THE history of humanity is getting more and more complicated. New discoveries are challenging our understanding of how we evolved and when we moved out of Africa.

New digs in Saudi Arabia have uncovered a cache of fossils buried within identifiable geological features.

One of the fossils is a homo sapiens finger bone.

It’s from a pointer finger (phalanx).

The others are from an assorted variety of animals.

According to research posted in the science journal Nature Ecology and Evolution, all have been placed in a context dated some 85,000-88,000 years ago.

It’s just one bone.

But its discovery suggests humanity’s first explorers stepped out of Africa and into the Arabian Peninsula some 20,000 years earlier than first thought.

The fossils were found in 2016 at Al Wusta in the An-Nafud desert, northern Saudi Arabia. It was the 3.2cm human finger bone, however, that drew all the attention.

It has since been undergoing examination to confirm its origins and age.

It was scanned with 3D laser imaging systems and compared to finger bones to a variety of hominins, including Neanderthals. It matched our own species — Homo Sapiens.

Uranium-series dating, where samples were taken to measure the ratios of radioactive elements, dated the fossil to 85,000 years ago. Its geological context, and the dating of the other fossils, supports this.

Back then, Saudi Arabia wasn’t the desert we know now.

The climate was different. It was moist. Humid.

The terrain was filled with open grasslands, and seasonal lakes.

“We have found 10,000 ancient lakes in Arabia,” says Michael Petraglia of the Max Planck Institute. “We have visited about 200, and about 80 perc ent have evidence of archaeology.”

Al Wusta was different in that it was likely to have been a permanent source of water.

To the boundary-pushing humans, it must have seemed rich and abundant.

So they settled there. Archaeologists have found hundreds of their stone tool fragments at the site.

Confirming that the occupants were humans, however, has not been easy.

The earliest reliable date from existing evidence is that homo sapiens left Africa some 60,000 years ago.

But the new finds — apart from the human finger bone — suggests expanding into new territories would not have been as difficult for them as initially believed.