Once thought as the least evolved of the mammals that roam our world, new research shows that marsupial evolution might actually be further along than even humans. This old bias towards the creatures comes from many seeing them as the intermediate stage between egg-layers and placental mammals. However, as it turns out, marsupials have evolved more than any other mammal from their ancestral form.
This discovery is outlined in a new paper published in Current Biology. The researchers look at the developmental stages of 22 currently living species to help construct a timeline that best explains the changes that exist right now. From there, they used 3D micro-CT scans to reveal additional changes we didn’t know about before.
By looking at how marsupials compare to the common therian ancestor from 160 million years ago, researchers say skull development slowed and shifted in marsupials. Instead of how marsupials give birth – which many saw as lesser than placental births where gestation takes place for much longer – being simple, they found that it is actually a more specialized development type, thus showing how far marsupial evolution has come.
Additionally, they found that the way marsupials develop is actually far more changed from our common therian ancestor than the way that humans and other placental developing mammals have changed. As such, marsupial evolution has happened entirely differently than other mammals, possibly making them the most evolved mammals to walk the Earth.
However, the research is far from complete. The team was only able to look at 22 different species, which means additional research will need to be done in order to support the findings more drastically. There were also some limitations in how they estimated the ancestral state due to the lack of early examples of development in those creatures.
Still, it is an intriguing bit of research and one that definitely makes you scratch your head a bit, as many have believed that human evolution was the peak success of evolution and that humans were the center point for it. However, as the scientists note, that isn’t how evolution works. It applies to all things, not just humans, and marsupial evolution seems to have pulled ahead somehow.