20,000 Fossils Provide Glimpse into Marine Ecosystem Post Mass Extinction Event

A hillside in south-west China has revealed a treasure trove of beautifully preserved fossils, capturing an almost entire ecosystem and providing scientists with an insight into how life on Earth recovered from the Permian mass extinction event.  The discovery of such a wealth of fossil material may help scientists to understand more about how ecosystems and natural communities recover from extinction events.

The mass extinction event that ended the reign of the dinosaurs may be better known, but the extinction event some 250 million years ago that ended the Permian Period was more severe with an estimated 95% of marine animal species dying out.  Scientists have calculated that approximately two-thirds of all the land vertebrate families also died out.  One of the factors involved in the mass extinction was a huge reduction in the total area of shallow continental shelf sea environments as plate movements created one, global, large land mass.  Ironically, the 16-metre-thick limestone sediments that have yielded the fossils represent the deposits at the bottom of a shallow, marine environment.

Permian Ecosystem

The record of this ancient marine ecosystem forms part of a hillside in Luoping County, Yunnan Province, south-west China.  Since 2007 teams of fieldworkers and researchers have been carefully examining and extracting fossils, mainly invertebrates such as molluscs, sea urchins and arthropods but also fish and marine reptiles including ichthyosaurs.  Something like 20,000 specimens have been discovered so far, many of which have had soft body parts preserved providing palaeontologists with a huge amount of data about life in the Early Triassic, post the Permian mass extinction event.

The excavation work was supervised by scientists from the Chengdu Geological Centre in China and the paper, which was co-authored by Professor Michael Benton (Bristol University) has been published in the scientific journal “The Proceedings of the Royal Society B (Biology)”.  The site preserves evidence of an entire marine ecosystem, providing scientists with an understanding of how organisms recovered from the Permian mass extinction event.

Amongst the many beautifully preserved remains are those of some of the earliest large marine reptiles known from the Triassic.  These animals would have been the apex predators, at the top of the food chain.  The biggest creature discovered so far is a thalattosaur (name means “ocean lizards”), a type of marine reptile over 3 metres long, which would have preyed upon the larger fishes that lived in the shallows.  The exact phylogeny of the thalattosaur group is not known, but most scientists believe that this group should be placed between the later ichthyosaurs and more primitive archosaurs that adopted a marine habit.

A Model of an Ichthyosaur

The Ichthyosaurus model (Wild Safari Prehistoric World) ready to take its turn on the Everything Dinosaur turntable. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

To view the Wild Safari Prehistoric World range: Wild Safari Prehistoric World Figures.

The Chinese scientists also unearthed a number of ichthyosaurs, providing evidence of the evolutionary origins of this important group of marine predators.

Professor Shixue Hu of the Chengdu Geological Centre stated:

“It has taken us three years to excavate the site, and we moved tonnes of rock.  Now, with thousands of amazing fossils, we have plenty of work for the next ten years.”

Commenting on the discovery, Professor Benton (Bristol University) added:

“The fossils at Luoping have told us a lot about the recovery and development of marine ecosystems after the end-Permian mass extinction.  There is still more to be discovered there and we hope to get an even better picture of how life reasserted itself after the most catastrophic global event in the history of our planet.”

He went onto comment:

“The few hardy species that survived the ensuring scarcity of food, wild fluctuations in temperature and shortage of oxygen in the ocean served as the starting point for the recovery of life in the next geologic period, known as the Triassic.”

Until the discovery of the extensive fossil site at Luoping, very little fossil material from the Permian/Triassic boundary was known.  The strata has been dated to approximately 245 million years ago, providing an insight into the rise of life forms after a mass extinction event.

Only about half the site has been explored to date, scientists are confident that many new species will be unearthed.  The site has provided the researchers with a better understanding of how groups of organisms recovered from the extinction event.  It seems that small, marine invertebrates recovered first, with ammonoids (cephalopods – ammonites) reaching precataclysm levels of diversity within two million years, as did snails and other molluscs such as clams and oysters.

However, it seems that the severity of the extinction event meant that it took around ten million years for a fully established ecosystem to develop.  The site has also a number of fossils of land based organisms, including reptile teeth and plant material such as fir cones.  These items were washed into the sea by rivers that emptied into the shallow bay.

A fossil tooth is so well preserved that the serrated edges of the tooth can still be made out.  Archosaurs became the dominant land reptiles during the Triassic, the tooth was washed into the sea after having been shed on land.

