Laos Fossil Skull Indicates Rapid Human Migration

Most palaeontologists believe that hominids (that group of upright apes to which our own species H. sapiens belongs) evolved in Africa.  This is why that continent is often referred to as the “cradle of mankind”.  However, there is still debate as to how our species came to be so widespread.  Did modern humans evolve in Africa and then migrate across the world, or did more primitive hominids living elsewhere in the world evolve into more modern humans independently?

Human Skull Fossil

The discovery of a modern human skull (Homo sapiens), found in a mountainous region of northern Laos (south-east Asia), suggests that modern people were living in this part of the world 20,000 years earlier than previously thought.  This discovery, suggests that if modern humans evolved in Africa and then spread across the world, their migration was either much more rapid than previously thought, or the spread of modern humans began earlier than the current fossil evidence from Africa and the Arabian peninsula proposes.

Ancient Human Skull from Laos

Oldest Asian back-packer known to date.

Picture credit: PNAS (USA)

The two theories of modern human evolution are known as the “multi-regional hypothesis” and the  “out of Africa theory”.  The multi-regional hypothesis, supported by a minority of palaeoanthropologists argues that modern humans evolved gradually from different populations of an earlier hominid species Homo erectus.  Constant contact and interbreeding between these populations led to the evolution of similar traits and characteristics that came to define our species, H. sapiens.

The second theory, the “out of Africa” theory proposes that the origin of our species can be traced back to Africa.  Modern humans evolved in Africa and then they spread out and displaced other indigenous hominid populations around the world.  Genetic evidence supports this theory and most palaeoanthropologists tend to support this hypothesis over the “multi-regional” concept.

Modern Humans in Asia

However, this new discovery provides evidence that modern humans had reached south-east Asia around 63,000 years ago, much earlier than other human fossil finds have indicated.  If H. sapiens fossil discoveries are plotted onto a map of the world with their estimated ages, it reveals a fascinating pattern.  Generally, the earliest dated fossils are found in locations close to Africa.  The earliest modern human fossils found outside of Africa have been found at coastal locations such as Ksar Akil (Lebanon) and in Israel at Qafzeh and Skhul.  The further away from eastern Africa you travel, the more recent the fossils of modern humans.  For example, there is fossil evidence to indicate that modern humans crossed the Beringia Land Bridge from Siberia into North America as recently as 15,000 years ago.  This Laos skull, throws the timing of human migration into south-east Asia and into Australia out, with perhaps some populations reaching Australia earlier than the currently thought 45,000 years ago.

The skull was found in the Annamite Mountains, three years ago, but the scientific paper describing the find and detailing the methods used to estimate the age of the fossil has just been published in the academic journal “The Proceedings of the National Academy of Sciences – United States”.

Laura Shackelford (University of Illinois), one of the authors of the scientific paper commented that:

“There are other modern human fossils in China or in Island Southeast Asia that may be around the same age but they either are not well dated or they do not show definitively modern human features.  This skull is very well dated and shows very conclusive modern human features.”

Although there is an amount of archaeological and genetic data to suggest a rapid migration out of Africa for modern humans this skull provides the earliest evidence known of modern people living in south-east Asia.  The location of the fossil find also suggests that these human settlers did not migrate along coasts to the islands of the Pacific, inhabiting environments which were familiar to them.  This is evidence that some of the first settlers in Asia were prepared to explore and inhabit environments that were very alien to them.

Dr Shackelford went on to add:

“This fossil find indicates that the migration out of Africa and into east and Southeast Asia occurred at a relatively rapid rate, and that, once there, modern humans weren’t limited to environments that they had previously experienced.  We now have the fossil evidence to prove that they were there long before we thought they were there.”

No other remains or artefacts such as stone tools were found in association with the skull material so the scientists believe that the bone was probably washed into the cave.  The cave site was probably not inhabited or used as a burial chamber.  The fossil was excavated from a layer of strata located 2.5 metres below the floor of the cave, radiocarbon tests and luminescence techniques indicate that the sediment is between 46,000 and 51,000 years old, but uranium/thorium degredation studies place the date of the skull at around 63,000 years.

