New Fossil Study May Lead to the Human Family Tree Being Simplified

A team of international scientists studying a series of hominin remains that date back some 1.8 million years, have concluded that the fossils. although showing a degree of variation, do all represent a single human species.  The team’s findings could have far-reaching implications for the accepted view of the evolutionary human family tree.

Fossils from Georgia

The fossils come from Dmanisi, a site in southern Georgia that has provided an extensive amount of early human fossil material, documenting the earliest migrations of hominins into Eurasia.  The scientists led by David Lordkipanidze, a palaeoanthropologist at the Georgian National Museum (Tbilisi), have spent eight years studying the various fossil bones, many of them fragmentary but their research has amassed enough evidence to suggest a re-writing of the Homo genus.

The paucity of the global fossil record for humans has left scientists with a large number of gaps in the human family tree.  These species currently recognised as distinct members of the Homo genus, the likes of Homo erectus, Homo ergaster and Homo habilis may represent variation amongst members of a single, evolving lineage of humans.

Put into simple terms, people look different from each other today, although they are all members of a single species (H. sapiens), so did early hominins look different from one another?  The wide variation seen in the fossil bones could perhaps have led scientists to establish a number of species, when perhaps, the fossils represent a single human form.

Scientists Attempt to Unravel Human Evolution

Skulls and jaws from the site in Georgia.

Picture credit: Science

The picture above shows some of the distinct differences between hominin fossils excavated from the Dmanisi location.  The skull on the left for example, has a much broader face than the skull on the right, the cheekbones are more pronounced, the brow ridges are more defined and prominent when compared to the specimen on the far right.  One of the jawbones (to the left of the picture), is significantly deeper than the specimen adjacent to it.

Considerable Variation Amongst the Specimens

This is the conclusion drawn by the research team led by David Lordkipanidze and reported in the academic publication, “Science”.  A hominin cranium excavated in 2005, a fossil referred to as “skull 5” or more specifically (D4500) and described as being “the world’s first completely preserved adult hominid skull”, when combined with a fossilised mandible (jawbone) found at the same location (D2600), provided the key evidence that led to the simplified human evolution theory.  This skull was dissimilar to other human remains found at the dig site, it had a number of primitive features such as a long ape-like face, large teeth, a much smaller braincase and a more substantial lower jaw.

Together D4500 and D2600 represent the best example yet found of an adult hominin skull from the early Pleistocene epoch.

The Dmanisi Site

The fossil haul from the Dmanisi site, which now comprises five crania, provides direct evidence of wide morphological variance amongst early Pleistocene hominids.  The Dmanisi fossils have permitted the research team to study the physical traits of Homo genus members that apparently lived at the same location and at approximately the same time.   The small braincase, as indicated by D4500 at approximately 546 cubic centimetres is only about 10% bigger than the average braincase size found in extant Western Lowland Gorillas (Gorilla gorilla).

These primitive characteristics found amongst other hominin remains that show more “human-like” anatomical traits suggests that rather than types of human species, there could have been just a single, evolving lineage of early humans.

The scientists have concluded that the differences between these fossils were no more pronounced than the differences between any given five members of our own species H. sapiens or from five chimpanzees.

The Basis for a new Homo Species?

Such morphological differences had been used as the basis to establish new species in the human evolutionary family tree.  For example, the hominin fossils from Dmanisi, evidence of the earliest Europeans, had been assigned to the new species of H. georgicus.  If this new hypothesis becomes the accepted norm, then fossils assigned to the likes of H. ergaster may have to be re-examined.

Commenting on the results of the study, co-author Christoph Zolikofer (University of Zurich) stated:

“Had the braincase and the face of Skull five been found as separate fossils at different sites in Africa, they might have been attributed to different species.  Since we see a similar pattern and range of variation in the African fossil record, it is sensible to assume that there was a single Homo species at that time in Africa. As the Dmanisi hominids are so similar to the African ones, we further assume that they both represent the same species.”

The very first hominins evolved in Africa, it is only in strata less than two million years old that palaeoanthropologists start to find evidence of a migration of early humans out of Africa into Europe and Asia.  This first phase of human migration out of their ancestral home coincides with a period of dramatic climate change.  There was an extensive period of global cooling.  Many of the apex, mammalian predators that had existed in North Africa became extinct and it has been proposed that the lack of competition for meat that hominids now faced help to drive the migrations into Europe and beyond.

The further north (or south) one travels, the greater the contrast between seasons.  If the world cooled and mankind’s homelands of Africa grew colder, than this in conjunction with the absence of other animal competitors could have helped fuel the movements north.  After all, if Africa was colder than early hominins would have had to adapt to the new climate, predisposing them to being able to cope better with colder climates at more northerly latitudes.

