Salt Lake in northwestern Iran Mirrors Permian Environmental Crisis

Observations made as environments change today can sometimes provide scientists with valuable insights when it comes to studying the fossils of extinct creatures.  Studies into the way climate change affects animals and plants can provide researchers with helpful information when it comes to interpreting fossil evidence.  One such example of this concerns comparisons being made by scientists as Lake Urmia in northwestern Iran dries up to the plight of an ancient ecosystem that was to form part of South America.

Lake Urmia

For Iranian biologist Amin Khaleghparast and Dr Graciela Piñeiro (from Uruguay), breeding stress observed amongst Lake Urmia’s Flamingo population might be mirroring stress amongst a population of ancient Parareptiles as their environment changed.  Lake Urmia was the third largest salt water lake on Earth, and the largest body of salty water in the entire Middle East.  However, over the last fifty years or so the volume of the Lake has been much reduced.  Dams constructed across the rivers that feed Lake Urmia, the increasing demand for water for agriculture and the impact of severe droughts have reduced the Lake to a fraction of its former size.

The Flamingos are filter feeders and rely on brine shrimp (Artemia urmiana) as a food source.  As the water volume of the Lake is reduced, much of what was formerly open water is changing into a salt marsh.  This has led to a reduction in suitable habitat for the Flamingos and a decline in brine shrimp numbers.  With the drying up of Lake Urmia the scientists have witnessed a severe decrease in Artemia populations which has had dire consequences for other animals further up the food chain, including the Lake’s Flamingos.  Many Flamingos have failed to breed, a number of eggs have been aborted and a substantial number of Flamingo hatchlings have died.

Drawing Parallels with the Permian

The scientists have drawn parallels between these observations and a similar situation that may have affected a population of reptiles, (mesosaurs) in South America some 280 million years ago.

To read a short article on the drying up of Lake Urmia: The Ecological Crisis at Lake Urmia.

Dr Piñeiro and her colleagues produced an academic paper, published in 2012 (International Journal of Paleobiology), that highlighted the discovery of a number of Mesosaurus fossils including amniotic embryos, some of the earliest evidence yet of reptile embryos and possible viviparity (live birth) in the Reptilia Class.  Intriguingly, the discovery of an isolated embryo might suggest breeding stress in the population that led to the abandonment of this egg or a possible miscarriage.

Mesosaurs

Mesosaurs such as Mesosaurus were small aquatic reptiles that lived during the Permian.  They had elongated jaws lined with very fine, needle-like teeth that would have helped them to strain arthropods such as brine shrimps out of the water in which they lived.  These reptiles were perhaps the first group of amniotes to adapt to living in marine habitats.  Although mesosaurs are descended from terrestrial reptiles, their long, flexible bodies, paddle-like tails and webbed digits indicate adaptations to a nektonic, marine lifestyle.  These reptiles had thickened ribs which palaeontologists believe was an adaptation to help these small animals counteract their own buoyancy and helped them to remain underwater.

Mesosaurus Specimens

Ancient reptiles adapted to marine environments.

Picture credit: Everything Dinosaur

The scale bar in the picture is approximately seventy-five centimetres long.

Permian Reptilian Fauna

Although, these animals were not the most spectacular looking of the Permian reptilian fauna, their fossils, which have been found in Uruguay, Brazil as well as in western Africa helped to reaffirm the theory of continental drift first proposed by the German meteorologist Alfred Wegener.   Wegener observed that the coastline of west Africa fitted neatly into that of South America’s east coast, even though the Atlantic Ocean separated these two landmasses.  He proposed that some time in the past these two continents had been joined together.  His observations were supported by fossil evidence of creatures such as the mesosaurs which have been found in rocks on now widely separated continents.  Mesosaurs were unlikely to be capable of crossing such vast bodies of water as today’s oceans, so such fossils supported the idea that some time back in ancient history South America and Africa were joined together.  Such evidence helped to establish the theory of plate tectonics (continental drift).

The Fossil Record Provides Supporting Evidence for Plate Tectonics

Fossils support evidence of plate movements.

Plate Tectonics

The diagram above shows where fossils of Mesosaurus, lystrosaurs (a terrestrial dicynodont), Cynognathus (a terrestrial cynodont) and Glossopteris (a pteridosperm [seed fern]) have been found.  These discoveries provide supporting evidence for the theory of these disparate land masses once being joined into a super-continent.

