Well, it looks like we’ve been telling the wrong story about where modern mammals, including us humans, came from. For centuries, scientists have been convinced that our furry ancestors evolved in the Northern Hemisphere, but it turns out that might not be the case. A new study published in Alcheringa: An Australasian Journal of Palaeontology has found that the evolution of the earliest mammal ancestors, the ones that eventually led to humans, might have actually begun in the Southern Hemisphere.
Here’s the scoop: a team of researchers examined a bunch of tiny fossilized jawbones with distinctive back teeth and discovered that the oldest of these pre-dated those found in the North by 50 million years. These jawbones, which are about an inch or less and were found in countries like Argentina, India, Madagascar, and Australia, have special teeth called tribosphenic molars that can cut, crush, puncture, and grind plant food and insect prey.
Paleontologist Tim Flannery explained:
This new research has completely revised and turned on its head our understanding of early mammal evolution. It’s the most important piece of palaeontological research, from a global perspective that I’ve ever published, but it may take some time to find full acceptance among Northern Hemisphere researchers.
These jawbones represent the earliest ancestors of marsupials (like Australia’s cuddly koalas and wombats) and placentals (which include humans), and these ancestors migrated to Asia during the early Cretaceous period after evolving in Gondwana, the supercontinent that joined the southern continents together about 125 million years ago.
So, there you have it. It looks like our long-held beliefs about mammal evolution have been flipped on their head, and it’s time to rewrite some books.
Modern mammals are a group of animals that belong to the class Mammalia. They are characterized by several physical features that distinguish them from other animals, including the presence of mammary glands, which produce milk to nourish their young, and three middle ear bones, which are used for hearing. Modern mammals also have a unique type of teeth called heterodont dentition, which includes incisors, canines, premolars, and molars.