is one of very few tropical wetlands in Australia continuing to be managed by Aboriginal people using traditional land management practices, including formal burning regimes. Traditional use of the swamp was studied by anthropologist Donald Thomson in the 1930s.
Much of the 2006 film Ten Canoes was filmed on location in the swamp with many of the actors deriving from the local community and speaking in Yolŋu Matha.


Here we are. We have a perfectly good swamp with an excellent supply of crocodiles for food. The range is ample enough to maintain a healthy breeding population. This story actually has an embarrassment of riches. I never expected to have a bona fide target area that was a gimme.

The animal is also clearly nocturnal, or he would have been encountered many times before now. This is surely a response to high daytime temperatures which makes the animal sluggish. It has a lot of meat in its lower body which surely assists it in moving around the swamp. However it is hardly fast moving and likely chooses to surprise prey. That means that it takes advantage of cover.

Reported kills of cattle and kangaroos would be opportunity kills. Its preferred target is still any of the thousands of crocodiles available who can be taken by the simple expedient of jumping on the croc’s back and tearing of its head.

It would be amusing it these animals are available to reintroduce to the croc infested waters of Africa, the Everglades and the Amazon. We would have to be very comfortable in their husbandry before we pursued that, but why not? These are important wetlands that are amenable to agricultural development and the infestation of crocs and alligators are a serious liability. The question of course is whether a theropod is even more of a liability.

I also wonder if what we view as a smaller version of Tyrannosaurus Rex is only the juvenile form of same. The reason that I ask that is that these dawn reptile families have shown amazing stability against speciation over millions of years. The croc is an excellent example of just that. Of course, I may be wrong, but these creatures have occupied a very specific tropical niche from the very beginning and they would be indistinguishable from their early members.

What this all means is that a proper effort needs to be mounted to this particular swamp and its environs. A careful biological inventory needs to be conducted and capture techniques need to be employed. I can think of several viable capture options to pursue and would expect success. The effort would need to be supported over a full year and include the filming of a documentary. This is fully justified because this is likely as close to a snapshot of the Cretaceous as we can clearly define on Earth. And yes, I would love to take on this project.

That is another reason to think about establishing additional refuges for the biome.

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