In the Carboniferous, a group of terrestrial animals evolved that would eventually dominate vertebrate life on our planet. These were the amniotes a group that includes mammals, birds and reptiles today.  The early amniotes evolved a unique way of protecting embryos inside their eggs.  Amniotic eggs have a semi-permeable shell that protects the egg from drying out.  An internal membrane known as the amnion surrounds the yolk and the embryo, this effectively means that the free-swimming larval stage seen in the Amphibia could be dispensed with.  Later synapsid amniotes evolved the ability to retain embryos internally thus affording the embryo greater protection (as seen in extremis in marsupial and placental mammals today).

Amin Khaleghparast and Dr Graciela Piñeiro postulate a relationship between an ancient salt lake in Pangea and Lake Urmia:

“There is it some similarity between intense evaporation of the ancient Great Salt Lake where Mesosaurus lived and conditions that lead to the drying Lake Urmia, a great salt lake in northwestern Iran, turning large part of it into a salt marsh in last decade. Like Flamingos filter-feed on brine shrimp (Artemia urmiana) in the salt lake, Mesosaurus filter-fed on an extinct group of crustaceans (Pygocephalomorpha) in waters poorly oxygenated and highly saline during the Early Permian. With the drying Lake Urmia,unfortunately, we witnessed severe decrease of Artemia, Flamingos’ abortion, death of many Flamingo young and at last Flamingo migration.”

Mesosaur Fossil Discovery

The discovery of an isolated fossilised embryo could demonstrate that the population of mesosaurs was under environmental pressure as their habitat changes.  According to the scientists this fossil could represent “either a miscarried embryo or an aborted egg”.

The bodies of the animals perished in hypersaline conditions, the degree of preservation is exceptional.  This can be explained by the fact that hypersaline states are associated with very low concentrations of oxygen which in turn creates an environment in which bacteria, responsible for the decomposition of organic matter cannot act.  These amniotic mesosaur embryos provide some of the earliest evidence yet of reproduction biology of vertebrates preserved in the fossil record.  In some specimens, the absence of a recognisable eggshell in association with articulated well-preserved embryos within an adult suggest that mesosaurs may have been viviparous or at least that they laid eggs in an advanced state of development.

Mesosaurus Embryo Fossils – Did they Face the Same Fate as Lake Urmia’s Flamingos?

Sharing the same fate as Lake Urmia’s Flamingos?

The picture above shows on the left the fossil of the meosaurus embryo curled up within its amniotic membrane (no egg shell preserved).  The middle component shows a stylised tracing of the fossil, with a life-size drawing of the Mesosaurus embryo on the right.

To read more about the South American fossil discoveries: Early Evidence of Viviparity from South America.

Everything Dinosaur acknowledges the help of Amin Khaleghparast in the compilation of this article and for pointing out the relationship between Lake Urmia and the drying up of shallow seas in the Carboniferous.

A tourist to the south eastern tip of what was to become the continent of Africa 350 million years ago would have had to watch where they were treading as scorpions were lurking amongst the primitive plants.  We know this because Dr Robert Gess from the Evolutionary Studies Institute at the University of Witswatersrand (Johannesburg), has discovered the fossilised exoskeleton of one such creature.  This unique specimen, a new species named Gondwanascorpio emzantsiensis represents the oldest known terrestrial animal from the super-continent of Gondwana discovered to date.

Gondwanascorpio emzantsiensis

Fossils of terrestrial animals are known from the super-continent of Laurasia, but this is a first for the ancient landmass that dominated the Southern Hemisphere during the Late Devonian and into the Carboniferous.

A Photograph showing the Scorpion’s Pincers (Gondwanascorpio emzantsiensis)

Picture credit: University of Witwatersrand

Oldest Known Terrestrial Animal

Commenting on his fossil find, Dr Gess stated that early life arose in the sea and that colonisation of the land took place much later on in the history of life on Earth.  This process is believed to have begun back in the Silurian geological period, approximately 420 million years ago, although some palaeobotanists have suggested that microscopic spores preserved in Ordovician strata indicate that plant life was established on land even earlier.

Once plants had become established on land in significant numbers, then detritus and plant eating invertebrates followed, animals such as primitive arthropods.  By the Late Silurian, around 415 million years ago, terrestrial food chains were much more complex with apex predators such as mites, scorpions and early spiders feeding on the herbivorous invertebrates.  By the Late Devonian, some 365 million years ago, the first vertebrates (tetrapods) had ventured out onto land.

