Large Orbits = Large Eyes = Less Brain Space Dedicated to Higher Functions Therefore Neanderthal Extinction

Adapted to living “up north” when compared to their close relatives the Homo sapiens may have led to the demise of the Neanderthals according to a new study published in the academic journal “The Proceedings of the Royal Society B (Biology)”.

Neanderthals

A study of the size of the orbit (eye socket) in Neanderthal skulls indicates that these hominids had larger eyes than our own species, perhaps an adaptation to the shorter day length of northern latitudes where Neanderthals lived.  The long, dark European and near eastern Asian nights may have inadvertently led to the eventual extinction of the Neanderthals, a species of hominid believed to be most closely related to ourselves.

Looking at the Demise of the Neanderthals

Seeing off the Neanderthals.

Most palaeoanthropologists believe that H. sapiens and H. neanderthalensis shared a common ancestor (Homo heidelbergensis).  The Neanderthals thrived in Europe and they are the best known of all the fossil hominids, with fossils having been found in much of Europe and into the near east.  The Neanderthals are believed to have evolved around 350,000 years ago and are thought to have persisted until around 28,000 years ago (although recent studies have suggested that Neanderthals may not have survived until as recently as 30,000 years ago).

Highly Intelligent Hominids

If these sophisticated and highly intelligent hominids had large eyes, than more of their brain space would have been dedicated to processing optical information and therefore, perhaps, less of their brain volume could be dedicated to higher functions such as social interaction, communication, thinking and planning.

In contrast, the larger frontal brain portions of our own species allowed us to create clothing sewn together through the use of cleverly fashioned bone needles, better than the clothing and simple fur wraps worn by Neanderthals (we think).  Larger anterior portions of our brain may have helped us to develop wider social networks, a bigger circle of friends to help us when times were hard.

The British research team considered the idea that as the ancestors of Neanderthals left Africa and moved into higher latitudes, so they had to adapt to longer, darker nights and much shorter day lengths so typical of living in the United Kingdom today.  This resulted in a greater portion of the posterior part of the brain being dedicated to processing visual data.

The Latitude is Significant

For those hominids that remained in Africa (the ancestors of our own species), they lived in a much brighter environment with long, sunny days with a rapid deterioration of daylight and a brief dusk period, so typical of living in parts of the world much closer to the Equator.

PhD student Eiluned Pearce of the Institute of Cognitive and Evolutionary Anthropology (Oxford University) examined the skulls of thirty-two specimens of H. sapiens and thirteen specimens of H. neanderthalensis.  She found that the Neanderthal skulls had significantly larger orbits.  The eye sockets were larger by an average of 0.6cm when measured from top to the bottom.  In evolutionary terms, this difference, not recognised until now as a morphological difference between type specimens of these two species of humans, may have been enough for the Neanderthals to dedicate more of the brain’s processing power to analyse, interpret and process visual data.

Commenting on the significance of her research, Ms Pearce stated:

“Since Neanderthals evolved at higher latitudes, more of the Neanderthal brain would have been dedicated to vision and body control, leaving less brain to deal with other functions like social networking.”

The Neanderthals were very well adapted to living in a cold, harsh climate, much better than our own species.  However, scientists have puzzled over the reasons for the demise of the Neanderthals.  They seem to have co-existed with modern humans in some parts of their habitat for a few thousand years, but the Neanderthals did eventually become extinct, leaving modern humans to ponder over the reasons for their decline and eventual extinction.

The more visually-focused brain structure might have affected the Neanderthal’s ability to innovate and to adapt to changing climatic conditions.

Neanderthals – Extremely Well Adapted to their Environment

Did the large eyes of Neanderthals eventually lead to their extinction?

Picture credit: Everything Dinosaur

The picture (above) shows a Bullyland Neanderthal model.  To view the range of Bullyland hominid figures (whilst stocks last): Bullyland Prehistoric World Models.

Theories to Explain Neanderthal Extinction

A spokesperson from Everything Dinosaur stated that a number of theories had been advanced over recent years to help explain the extinction of the Neanderthals and the survival of H. sapiens.  Although, Neanderthals may have had a slightly larger cranial capacity when compared to our own species, their brains may have been “wired” differently.  Smaller family groups, shorter childhoods and a greater reliance on hunting megaherbivores may have all been contributory factors that led to the decline and eventual extinction of this species of hominid.

