World’s earliest PRIMATE dating back almost 66 million years unearthed

Primate fossils dating back more than 66 million years are the earliest examples of our ancient ancestors, and could hold the key to understanding life after dinosaurs.  

Archaeologists from the University of Washington’s Burke Museum analysed several fossils of Purgatorius, the oldest members of the earliest-known primate species.

The team studied fossilised teeth from the Hell Creek area of northeastern Montana dating back about 65.9 million years – 139,000 years after the Cretaceous-Paleogene mass extinction event that wiped out 75% of life on Earth including the dinosaurs. 

The remains belong to a group that were the ancestors of all primates, finding they lived alongside the dinosaurs, rather than emerging after they died out.

These primates were able to thrive after the dinosaurs became extinct, and went on to spread and multiply, eventually leading to the emergence of modern humans. 

Shortly after the extinction of the dinosaurs, the earliest known archaic primates, including a new species, Purgatorius mckeeveri (foreground), quickly set themselves apart from their competition by specialising on an omnivorous diet including fruit found up in the trees

A team of 10 researchers studied several fossils of Purgatorius, the oldest genus in a group of the earliest-known primates called plesiadapiforms. 

These remarkable ancient mammals were small-bodied, and ate specialised diets of insects and fruits that varied across species. 

This discovery is central to primate ancestry and paints a picture of how life on land recovered after the mass extinction event – possibly caused by an asteroid. 

The event wiped out all dinosaurs (except for birds) and led to the rise of mammals.

Dr Gregory Wilson Mantilla, co-lead on the study said it was mind blowing to imagine and see the remains of our earliest archaic primate ancestors.

He said: ‘They were some of the first mammals to diversify in this new post-mass extinction world, taking advantage of the fruits and insects up in the forest canopy.’  

Mantilla from Burke Museum worked with Dr Stephen Chester of Brooklyn College and The Graduate Center, CUNY. 

‘This discovery is exciting because it represents the oldest dated occurrence of archaic primates in the fossil record,’ Chester said. 

‘It adds to our understanding of how the earliest primates separated themselves from their competitors following the demise of the dinosaurs.’ 

Fossils, including teeth, from the ancient mammal species helped researchers to pin their age to before the demise of the dinosaurs

Fossils, including teeth, from the ancient mammal species helped researchers to pin their age to before the demise of the dinosaurs

Study authors Gregory Wilson Mantilla and Stephen Chester search for fossils in Montana

Study authors Gregory Wilson Mantilla and Stephen Chester search for fossils in Montana

PURGATORIUS: OUR OLDEST PRIMATE ANCESTORS

Long before humans, apes, lemurs and gorillas, primates were small creatures feasting on fruit and insects.

Purgatorius is a genus of extinct species thought to be early primates.

They date back more than 65 million years and likely lived alongside the dinosaurs – at least for a short time.

After the mass extinction event that killed the dinosaurs mammals, including Purgatorius, went on to thrive by specialising in fruit and insects that survived the event. 

Based on the age of the fossils, about 65.9 million years, the team estimates that the ancestor of all primates likely emerged by the Late Cretaceous.

This means they lived alongside the dinosaurs, at least for a short period of time before they were wiped out, along with most life on Earth. 

The fossils include two species of Purgatorius – Purgatorius janisae and a new species described by the team called Purgatorius mckeeveri. 

Three of the teeth found have distinct features compared to any previously-known Purgatorius species and led to the description of the new species.

The new species Purgatorius mckeeveri is named after Frank McKeever, who was among the first residents of the area where the fossils were discovered. 

‘This was a really cool study to be a part of, particularly because it provides further evidence that the earliest primates originated before the extinction of non-avian dinosaurs,’ Co-author Brody Hovatter said. 

‘They became highly abundant within a million years after that extinction.’

‘This discovery is exciting because it represents the oldest dated occurrence of archaic primates in the fossil record,’ he added.

‘It adds to our understanding of how the earliest primates separated themselves from their competitors following the demise of the dinosaurs.’

They were prolific breeders, with researchers discovering that within a million years of arriving in what is now northwest Montana the species outstripped other native life and dominated the insect and fruit produce. 

The findings have been published in the journal Royal Society Open Science. 

WHY ARE NON-HUMAN PRIMATE NUMBERS DECLINING?

Behind the collapse in numbers is an increase in industrial agriculture, large-scale cattle ranching, logging, oil and gas drilling, mining, dam building and road construction. 

The illegal trade in bushmeat – killing apes and monkeys for their flesh – is also decimating the animals, as is changing climates and diseases spread from humans to apes. 

Growing trees to produce palm oil – used in many popular foods – is a particular threat to primates in Indonesia, as is mining for gold and sapphires in Madagascar.

With many species living in rainforests, the cutting down of millions of acres of forest to supply the increasing demand for timber or to clear land for agriculture is destroying their habitat and making populations more fragmented.