Galadi+Speciosus

 ﻿ The Greater Bilby (Modern Animal)>> Commonly known by its Latin name //Galadi Speciosus// is believed to be a direct ancestor of the Greater Bilby; //Galadi// translating from the local language, Wanyi Aboriginal, as bandicoot or possum, S//peciosus// meaning ‘beautiful in appearance’ in Latin. The species relies on well preserved artefacts found in North West Queensland in Australia; three skulls that have been preserved as if they were from a modern or recent animal, as well as several maxillae and multiple single teeth. These artefacts have been dated back to as far as 20 million years old; however most revolve around the 18 million years old age.
 * Galadi Speciosus **

This specific genus was believed to more carnivorous than its descendant and scientists believe that it would have most likely devoured reptiles such as lizards, frogs, small possums, bandicoots and even birds, as well as larger insects, who made home of the rainforests in which //Galadi Speciosus// dwelled. Unlike the Greater Bilby, the Galadi relied more heavily on other animals as a source of food (although it was omnivorous), as well as having a bodily requirement of drinking water directly.

As the species fossils were found in North West Queensland in the soft uncompressed freshwater limestone of the area. Scientists suggest that the Galadi was a dominant hunter in the area, which after the supercontinent Gondwana split into several continents, was covered in dense rainforest. These forests were home to some of the world’s most diverse and interesting ecosystems at the time. Through the ages, this evidentially resulted in this specific part of Australia containing most of the world’s flora and fauna fossils of the ancient forests.



The climatic conditions in Northern Australia at the time could be described as increasingly tropical. This inference comes from the notion that at the time Australia was drifting slowly northward away from Antarctica. However, approximately 25 million years ago during the temporal time period known as the Oligocene Epoch, glacial ice began to cover much of Antarctica and the South Pole, which lead to the gradual replacement of rainforests by cooler woodlands in Australia.

Humans had not yet inhabited Australia, so there were no major threats to hinder the lifestyle of the bilby. However, an inference made by the scientists who studied the fossils suggest that due to the small size of the Galadi, threats and predators for this species could have included any larger carnivorous mammals or reptiles such as snakes.

Furthermore, animals which are proved to have inhabited the Riversleigh rainforest around 20 million years ago include the marsupials such as //Silvabestius, Neohelos ‘Giant Wombat’ and Yalkaparidon; //the reptile resembling a goanna known as the //Mekosuchine//; as well as birds such as the large //Pengana robertbolesi// and the Riversleigh rainforest cockatoo.

** ﻿ Scientific Classification ** ** ﻿ Kingdom: **Animalia  ** ﻿ Phylum: **Chordata  ** ﻿ Class: **Mammalia  ** ﻿ Infraclass: **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;"> Marsupialia  **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;"> ﻿ Order: **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">Peremelamorphia  **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;"> ﻿ Genus: **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">Galadi  **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;"> ﻿ Species: **//<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">Galadi Speciosus // ** Adaptations **


 * <span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">Structural adaptation 1: **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;"> Another interesting but dangerous structural adaptation that the Galadi developed in order to survive in the Australian environments in which they lived is their teeth structure. The Galadi is an omnivore, however unlike the Greater Bilby; this species was believed to be built to hunt vertebrates. Carnivores are armed with long canines and sharp incisors, whereas herbivores and omnivores have sharp incisors are well as strong molars to cut and grind the vegetation and small insects that are part of the animal’s diet. //Galadi Speciosus// is an omnivore with the features of all three. Large canines found on the fossil push scientists to describe this creature as a ‘pre sabre tooth bilby’, suggesting is viciousness in the name. The Galadi also has highly developed incisors and molars.

