Humans coexisted with dinosaurs for a short time

A new study has decided that the ancestors of today's humans coexisted with dinosaurs for a short time. A discussion about this topic has been ongoing for a long time. The argument was that the mass extinction event that wiped out the dinosaurs took place before humans evolved but that assessment appears to have been overridden by this new study.

Image: MikeB

A team of palaeobiologists employed statistical analysis of fossil records to conclude that placental mammals originated before the mass extinction event which was the impact of a large asteroid into the earth in the area of the Gulf of Mexico as I recall.

It's believed that after the asteroid impact placental mammals diversified and evolved rapidly perhaps facilitated by the loss of competition from dinosaurs.

The lead author is Emily Carlisle of Bristol's School of Earth Sciences who said:

'We pulled together thousands of fossils of placental mammals and were able to see the patterns of origination and extinction of the different groups. Based on this, we could estimate when placental mammals evolved. Unfortunately, we don't know what our placental mammal ancestors would have looked like back then. Many of the earliest fossils of placental mammals are quite small creatures such as Purgatorius – an early ancestor of primates – which was a small burrowing creature a bit like a tree shrew. 'So, it's likely that many of our ancestors were small and squirrely."

The study's co-author, Daniele Silvestro, of the University of Fribourg, added:

"The model we used estimates origination ages based on when lineages first appear in the fossil record and the pattern of species diversity through time for the lineage."

Up until the research fossils of placental mammals had only been found in rocks longer than 66 million years old which is when the asteroid hit the planet.

Comment: the research conjures up imagery of early humans fighting with dinosaurs. My mind goes to the Jurassic Park films. It appears that something similar may actually have happened.

Note: the first true cat species first evolved around 25 million years ago which was well after the dinosaurs had become extinct.