For models and replicas of hominins and prehistoric creatures: Hominins and Prehistoric Animal Models (Wild Safari).

This modern human probably came across a much more primitive hominid, very different in appearance to modern people – “Upright Man” –Homo erectus.  It is very likely that H. erectus evolved in Africa and that in the 2 million years or so that this species has existed, it too migrated “out of Africa”, spreading as far as south-east Asia.  H. erectus may have been established in Asia for many hundreds of thousands of years before the arrival of modern humans.

The story of human evolution is very complicated, fossil evidence is fragmentary and the relationships between the various species of hominids that lived in Africa is difficult to interpret.  Recently, scientists uncovered evidence to suggest that as recently as two million years ago at least three species of hominid lived together in eastern Africa.

To read more about these fossil discoveries: Three of a Kind from Lake Turkana.

At Least Three species of Hominid Co-Existed in Kenya Two Million Years Ago

Palaeoanthropologists have identified fossil hominid material in eastern Africa (Lake Turkana), that indicates that around two million years ago there were at least three types of human-like creature co-existing.  In new research published this week in the academic journal “Nature”, the research team have declared that at least three species from the mankind family tree lived in the same part of the world during the Late Pliocene Epoch.  One of these species, Homo erectus was probably part of that branch of the hominid family tree that would eventually lead to the evolution of our own species, H. sapiens.  The other two species are believed not to be direct ancestors of more modern humans and they may have become extinct, effectively ending their role in hominid evolution and development.

Scientists Explore the Extensive Sediments around Lake Turkana

Tracing human origins.

Picture credit: Mike Hettwer

Homo erectus

H. erectus, known as “upright man” due to his more human posture and gait was the first widespread human species.  For many years, palaeontologists thought that this particular species of early hominid evolved in Asia.  Scientists such as Eugene Dubois, a Dutch anatomist and anthropologist, believed that our ancestors evolved in Asia not Africa.  In 1889 he led an expedition to what is now known as Indonesia to search for fossil evidence to support his theory.  He found elements from a skull and some limb bones and named a new species of hominid Pithecanthropus erectus.  Scientists now believe that these bones represent Homo erectus and this hominid, with perhaps a brain size about three quarters the size of our own species, evolved in Africa before migrating eastwards across the Straits of Arabia into Asia and eventually into the islands of the Pacific.  With tool making skills and a mastery of fire; this human species was incredibly successful and not only have fossils been found in places many thousands of miles apart, the dates of these fossils show that this species has also persisted the longest in the human evolutionary story.  Having evolved approximately 2.2 million years ago, H. erectus survived until at least 250,000 years ago and some scientists believe that the last of this type of human actually went extinct in the very Late Pleistocene Epoch, around 50,000 years ago.

Although the fossil record is far from complete, it seems that H. erectus may have given rise to later types of hominid including the direct, common ancestor of both the Neanderthals (H. neanderthalensis) and our own species.

Lake Turkana

The other two species of early hominid found in the same layers of Lake Turkana sediment represent “evolutionary dead ends” according to the scientists.  The fossil discoveries may help to solve a forty year mystery concerning skull material found in the same part of Kenya that has caused considerable debate amongst palaeoanthropologists.  The fossil beds around Lake Turkana are  referred to as the “cradle of mankind” due to the amount of early Homo fossil specimens that have been found.

Three new hominid fossils, bones that make up part of the face, a near complete upper jaw with cheek teeth and fragments from a lower jaw excavated from a dig site to the east of Lake Turkana, appear to confirm that skull material found in the same area forty years earlier is indeed a separate species of early human.