The scientific paper: “New insights into differences in brain organization between Neanderthals and anatomically modern humans” by Eiluned Pearce, Chris Stringer and R. I. M. Dunbar published in the Proceedings of the Royal Society B.

Sauropods Nesting in the Same Location for Millions of Years

A team of palaeontologists have documented a remarkable Upper Cretaceous fossil site in Catalonia (Spain) and have discovered that this location was a nesting ground for many types of Late Cretaceous sauropods,  At least four types of long-necked dinosaur eggs have been identified and from the study, published as an academic paper, it seems that the herbivorous megafauna of this part of Catalonia some 70 million years ago was very similar to the megafauna to be found in southern France during the Late Cretaceous.

Dinosaur Eggs

Scientists from the Miquel Crusafont Catalan Palaeontology Institute mapped the exposed Upper Cretaceous sediments in the Coll de Nargó palaeontological site (close to the village of the same name), in the western Catalonian province of Lleida.  Up until this new study, only one type of sauropod egg, that of a titanosaur had been recorded in this region.  This dinosaur is known as Megaloolithus siruguei, eggs attributed to this titanosaur species have been found in at least nine horizons in the Tremp geological formation in this part of the world.  Average number of eggs laid per nest seems to be around 25 but a number of locations have been extensively eroded and Cenozoic plate movements has distorted a number of egg fossil bearing locations so pinning down the average size of a clutch of dinosaur eggs is very difficult.

A Typical Late Cretaceous Titanosaur from Europe (Ampelosaurus)

A typical European titanosaur from the Late Cretaceous.

Picture credit: Everything Dinosaur

The picture above shows an illustration of a typical European titanosaurid dinosaur from the Late Cretaceous – Ampelosaurus.  CollectA have made a figure of this titanosaur, it resides within the CollectA Age of Dinosaurs – Popular model range.

CollectA Age of Dinosaurs – Popular: CollectA Popular Models (Age of Dinosaurs).

A Detailed Analysis

After completing a detailed analysis of more than 25 different fossil bearing horizons in the Tremp Formation, the palaeontologists were able to conclude that there is evidence to support that at least four other types of sauropod used this area as a nesting site.  Scientists have speculated that these large herbivores probably lived in herds and moved around extensively in search of food resources to satisfy their enormous appetites.  It is likely that these reptiles migrated annually to favourite nesting grounds just like many birds and turtles do today.

Lead author of this new research, Albert García Sellés (Miquel Crusafont Catalan Palaeontology Institute) stated that:

“Eggshells eggs and nests were found in abundance and they all belong to dinosaurs, sauropods in particular.  Up until now, only one type of dinosaur egg had been documented at this location, but now we have evidence to suggest four different types of dinosaur.”

Identifying Species

Identifying species of prehistoric animals from just remains of eggshells (and possibly embryos within the fossilised eggs), is referred to as analysing oospecies (working out the phylogenetic relationships between species – a study of ootaxa).  Scientists are attempting to set up the evolutionary relationships between the animals that produced the eggs.  Their work is complicated due to the seismic shifts in the sediments that once were deposited in a sequence of strata linking southern France and northern Spain, before the uplifting of the Pyrenees distorted the geological formations.

The additional oospecies named so far are Megaloolithus aureliensis, Megaloolithus baghensis and in the sister taxa Cairanoolithus roussetensis.

A Museum Exhibit Showing Titanosaur Eggs (Hypselosaurus)

An example of titanosaur fossil eggs.

Picture credit: Everything Dinosaur

The Tremp Formation

The strata that make up the Tremp Formation and other adjacent fossil bearing sediments were laid down in terrestrial environments. Although the team can estimate the relative age of the various fossil bearing horizons based on their stratigraphic sequence, the lack of zone fossils, otherwise known as guide fossils, is hampering their efforts to determine the absolute age of the strata and thus, the age of the fossils deposited therein.   In marine sediments for example, small creatures with hard shells such as gastropods, or ammonites can act as biozone markers.  These fossils are relatively abundant, distinct in appearance and they represent relatively rapidly evolving groups – ideal for acting as characteristic zone fossils to help identify the age of rock strata.