A spokesperson from Everything Dinosaur commented:

“This recently published paper provides a new perspective on the evolution of our own species.  The fossil record of early hominins and evidence for their potential migration out of Africa is very poor and much more research is needed in this area.  Perhaps, in future, scientists will not use species definition to distinguish different forms of ancient human but rely on analysis of stone tool use to establish a range of different progressions in technology to chart the evolution of the human population as we know it today.

Post cranium elements found amongst the medieval ruins of a castle that marks the Dmanisi dig site suggest that the Dmanisi hominins were shorter than modern humans, but they were fully upright bipeds with leg bones capable of efficient locomotion.  These traits help distinguish these fossils from much earlier material still attributed to the Australopithecus genus.  Australopithecines are believed the ancestors of the Homo genus.

Diplodocus Fossil to be Auctioned in the UK

The fossilised remains of a Diplodocus longus are due to be sold at an auction in the United Kingdom next month.  The specimen, nicknamed “Misty” measures approximately seventeen metres long and dates from the Late Jurassic of Wyoming.  The fossils are estimated to be around 150 million years old and as articulated sauropod skeletons are extremely rare in the fossil record, the lot is likely to sell for around £600,000 GBP ($960,000 USD).

Diplodocus Dinosaur Fossil

The Diplodocus is one of a number of rare fossils and other artefacts being sold by Summers Place Auctions, based in West Sussex (England), on November 27th as part of an auction entitled “Evolution”.  Other lots include Dodo remains, a specimen of the Jurassic marine reptile Ichthyosaurus communis from Dorset, which itself is estimated to fetch up to £80,000 GBP ($128,000 USD) and a rare, stuffed Tarpan.  The Tarpan is an extinct sub-species of the Eurasian Wild Horse.

The fossils, especially the Diplodocus exhibit will attract a great deal of interest no doubt.  However, we at Everything Dinosaur remain concerned when such specimens are offered up for sale in this way.  The specimen was excavated from the privately owned Dana Quarry in Wyoming, whilst there are restrictions placed on the movement and sale of fossils found on Bureau of Land Management land within the United States, as the Diplodocus fossils come from private property, these restrictions do not apply.

Illegal Excavations and Fossil Smuggling Concerns

The concern is that specimens such as this would end up in the hands of a wealthy individual or corporation, who subsequently, may not permit the specimen to be used in further research.  Therefore, a potentially scientifically valuable fossil is lost to the scientific community.  Sales of this kind, may also indirectly encourage illegal excavations and the smuggling of fossils.  High profile sales of dinosaur fossils, ones that fetch hundreds of thousands of pounds, could motivate individuals to break existing laws in a bid to exploit the situation and to profit from the high prices paid for such specimens.

The counter argument to this is that a large number of important specimens would never been found at all, if it were not for the activities of professional fossil dealers.  Many significant fossils could erode away if it were not for the commercial companies and individuals that constantly explore fossil bearing strata in a bid to discover potentially valuable specimens.

A Female Diplodocus?

The Diplodocus, believed to represent a female, was found in 2009 by Benjamin and Jacob, the sons of palaeontologist Raimund Albersdoerfer, who were exploring the Dana Quarry site.  It took the dinosaur hunters a total of nine weeks to excavate all the fossil material representing the Diplodocus from the dig site.  The fossil material was then sent to a specialist laboratory in Holland for further preparation before being offered for sale.

A Model of a Rearing Diplodocus Dinosaur

The CollectA rearing Diplodocus dinosaur model in the elephantine colour scheme. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The picture (above) shows a CollectA Age of Dinosaurs Popular Diplodocus figure.

To view this range available at Everything Dinosaur: CollectA Age of Dinosaurs Popular Models and Figures.

Errol Fuller, one of the people responsible for managing the exhibits to go into the auction commented:

“It’s perfectly legal to bring it from America and legal to move it to any country in the world.  Museum workers will sometimes try to stop these things… but almost every great fossil discovery was made by fossil collectors or dealers.”

The Auction of Fossil Specimens

The auction of specimens such as this have proved controversial.  In May of last year, Everything Dinosaur reported on the seizure of a Tarbosaurus fossilised skeleton that had been auctioned in New York.  Allegations that the fossil had been illegally removed from Mongolia were later proven.  The fossil was recently repatriated to its country of origin.

To read more about the Tarbosaurus skeleton being seized: Tarbosaurus Fossil Seized by U.S. Authorities.