In 1972, parts of a strange, human-like skull with a flat face was unearthed.  Calculations made regarding the size of the brain suggested that this creature had a brain size of around 750 cubic centimetres, much larger than Australopithecines and this evidence convinced many scientists that this was definitely an early member of the human family tree.  It was assigned to the species Homo habilis.  Scientists had no real idea what the skull of H. habilis looked like, as at the time very little skull material had not been discovered, so here was a convenient way of putting a “face” to an early member of the hominid family.  The skull material (KNM-ER 1470, referred to as 1470 for short), caused a great deal of debate amongst researchers.  Subsequent fossil finds showed that this skull was different from other material assigned to H. habilis and it was proposed that this skull was a male of the species and the other material represented females.  If this was the case, then the size difference between males and females of the species H. habilis was the greatest in all the primates including the modern gorilla.  Other scientists assigned this fossil to another species of early human – Homo rudolfensis.

Computer Image Showing Skull 1470 and the New Fossil Discoveries Combined

Say hello to H. rudolfensis.

Picture credit: Fred Spoor

A photographic reconstruction shows the KNM-ER 1470 cranium, discovered in 1972, combined with a new lower jaw KNM-ER 60000; both are thought to belong to the same species.  The lower jaw is shown as a photographic reconstruction, and the cranium is based on a computed tomography scan.  This is the first image of its kind taken of the “third” Lake Turkana hominid – Homo rudolfensis.

Skull 1470

Working out what the skull known as 1470 represented was proving controversial, no flat-faced skull material from the same sediments had been found and the lack of teeth and jaw bones made identification and placement in the human family tree extremely difficult.  However, these three new fossils, excavated in the area between 2007 and 2009 confirm the existence of a third, large-brained hominid that lived alongside H. erectus and H. habilis.  All these fossils were found within seven miles of each other and have been dated between 1.78 and 1.95 million years.

The Famous Lake Turkana Skull (KNM-ER 1470)

An early human face – skull 1470.

Commenting on the significance of the new fossil finds, Dr Meave Leakey, co-leader of the Koobi Fora Research Project in Kenya stated:

“For the past 40 years we have looked long and hard in the vast expanse of sediments around Lake Turkana for fossils that confirm the unique features of 1470’s face and show us what its teeth and lower jaw would have looked like.  At last we have some answers.”

The bones that make up a flat face (KNM-ER 62000) are very similar to those of KNM-ER 1470, proving that the 1972 fossil discovery was not an over-sized example of a male H. habilis.  The beautifully preserved upper jaw with most of its cheek teeth still in situ has made it possible for the research team to infer the type of lower jaw that would have fitted the skull known as 1470.

Co-author of the academic paper and leader of the scientific analysis, Professor Fred Spoor, from University College London (United Kingdom), stated: “Combined, the three new fossils give a much clearer picture of what 1470 looked like.  As a result, it is now clear that two species of early Homo lived alongside Homo erectus.  The new fossils will greatly help in unravelling how our branch of human evolution first emerged and flourished almost two million years ago.”

These fossil finds indicate that the evolution of our own species was not just a straight forward, linear progression.  On the plains of eastern Africa around two million years ago, there seems to have been a number of hominid evolutionary experiments going on with a number of different species co-existing and probably competing with each other for food and other resources.  Intense competition may well have acted as an “evolutionary accelerator”, providing a kick start to the evolution and development of our own part of the human family tree.  At least three species of hominid lived in this part of the world, H. habilis, H. erectus and H. rudolfensis.

For models and replicas of ancient hominids including H. erectus (whilst stocks last): Wild Safari Ancient Figures and Models.

Aerial Acrobat of the Jurassic

The  lithographic limestone beds of Solnhofen in southern Germany are famous for their Jurassic vertebrate fossils.  Scientists have studied these  quarries for more than two hundred years and as the limestone is no longer commercially quarried so palaeontologists are usually left to themselves to search amongst the finely grained limestone layers, separately the layers like opening the pages of a book in the hope of finding new fossil material.  Every once in a while, one of the fossils found, beautifully preserved in the fine limestone beds, provides scientists with an intriguing mystery.  A little fossil of a pterosaur, a flying reptile, once thought to represent a juvenile Rhamphorhynchus has been re-examined and a research team have discovered that this specimen represents an entirely new genus and it might have been a spectacular aerial acrobat as well!

