Scientists use skulls to show how "Last Common Ancestor" between Homo sapiens and Neanderthals might have looked

This article originally appeared on Culture24.

Scientists aim to solve controversies surrounding human evolution and fill out blank fossil record

The last common ancestor between Homo sapiens and Neanderthals had a thick set brow and hints of the cheekbone indention which gives modern humans “more delicate” facial features, according to scientists who say the figure came from Africa around 700,000 years ago.

A set of 797 cranial “landmarks”, plotted on heads covering almost two million years of Homo history, show that both species may have converged in the ancestor’s skull during the Middle Pleistocene period.

The virtual fossil was created with artefacts including a 1.6 million-year-old Homo erectus fossil, Neanderthal heads found in Europe and 19th century skulls from Cambridge’s Duckworth collection.

Dr Aurélien Mounier, of Cambridge University’s Leverhulme Centre for Human Evolutionary Studies, says the aim has been to fill in the blank fossil record, find out what the common ancestor looked like and prove that rare fossil fragments came from the ancient ancestral population.

“Many controversies in human evolution arise from these uncertainties,” he says.

“We wanted to try an innovative solution to deal with the imperfections of the fossil record: a combination of 3D digital methods and statistical estimation techniques.

“This allowed us to predict mathematically and then recreate virtually skull fossils of the last common ancestor of modern humans and Neanderthals, using a simple and consensual ‘tree of life’ for the genus Homo.”

Each landmark contributed to the evolutionary picture, allowing researchers to feed a digitally-scanned modern skull into the timeline and warp it to fit the changing shape.

Watch a video about the skull scans



Previous DNA tests had suggested that the last ancestor lived around 300,000 years earlier.

While the population the split would have covered was also present across Eurasia, the new findings have concluded that its “most likely” origins were in Africa and that it was “probably” a member of the Homo heidelbergensis species, which was also present in Europe.

Dr Marta Mirazón Lahr, a fellow expert at the centre who is a leading author on evolution and cranial changes, says the higher rate of human morphing reflects “periods of major demographic change and genetic drift.”

“It is part of the history of a species that went from being a small population in Africa to more than seven billion people today,” she adds.

Changing human cranium

• The virtual 3D ancestral skull bears early hallmarks of both species. It shows the initial budding of what in Neanderthals would become the ‘occipital bun’: the prominent bulge at the back of the skull that contributed to elongated shape of a Neanderthal head.
  
  
• The face of the virtual ancestor shows hints of the the maxillia – the upper jaw and palate of the mouth - being ‘pneumatized’, meaning it had thicker bone and more air pockets, making the face of a Neanderthal protrude.
  
  
• Research from New York University, published last week, showed that bone deposits continued to build on the faces of Neanderthal children during the first years of their life.
  
  
• For their next project, Mounier and his colleagues have started working on a model of the last common ancestor of Homo and chimpanzees. They say the models could be used to test theories on horses and dinosaurs.

The results of the study are published in the Journal of Human Evolution.

What do you think? Leave a comment below.

© University of Cambridge

Three museums to discover stories of evolution in

National Museum of Scotland, Edinburgh
Until recently no fossil evidence had been found to explain how vertebrate life stepped from water to land, leading to a gap in our scientific knowledge of evolution. Known as Romer’s Gap, this mystery has been challenging palaeontologists for generations. However, after years of searching, the answers have begun to be unearthed. Find out more in the current exhibition, Fossil Hunters: Unearthing the Mystery of Life on Land. Until August 14 2016.

Great North Museum Hancock, Newcastle
Live animal tanks and aquaria are integrated into a major display where visitors can see wolf fish, pythons and lizards to name a few. Star objects include a full size model of an elephant, a great white shark, a virtual aquarium, live animal displays, a polar bear, a giraffe and moa skeleton.

Museum of Zoology, Cambridge
The museum's collections date back to 1814, and draw many of the earlier specimens from the great collecting expeditions of the 19th century, including Charles Darwin's 'Beagle' voyage. All major animal groups are represented, as well as a high proportion of scientifically important material such as types and holotypes, particularly noteworthy insect and mollusc material, and fine examples of extinct fauna such as the Great Auk, Thylacine, fossil tetrapods and giant marine reptiles.

Source: http://www.culture24.org.uk/science-and-nature/dinosaurs-and-fossils/art543328-fossil-homo-sapien-neanderthal-cambridge-duckworth