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.