What makes a kangaroo a kangaroo? You might immediately think of their ability to hop, but according to a study published in the Journal of Vertebrate Paleontology, ancient kangaroos weren’t be permitted to hop at all. This new research also makes up a particularly astonishing image: Millions of years, small-time ancestral kangaroos lived alongside crawling, fanged cousins.
Paleontologists at the University of Queensland have uncovered two brand-new species of extinct , non-hopping kangaroos within ancient Australian fossil accumulations. When they lived, the latter are approximately the size of a pademelon, a small, modern marsupial. The two new species, Cookeroo bulwidarri which lived 23 million years ago and Cookeroo hortusensis which lived 18 -2 0 million years ago were recognized as distinct species based on their unique skull and teeth arrangements.
Their skeletal chassis suggests that they were adapted to crawling on all fours, scooting around what used to be a densely forested region.Interestingly, this extinct crawling modification can also found in a variety of related animals, ones that these newly discovered animals would have co-existed with. This suggests that hopping had not yet progressed 18 million years ago.
The minuscule skull of the fangless C. hortusensis. Kaylene Butler et al ./ Journal of Vertebrate Paleontology
One of these co-existing swine was another ancient kangaroo ancestor: the Nambaroo was about the size of a small dog, and brandished large canine fangs. This animal, detected several years earlier, also had opposable toes and improbably flexible paws, which some researchers interpret as tree clambering adjustments.
Its strong forearms meant that it likely galloped around on all fours, hunting for meat. The Nambaroo, like other members of its radical includes the Balbaroo fangaroo was thought to have use its sharp fangs for display purposes exclusively, frightening off competitors and chasing mates.
All of these species, includes the new, fangless ones, lived in dense woodland, and so likely had a nutrition of fruit and fungi. As the forests handed practice to grassier, arid environs around 10 to 15 million years ago, moving around on all fours was no longer advantageous. But which of these scurrying marsupials are the direct ancestors of contemporary, bipedal, hop-skip kangaroos the fanged ones or the recently discovered species?
The fanged Nambaroo is thought to have lived around 25 million years ago; on the other hand, the two new species risen at the end of the Paleogene period around 23 million years ago, a hour of huge climate change. It was at this point that muggy, tropical situations were transitioning into groves and open grasslands.
Based on the ages of the fogies, it is clear that the two brand-new species were suited to foraging and prosper in these new milieu. On the other side, their older, fanged competitors could not keep up with the tempo of change, and they eventually died out. The reasons behind this continue uncertain, but it appears that these brand-new species were likely part of the group that eventually gave rise to modern kangaroos.