<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">This adaptation allows the diet of the Galadi to be expanded greatly, which means that this species was not forced to rely on any one food source. This adaptation proves extremely successful, and scientists are unsure as to why this adaptation was not passed on as it is a favourable trait. An environmental pressure that could have pushed for this is the seasonal changes in the environment in which this species of bilby resided. As winter came to Australia, much of the Galadi’s deciduous vegetative food source could have died out, pushing this species to hunt. Furthermore a dependence on one food source would have weakened the //Galadi Speciosus//.
 * <span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">Structural adaptation 2 **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">: Most species of bilby are regarded as quite small, and it is not expected that the head of an animal make up more than one third of the animals overall structural mass. However, //Galadi Speciosus// had an interesting head shape which allowed it to hunt animals that were up to two times larger than itself. The Galadi fossils found display large areas at the back of the jaw into which muscles were to fit. This large space suggests a powerful jaw. The Galadi’s powerful jaw allowed it to chew through the bones of its prey, eating whatever meat could be found on the bone as well as having the ability to get through thick hide or skin, as well as through tough vegetation. Another animal with a bone crushing jaw is the hyena.

<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">The environmental pressure that pushed for this adaptation to occur is most likely the fact that the food source adapted to have thicker hide, or the bones of the animal that the Galadi hunted became more calcium enriched and therefore tougher. This helped the animal survive as it meant that there were little or no limitations as to what the animal could eat. <span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">An environmental pressure for this adaptation could be that the timid bilby was not game enough to hunt for food, which could have in turn led to its extinction. This adaptation meant that although the Galadi was not fearless, it was a lot more confident and was therefore able to explore new parts of its habitat, giving it more food and living opportunities. Another pressure that pushed for the development of this adaptation could have been that the threat of predators to a meek animal was great, where as a more aggressive animal was more likely to win the fight. This could be compared to the process known as natural selection, whereby only the fittest of the species survive while the others die out.
 * <span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">Behavioural adaptation 1: **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;"> The Greater Bilby is described as a timid, skittish creature by those who encounter it. The Galadi, however, is compared to ‘a raging pit-bull’, which enforces the obvious characteristic differences between the two species. The aggressive nature of this animal could have had many positive and negative consequences. Negative consequences that could occur as a result of this behaviour are as extreme as the death of the animal as its instinct gets the better of it, when it tries to take on larger animals. However, this behavioural characteristic could also have positive repercussions such as a better chance of food especially when there is competition for meals, and the protection of offspring in and outside the burrow.
 * <span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">Behavioural adaptation 2: **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">The ancient bilby //Galadi Speciosus// had a similar digging style to that of [|rabbits]; a style that was not as developed as those of today’s modern bilbies. This species of marsupial dug their tunnels so that they went down into the earth in a diagonal fashion, where at the end a single chamber was built. This chamber was dug using the sharp claws and extremely powerful forelimbs of the Galadi. Perhaps one of the most interesting aspects of this species living conditions is where the animal chose to situate its burrow. The burrows of these creatures were often found hidden under trees, or tucked in between some kind of rock or barrier.

<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">This behavioural adaptation, specifically in relation to the selection of the whereabouts of the burrow, provided further protection and a cooler environment for this animal to inhabit. As the burrow went straight into the earth (unlike the Greater Bilby’s burrowing tunnels which curved in a spiral like shape), it was not uncommon for the sunlight to stream directly into the burrow. The use of trees and rocks as a surrounding blocked much of the sunlight from entering the burrow, in turn resulting in a cooler living environment. Furthermore these barriers could stop unwanted larger predators such as foxes, from entering the burrow and becoming a threat.

<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">The environmental pressure that could have pushed for this adaptation is obviously the intensity of the sun in the Australian climate in which the Galadi inhabited. The behavioural adaptation that meant that the animal burrowed around protection, allowed the species to live in its home during the day, without the threat of overheating. Also, it prevented predators from entering the home, as the entrance to the burrow was made smaller by these barriers.
 * <span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">Behavioural adaptation 3: **<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">A further adaptation inferred by the scientists who discovered the fossils of //Galadi// Speciosus is that this particular species lived a solitary lifestyle. Similar to the Greater Bilby, scientists believe that the Galadi only lived with other members of the species during mating, or when a mother was looking after her juveniles.

