AUSTRALIA’S ANCIENT MEGAFAUNA
Long after the extinction of the dinosaurs, extraordinary species of giant beasts roamed the Earth, ruling the animal kingdom for hundreds of thousands of years. On the water locked land that is now Australia, a multitude of distinct megabeasts were able to evolve.
MEGA MAMMALS
- Diprotodon has entered the everyday lexicon as the largest marsupial that ever lived. It has been described as a giant wombat, but actually was not. That honor goes to Phascolonus, which lived alongside Diprotodon and was eight times as massive as the largest living wombat.
- The large marsupial Zygomaturus was restricted to south-eastern and south-western Australia, unlike its close relative the more widely ranging Diprotodon. This reflects the preference of Zygomaturus for lush, forested habitats, in contrast to the open plains and arid regions favored by Diprotodon.
- Thylacoleo has been called the marsupial lion; however, it was quite unrelated to true lions, having evolved from either possums or, incredibly, from koalas.
- Zaglossus hacketti, a sheep-sized echidna whose remains were discovered in Mammoth Cave in Western Australia, was probably the largest monotreme ever. Monotremes are mammals that lays eggs as opposed to giving birth to live young.
- During the Pleistocene period, the giant koala Phascolarctos stirtoni occupied the same arboreal niche as the modern koala. Phascolarctos stirtoni was about one third larger than its modern equivalent.
- The skull of the extinct kangaroo Simosthenurus occidentalis shows that unlike other kangaroos, its eyes were positioned more forward, giving it almost binocular vision.
- The red kangaroo (Macropus rufus) is thought to be the last remaining megafauna, though it is smaller today than it was thousands of years ago.
- Marsupials are notably less intelligent than placental mammals, a fact that is attributable in part to a simpler brain. Compared with that of placentals, the brain of marsupials differs markedly in both structure and bulk. Most notably it lacks a corpus callosum, the part of the placental brain that connects the two cerebral halves.
|