Another high profile auction of fossils is due to take place just a few days before the Diplodocus goes under the hammer.  Bonhams (New York), on the 19th November will be overseeing the auction of a chasmosaurine dinosaur and a suspected Nanotyrannus, a lot which has been entitled the “duelling dinosaurs”.  In this case, the fossils originate from Montana.

To read more about the “duelling dinosaurs” auction: “Duelling Dinosaurs” likely to set World Record at Auction.

Let’s hope that whatever, the outcome, the fossils and other artefacts that are part of this auction are made available for further study should the need arise.

A First for Biology – Blood Meal of an Insect Found Intact in a Fossil

In the steamy swamplands of what was to become the north-western part of the United States forty-six million years ago a tiny, insignificant event took place.  An event which had been replicated in that area hundreds, perhaps thousands of times that day.  A tiny mosquito used its needle-like proboscis to penetrate the skin of a vertebrate and took a meal of blood from its victim.  Nothing remarkable about that you might say, but what happened next gave the opportunity for scientists to comment on this incident forty-six million years later.

Ancient Mosquito Fossil

The tiny midge, for some reason stalled in its flight over a body of water.  Perhaps a sudden gust of wind forced the insect to crash land onto the surface of a pond.  The mosquito quickly sank to the bottom, remarkably its body remained intact and it was quickly buried, preserving it and its distended abdomen filled with blood.  The insect was fossilised and researchers exploring these Palaeogene deposits that now make up part of a mountainside in the state of Montana (USA), were able to view the tiny fossilised insect and postulate that the distended body contained the remains of its last meal.

A Window into the Past, The Preserved Mosquito Fossil

Mosquito fossil with potentially preserved blood in its abdomen.

Picture credit: Smithsonian Institute/Dr Dale Greenwalt

Blood Preserved in Insects Trapped in Amber

It might sound like something that the author Michael Crichton would have written about.  Mr Crichton wrote “Jurassic Park”,  a story of the failed attempt to open a dinosaur theme park with the Dinosauria being resurrected by genetic manipulation of blood preserved in the bodies of insects trapped in amber.  Fanciful stuff perhaps, but a paper in the academic journal “The Proceedings of the National Academy of Science” outlines the study of this beautifully preserved fossilised insect, potentially evidence of the oldest blood yet found in the fossil record.

For models and replicas of prehistoric invertebrates and other extinct creatures including dinosaurs: CollectA Age of Dinosaurs Popular Models.

Retired Dr Dale Greenwalt collects and studies insect fossils from the Montana deposits on behalf of the Smithsonian institute.  The fossils, were discovered in fine grained shales that had been collected many years before and placed in storage.  The female mosquito (only females feed on blood), had been trapped and nearby the remains of a second mosquito, this time most probably a male, was discovered.  Using two different types of light-refracting x-rays that determine what chemicals are present along with advanced, non-destructive mass spectrometry analysis Dr Greenwalt and his colleagues determined that the female mosquito’s abdomen was full of iron, a major feature of blood that gets oxygen to the rest of the body.

Iron levels were higher than elsewhere in her body and no significant levels of iron were identified in the non-biting male mosquito fossil that was used as a control.  The scientists also found evidence of porphyrins, organic compounds that play an important role in blood formation and helping to bind the iron within the blood.  These two substances found together makes a “definitive case for blood” according to the researchers.

A “Definitive Case for Blood”

If this is proven to be true, the tests being verified, then this little mosquito preserves the oldest sample of blood known to science.

But where did the blood come from?  Could it be a dinosaur?  Sadly, most definitely not, the last of the Dinosauria became extinct some twenty million years before the mosquito hatched.  The blood will have come from a vertebrate, most likely a bird according to Dr Greenwalt.

Dr Mary Schweitzer (North Carolina State University), a leader in the research to find microscopic soft tissues preserved in fossils, including the possibility of blood remnants associated with dinosaur fossils from the Hell Creek Formation of Montana, commented that whilst the study was exciting and significant, the research was in its preliminary phase and more work needs to be done to prove the conclusion by ruling out all other possibilities for the unexpected results showing iron concentrations and the possibility of other preserved organic compounds such as the suspected porphyrins.

Dr Greenwalt stated:

“The existence of this rare specimen extends the existence of blood-feeding behaviour in this family of insects 46 million years into the past.”

Blood feeding, otherwise known as haematophagy, occurs in approximately 14,000 living insect species including fleas, ticks and modern mosquitoes.  These fossils are so well preserved that the scientists have been able to name them as two new species of insect.  The female has been named Culiseta lemniscata, the male mosquito has been named as Culiseta kishenehn.  Next time you get bitten by a midge, think on, that incident might, just might, lead to your blood being preserved for forty-six million years or so.