The First Tetrapods

Some palaeontologists believe that the first vertebrates were established on land some 390 million years ago, click the link below to read an article published by Everything Dinosaur in 2010, that provides details of a remarkable fossilised trackway studied by Polish scientists: Tetrapods Venture onto Land Thirty-Five Million Years Earlier.

Fossils found in Palaeozoic strata that represent the land mass of Laurasia, a super-continent the straddled much of the northern hemisphere in the Devonian, suggest that this landmass was inhabited by a diverse and abundant group of invertebrates.  Laurasia and Gondwana were separated by an ocean over a thousand miles across at its widest extent.

Evidence of the earliest colonisation of land animals has until now come only from the Northern Hemisphere continent of Laurasia (land that was to form North America, parts of Europe and Asia), and there has been no evidence that Gondwana was inhabited by land living invertebrate animals at that time, however, the discovery of this Southern Hemisphere scorpion suggests that Gondwana too, had its fair share of creepy crawlies.

An Invertebrate Predator on Land

The discovery of an invertebrate predator leads to the assumption that there were other invertebrates present that this creature would have fed upon.  This new species has been named Gondwanascorpio emzantsiensis.

Dr Gess stated:

“For the first time we know for certain that not just scorpions, but whatever they were preying on were already present in the Devonian.  We now know that by the end the Devonian period Gondwana also, like Laurasia, had a complex terrestrial ecosystem, comprising invertebrates and plants which had all the elements to sustain terrestrial vertebrate life that emerged around this time or slightly later.”

The Witpoort Formation

The fossil fragments were found in black carbonaceous shale which represents a marine lagoon and an estuarine environment.  The fossiliferous material is from the Witpoort Formation (Witteberg Group) at a location known as Waterloo Farm, near Grahamstown, South Africa.  Other organic material identified includes traces of algae, terrestrial plants, small fish, a sea scorpion (Eurypterid) and a number of molluscs.  All the fossil material ascribed to G. emzantsiensis consists of two-dimensional compressions in which all the original organic material has been replaced by secondary metamorphic mica.  The mica has largely been altered to chlorite during the uplifting of the strata.  The Witpoort Formation strata at the Waterloo Farm location were laid down towards the end of the Devonian (Famennian faunal stage), approximately 360 million years ago.

A Close up of the Preserved Pincers

Picture credit: University of Witwatersrand

The Discovery of a Palaeozoic Scorpion

The fossil material represents the first discovery of a Palaeozoic scorpion from Gondwana.  In the scientific paper, published in the academic journal “African Invertebrate”, the researchers note that this fossil find is extremely unusual as it comes from rocks deposited at a far higher latitude (much closer to the South Pole), than that at which extant or fossil scorpions are known to have occurred.  The authors suggest that this discovery may suggest that the climate in the southern hemisphere during the Late Devonian was much more uniform than it is today.  Temperatures at high latitudes may have been much higher than they are today.

Gondwanascorpio emzantsiensis Possessed a Powerful Sting

Picture credit: University of Witwatersrand

Devonian Ecosystems

The scientists report that the presence of this scorpion from Gondwana, one that is similar to already described Laurasian taxa is consistent with the growing body of evidence that suggests globally comparable terrestrial ecosystems by the end of the Devonian.  Gondwanascorpio, as the oldest terrestrial animal from Gondwana and its fossil material along with progymnosperm plant material (Archaeopteris) that has also been described from fossils found at Waterloo Farm, suggests that marine marginal ecosystems may have been very similar across the world during the Late Devonian.  It has been speculated that this uniformity may have been a consequence of the increasing proximity of Laurasia to Gondwana as the deep ocean that once separated these super-continents began to close up.

The Location of the Waterloo Farm Site Mapped onto a Late Devonian Map of Gondwana

Picture credit: University of Witwatersrand

The map above shows a reconstruction of the super-continent of Gondwana with the South Pole represented by a large black star.  The Waterloo Farm location is marked by the symbol “WF”.  The map shows the position of landmasses towards the end of the Devonian/early Carboniferous.  The Waterloo Farm deposits are coastal and close to the South Pole.

Everything Dinosaur acknowledges the assistance of a media release from the University of Witwatersrand in the compilation of this article.