The Solnhofen deposits were laid down in a shallow, still lagoon.  They have provided palaeontologists with evidence of over fifty fish species, numerous plant fossils and many different types of invertebrate.  The most famous fossils found in these strata are those of the early bird Archaeopteryx (A. lithographica).  However, this area has also provided many hundreds of pterosaur specimens.  Pterosaurs are not closely related to birds and they are not dinosaurs, although they are members of the reptilian clade known as the Archosauria, something which they do have in common with the dinosaurs.

Two type of pterosaur are known from these Upper Jurassic deposits, short-tailed pterodactyloids and long-tailed rhamphorhynchoids.  These fossils of flying reptiles from Germany have formed the foundation as to how palaeontologists classify the Pterosauria.  However, very few actual species of flying reptile have been described from the Solnhofen material, despite the hundreds of pterosaur fossils found.  It seems that Rhamphorhynchus spp. and the short-tailed Pterodactylus spp. were the dominant types, but a closer examination of what was thought to be a juvenile Rhamphorhynchus has led to scientists identifying a new species.

Manoeuvrable Pterosaur Genus

A fossil specimen, nearly complete and like many of the flying reptiles from these deposits, beautifully preserved, has been identified as a new type of Late Jurassic pterosaur.  Although clearly closely related to Rhamphorhynchus and definitely a member of the rhamphorhynchoids, this new species has fewer teeth and a more flexible tail than the long-tailed pterosaur genus known as Rhamphorhynchus.  Even more remarkably, the fourth bone of the finger that supports the skin membrane that makes up the wing was  curved.  The distal wing finger phalanges of both wings curved outwards. This distinguishes this type of pterosaur from all the others previously described, a new genus has been assigned – Bellubrunnus and a formal scientific name for this flying reptile has been established as Bellubrunnus rothgaenger.  The genus name translates as Brunn beauty, to honour the German quarry where the fossil was found, the species name acknowledges the amateur fossil collector who first unearthed this specimen.

Aerial Master?  An Illustration of Bellubrunnus rothgaenger

A highly manoeuvrable pterosaur.

Picture credit: Matt Van Rooijen

Bellubrunnus rothgaenger

Although the skull is quite badly crushed, the international team of palaeontologists who studied this fossil are convinced that the curved wing finger phalanges are not the result of distortion or compression. Both of the distal wing bones (one in each wing) are curved to the same degree.  This means that the aerodynamic properties of the leading edge of the wings of this creature would have been different from all other pterosaurs known to science.

At just fourteen centimetres long, the fossil material looked relatively unimpressive and indistinct from so many other Rhamphorhynchus fossils that had been found in the area before.  It was the fossilised remains of a juvenile flying reptile but it has always been assumed it was an example of a Rhamphorhynchus species.  However, once the prepared specimen had been viewed under ultra-violet light a lot more detail in the fossil material could be observed.

Right distal wing of the Specimen under UV Light Showing the Pronounced Curvature 

Curved wing pterosaur.

Picture credit: PLoS One

The scale bar in the picture represents 2 cm, the key is as follows: wpx refer to the wing phalanx bones, the fourth being clearly curved in this photograph.  The initials fb refer to the fibula (leg bone) and cdv indicate caudal vertebrae (tail bones).

The strange wings of this reptile, distinguish it from any other flying vertebrate.  The shape of the wings would have made powered flight somewhat more difficult but the shape would have allowed this animal to turn and dart about very quickly.  It was perhaps, the pterosaur equivalent of a stunt aeroplane.  Being more manoeuvrable may have assisted this flying reptile which probably grew to be the size of a Magpie.  It would have helped it to twist and turn in the air and snatch up insects as it flew.

To view models and replicas of flying reptiles and other prehistoric creatures: Flying Reptiles and Other Prehistoric Creatures.

The actual fossil was found in strata that is older than the main Solnhofen deposits, this site is still being explored and the research team are optimistic that more fossils of strange pterosaurs may be discovered.

The scientific paper: “A New Non-Pterodactyloid Pterosaur from the Late Jurassic of Southern Germany” by David W. E. Hone, Helmut Tischlinger, Eberhard Frey and Martin Röper published in PLoS One.