Different Types of Eggs

However, it has been noted that the different types of eggs (the oospecies) are located at very specific horizons.  This has permitted the palaeontologists to develop a better understanding of the chronological age of each of the fossil bearing layers of rock.  As a result, the scientists have determined that the rocks in this region represent a period in Earth’s history from 71 million years ago to approximately 66 million years ago (Maastrichtian faunal stage).

The fossilised eggs could contain clues to environmental changes that may have had a bearing on the mass extinction event that took place around 65-66 million years ago.  This location is very significant to European palaeontologists as it provides a window into the very last days of the dinosaurs.  It also shows that the megafauna in northern Spain was very similar to that of southern France during this time in the Late Cretaceous of Europe.

Nesting Colonies

In addition, the great volume of fossilised eggs and their spread across different stratigraphic horizons provides the scientists with very strong evidence to suggest that titanosaurs used this area of Spain as a nesting site for millions of years.  The presence of various oospecies at the same horizon also suggests that different species of titanosaur shared the same nesting area, perhaps in a similar way to many extant sea-birds sharing nesting colonies today.

Fossil strata containing evidence of dinosaur eggs and nests within the Tremp Formation were once part of a continuous low-lying basin that extended for hundreds of miles.  However, the collision of the Iberian and the European plates which began at the end of the Cretaceous and extended into the Oligocene Epoch led to extensive uplifting and the creation of the mountain range that now divides Spain and France – the Pyrenees.

University of Manchester Team Helps Identify Pliocene Camel Bones from the High Arctic

They may be known as “ships of the desert” and very well adapted to extremely arid environments but the evolutionary history of camels and their close relatives may have their origins in anything but desert habitats.   A University of Manchester team has been assisting a group of Canadian scientists helping to identify a series of fossilised bone fragments found in the High Arctic region of Canada.  The pieces of bone are from a species of giant camel, one that was quite at home in a habitat that was over 79 degrees latitude north, although during the past, when this ruminant roamed, the climate was generally a little warmer than the High Arctic of today.

Giant Camel

The fossilised remains of the camel were discovered in a Pliocene aged deposit located near Strathcona Fiord on Ellesmere Island.  The fossil site known as the Fyles Leaf Bed site has provided palaeontologists with an insight into life in this part of the world around 3.5 million years ago.  Although there may be only one type of woody tree native to Ellesmere Island today (a type of willow),  Ellesmere Island during the Piazencian faunal stage of the Pliocene, in the periods when ice sheets retreated, was a largely arboreal environment dominated by alder, birch and larches.  Sharing this woodland world with the camels were bears, beavers, badgers, rabbits, deer and rodents.

Members of the Research Team Hiking up to the Fossil Site

Team members trek up the slopes on Ellesmere Island to the fossil site.

Picture credit: University of Manchester

An Artiodactyl

Camels belong to a group of mammals known as the Artiodactyls (even-toed hooves).  The first camels are believed to have evolved in the Eocene Epoch, around 55 million years ago and over one hundred fossil species have been identified and named, although the Ellesmere Island discovery represents the furthest north any camel fossils have been discovered to date.

Dr Natalia Rybczynski Carefully Removes a Bone Fragment from the Scree Slope

Carefully removing a fragment of bone.

Picture credit: University of Manchester

Although extant camels are strongly associated with desert environments, these ruminants were much more abundant in grassland and woodland habitats.  Two groups of Artiodactyls (camels and bovoids such as cows) evolved a special way of digesting tough, fibrous plant material – rumination.  Once swallowed, food enters the first of three or four stomachs in the animal.  It is regurgitated and chewed a second time, this is known as chewing the cud.  Thus the plant material is subjected to two physical breakdown processes and these physical/mechanical processes are aided by micro-organisms that inhabit the digestive tract of the ruminant and assist in the chemical breakdown of the plant material, including the cellulose.  The micro-organisms live in a symbiotic relationship with their hosts.