<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">This solitary lifestyle could have had both negative and positive impacts on the survival of the Galadi. A negative impact is that often for more defenceless animals, living in a pack or group provided a form of protection against predators- a defence mechanism that //Galadi Speciosus// could not make use of. However, this behavioural characteristic could also have helped it survive, as the animal felt no pressure to look after a group, they were able to move freely and not be tied down in a group environment, and there was less competition for things such as mating rights amongst males and females alike.

<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">One of the most likely reasons this behavioural characteristic helped the genus to survive was because they were able to do many things only a solitary animal would do; take on larger predators and act without hesitation due to lack of direct consequences on other animals. An environmental pressure that could have pushed for this adaptation to occur is the freedom of living by one’s self, the separation of animals by water or land masses or aggressive-territorial behaviour. The advantage of this for the Galadi is that it only had to find food for its self, and it’s juvenile (if the adult is female). ** ﻿ Extinction Pressure **

<span style="font-family: 'Georgia','serif'; font-size: 16px; line-height: 115%;">There are many reasons that give evidence as to exactly why the bilby //Galadi Speciosus// became extinct. Firstly, as Australia moves every increasingly northward, it becomes drier. Perhaps the Galadi could not adapt quickly enough to these drier conditions and therefore died out due to a lack of water. Unlike the Greater Bilby, the Galadi has no evident way of deducing water from its food. This may have also been the reason why the Greater Bilby surpassed the Galadi in the process of natural selection. Furthermore, //Galadi Speciosus// may have been wiped out during the mass extinction known as the Middle Miocene disruption, in which many terrestrial and aquatic life forms, who had not adapted to a cooler climate, were wiped out.

** Bibliography ** <span style="font-family: Georgia,serif; margin-left: 0.5in; text-indent: -0.5in;">Australian Museum. (n.d.). //Fossil Sites of Australia- Riversleigh//. Retrieved June 24, 2011, from Australian Museum Online2010: http://web1.stmaryssen-h.schools.nsw.edu.au/SMSHS/ricks%20sites/Biology%20web%20site/Pre_8_5_Evolution%20of%20Australian%20Biota/riversleigh%20fossils/Riversleigh%20fossils%202/riversleigh2.htm

<span style="font-family: Georgia,serif; margin-left: 0.5in; text-indent: -0.5in;">Baez, J. (2006, October 1). //Temperature//. Retrieved June 25, 2011, from Maths UCR: http://math.ucr.edu/home/baez/temperature/

<span style="font-family: Georgia,serif; margin-left: 0.5in; text-indent: -0.5in;">Beale, B. (2010, September 1). //Gentle Bilby had 'killer' ancestor//. Retrieved June 27, 2011, from PhysOrg: http://www.physorg.com/news202543156.html

<span style="font-family: Georgia,serif; margin-left: 0.5in; text-indent: -0.5in;">University of New South Wales. (2010, September 1). //Ancient skull reveals 'killer bilby'//. Retrieved June 26, 2011, from Acience Alert: http://www.sciencealert.com.au/news/20100209-21288.html

<span style="font-family: Georgia,serif; margin-left: 0.5in; text-indent: -0.5in;">Wet Tropics Management Authority. (2010). //The Evolution of the Wat Tropics of North Queensland//. Retrieved June 20, 2011, from Tourism Daintree: http://www.daintreevillage.asn.au/evolution.html

<span style="font-family: Georgia,serif; margin-left: 0.5in; text-indent: -0.5in;">Wikipedia. (2011, May 30). //Galadi//. Retrieved June 24, 2011, from Wikipedia: http://en.wikipedia.org/wiki/Galadi

<span style="font-family: Georgia,serif; margin-left: 0.5in; text-indent: -0.5in;">Young, E. (2010, September 7). //Carnivorous bilby fossil unearthed//. Retrieved June 25, 2011, from Australian Geographic: http://www.australiangeographic.com.au/journal/ancient-carnivorous-bilby-fossil-unearthed.htm