For models and replicas of Palaeozoic creatures: CollectA Prehistoric Life Replicas.

Neanderthals Shaped Animal Bones So That They Could Work Leather

For many thousands of years, modern humans (Homo sapiens) and Neanderthals (Homo neanderthalensis) lived in western Europe, it is not known how much interaction there was between these two species of hominids.  Neanderthals, far from being the slow-witted, ape-men of Victorian literature were very well adapted to living in cold climates, skilled tool makers and very capable hunters. In Neanderthal fossil sites dated to near the time when this species became extinct, a few thousand years after the arrival of modern humans in western Europe, tools and other objects have been found that are very similar to those found in contemporaneous fossil sites of modern humans.

Neanderthals

Neanderthals show behaviours similar to those associated with modern humans and have similar fine tools, such as small stone blades and bone implements.

Evidence of Neanderthals Being Skilled Leather Workers

Human and Neanderthal genetic research. Evidence suggests that Neanderthals were skilled leather workers and therefore able to make clothes.

The picture (above) shows two CollectA Neanderthal models, to view these replicas (whilst stocks last): CollectA Prehistoric Life Figures.

Sophisticated Behaviours

It had been thought that much of these sophisticated behaviours inferred from artefacts found at Neanderthal fossil sites, had been developed as a result of contact between Neanderthals and our own species.  Modern humans arrived in western Europe around 40,000 years ago and it is after this date that such sophisticated tools turn up in Neanderthal dig sites.

In a new study, published in the academic journal the Proceedings of the National Academy of Sciences (USA), a team of researchers report the discovery of specialised bone tools previously only associated with Homo sapiens that date from a Neanderthal site that is at least 50,000 years old  – before (so it is thought),  the arrival of modern man in western Europe.  This suggests that Neanderthals did not learn sophisticated tool making skills from us, they may have developed such technologies themselves.

Tools Made from Animal Bones

Co-author of the study, Zenobia Jacobs of the University of Wollongong (New South Wales, Australia) stated that the tools were polishing tools made from animal bones.  These “lissoir” tools were used to work the hides of animals and the Neanderthal bone tools predate similar discoveries made in western Europe by about 10,000 years.

The tools were found in south-western France and the University of Wollongong has been engaged in a major project to assess Neanderthal and early human European cultures.  This new study, forms just part of the University’s research.

This discovery implies that the two hominid species either learned how to work animal skins separately, or modern humans may have picked up the skills required from the Neanderthals.  Dr. Jacobs suggests that it may have been the later, with modern humans learning from Neanderthals.

The Bone Tools Discovered at the Site in South-western France

Bone tools shaped by Neanderthals for working animal skins.

Picture credit: Proceedings of the National Academy of Sciences

Picture A shows a bone tool, the dotted line shows the original shape of the bone before it was sculpted and shaped into a tool for use in leather work.  The close up images of the bones show evidence of wear as seen in modern lissoir tools used today in the fashion industry.

Used to Prepare Animal Hides

Dr Jacobs said the tools were used to smooth and burnish deer hides and make them water resistant.  They were identically shaped to plastic lissoir tools used today by top fashion houses.  The specialised bone tools  have microscopic wear patterns preserved on them, the wear is consistent with the use of lissoir in modern times to obtain supple, lustrous, and more impermeable hides.

The discovery contradicts theories that Neanderthals were “cognitively challenged dead-ends” who had been supplanted by Homo sapiens because they were stupid, Dr Jacobs said.  Neanderthals have also been found to have had the genetic and anatomical features necessary for speech.

Dr Jacobs added:

“I don’t think they were stupid at all.  They were probably quite capable of inventing all sorts of things that modern humans would like to claim as their own.”

Smart Neanderthals

Dr Jacobs commented that  it had long been believed that humans began behaving in a modern fashion, characterised by the use of symbols, when they reached Europe.

“Now it’s generally accepted that we probably had those abilities over the last 100 to 150 thousand years,” the doctor stated.

While it is not clear why Homo sapiens displaced the Neanderthals, Dr Jacobs said there had been plenty of interbreeding and most people now had between 2.5 per cent and 4 per cent of Neanderthal DNA in their genes.

She quipped:

“Maybe those leather workers are the ones with more Neanderthal genes.”

As these finds clearly predate the oldest known age for the use of similar objects in Europe by anatomically modern humans, they could also be evidence for cultural diffusion from Neanderthals to modern humans.