Efficient Processors of Plant Material

Importantly, ruminants such as camels recycle urea, one of the body’s waste products, this is used to help nourish the micro-organisms living in the gut.  As a result of this urea recycling less urine is produced and less water wasted.  This adaptation has enabled animals such as camels to survive in very dry environments such as deserts.  However, as efficient processors of plant material with an ability not to waste too much water, these adaptations gave camels an ability to survive in other habitats that were arid and dry, such as those to be found a high latitudes.

Spotting the Remains of a Prehistoric Camel Can be Quite Difficult

Camel bone fragment in situ.

Picture credit: University of Manchester

“Collagen Fingerprinting”

The Canadian research team were unsure of the identity of the fossilised bone, which is believed to represent a portion of a tibia (limb bone).  They approached Dr Mike Buckley from the Institute of Biotechnology at Manchester University for assistance as Dr Buckley and his colleagues have developed a new way of pinning down the type of animal from bone evidence.  The technique is called “collagen fingerprinting”, minute amounts of collagen, the main protein constituent of bone had been preserved in the fossils.

By extracting a portion of the preserved collagen, the Manchester University team were able to identify unique chemical markers in the peptides (chains of amino acids) that are present in collagen.  These markers provided the researchers with the unique “fingerprint” that identified the bone pieces as being from an extinct type of camel.

Dr Mike Buckley Carries out the Test for Peptides in the Collagen Samples

Collagen testing.

Picture credit: University of Manchester

Once the data had been established, it was simply a case of using results on tests from extant and known extinct animals to find the closest match.  Thirty-seven extant mammal profiles were examined as well as data from the study of an extinct type of giant camel, whose fossilised remains had been found in the Yukon.  The analysis showed that the 3.5 million year old specimen closely matched the data from a modern Dromedary camel, as well as the Ice Age camel remains found in the Yukon.  Using this information, the Canadian team were able to report that the fragments of bone represented a species of giant camel that lived as far north as Ellesmere Island.

A Large Species of Camel

The scientists know that this is a very large species, much bigger than today’s extant Dromedaries as the bone fragments represent a tibia that is nearly a third bigger in the fossil specimen when compared to the tibia in modern-day Dromedaries.  These delicate fragments are currently being stored at the Canadian Museum of Nature’s research and collections facility in Gatineau (Quebec Province).

Dr Natalia Rybczynski of the Department of Palaeobiology (Canadian Museum of Nature), stated that this was an important fossil discovery:

“These bones represent the first evidence of camels living in the High Arctic region.  It extends the previous range of camels in North America northward by about 1,200 kilometres, and suggests that the lineage that gave rise to modern camels may have been originally adapted to living in an Arctic forest environment.”

Conducting an Analysis

The University of Manchester’s Dr Roy Wogelius (School of Earth, Atmospheric and Environmental Sciences) was able to conduct an analysis on the mineral content of the fossilised bone fragments.  His research suggests that it was a combination of the way in which the fossils were permineralised along with the very cold temperatures in that region that permitted the ancient organic remains to be preserved for over three million years.  This is a remarkable discovery, finding bone from the Mid Pliocene that can still yield protein data.

There has been much debate recently over the ability of organic traces to remain viable in the fossil record.  For example, recent research on extinct Moas from New Zealand provided an insight into the proposed half-life of DNA.

To read more about this research: Controversial Research Proposed Half-Life of DNA.

Dr Buckley commented that this was the first time that collagen had been extracted from such extremely old animal remains.  Exclaiming that the project had been a particularly exciting one to work on he was delighted that the type of animal had been identified from the “collagen fingerprinting” technique.

The  Fossilised Camel Bone Fragments (Tibia)

The fragments of fossilised camel bone.

Picture credit: University of Manchester

This research has implications for our understanding of the evolution of the camel clade.  Dr Rybczynski stated that this discovery sheds new light on the evolution of extant camels, perhaps suggesting that primitive camels first evolved in North America.  Specialisations seen in today’s camels such as an ability to store fat, to survive arid conditions and their broad, two-toed feet may be adaptations for living in a dry, polar habitat.