For models and replicas of prehistoric animals: Prehistoric Animal Models and Replicas.

More Superb Ichthyosaur Material from Lyme Regis

A few months ago, whilst perusing a tides timetable that a colleague had picked up whilst visiting Dorset, we realised that there were going to be some exceptionally low tides in the Lyme Regis area.  This, in combination with the stormy weather that the Dorset coast had endured recently, made us confident that lots of fascinating fossil material would soon be discovered on the beaches surrounding Lyme Regis and Charmouth.

To read our article predicting fossil finds: Low Tides could lead to a Fossil Finding Bonanza.

Sure enough, keen eyed amateur palaeontologists, holiday makers and fossil hunters were soon finding lots of new fossils, all exposed due to the low tides and additional erosion caused by the bad weather.  We have heard about a number of marine reptile remains that were discovered in the days and weeks following our original article.

Pictures show a very well preserved section of the backbone of an ichthyosaur (caudal vertebrae), Brandon Lennon, the expert fossil hunter who discovered this particular piece estimates that it is part from a specimen that would have measured more than 4 metres long in total.

For models and replicas of ichthyosaurs and other marine reptiles: CollectA Age of Dinosaurs Popular Range.

Lyme Regis Fossil Dealer Mike Jeffries with Ichthyosaur Vertebrae

Picture credit: Mike Jeffries/Brandon Lennon.

Note how the rock matrix is being held (the rock surrounding the actual fossil material), fossilised bones should not be touched unless absolutely necessary.  The hand provides scale and the photograph shows the fossil the correct way up (neural spines seen at the top of the vertebrae).

The picture above shows, Lyme Regis fossil dealer, Mike Jeffries with another section of ichthyosaur vertebrae (lateral view).  This carefully prepared articulated fossil reveals plenty of detail – the round, dished vertebrae with blocky neural spines protruding above them.  The fossils were prepared and cleaned by Dorset based expert fossil developer David Costain.

Lyme Regis Fossils

Brandon Lennon had found two sections of the backbone about a year ago, the other (middle section of the final prepared fossil), was missing, but Brandon found the “linchpin” vertebra recently so the whole piece could be reconstructed.  With the discovery of the missing vertebra a section of ichthyosaur could be connected together again.

To see more Lyme Regis fossils: Brandon Lennon’s Fossil Site.

Visit the Everything Dinosaur website: Everything Dinosaur.

Canadian Scientists Discover new source of Cambrian Fossils

A team of Canadian scientists have discovered a treasure trove of Cambrian fossils, including eight new taxa at a location high in the Canadian Rockies, just 25 miles from the famous Burgess Shale sites.  This discovery may herald a new era in palaeontology as more Cambrian fossil sites may exist, many more than previously thought.

Cambrian Fossils

It was the famous American palaeontologist Charles Walcott, who first came across a profusion of fossils in shale beds, at the site that was to become known as the Burgess Shale.  He found the fossils quite by accident as he walked along a high ridge in the Rockies.  The date of his discovery was 31st August 1909, now a team of Canadian researchers exactly, one hundred and one years and one day later, have announced the discovery of a new fossil rich location that could put the Burgess Shale in the shade.

Burgess Shale fossils are so important, as not only are the hard parts of organisms preserved, but in many cases evidence of soft tissues and actual body parts have also been preserved.  Many palaeontologists regard the specimens from the Burgess Shale as the most perfectly preserved fossils from any geological period, quite an accolade as the strata dates from more than 500 million years ago.

It had been thought that the Burgess Shale fossils were unique and that no other locations would have the exact geological features that would have permitted such a large amount of fossil material to be preserved.  With the discovery of this new fossil rich site, with its own exquisitely preserved specimens, just 25 miles from the original Burgess Shale location, many more such fossil rich areas may soon be discovered.

Burgess Shale Deposits

The creatures entombed in the Burgess Shale deposits inhabited a marine environment directly under a submarine cliff.  Mudslides from this cliff buried these animals, but significantly the mud was low in oxygen.  Rapid burial in a de-oxygenated environment led to a slowing down in the decomposition of body tissues.  Often these tissues were permineralised (replaced by minerals) and consequently much better preserved.

Burgess Shale fossils actually occur in several locations, but they are all contained within a small area of the Rockies, around the little town of Field in Yoho National Park (British Columbia).  All the fossils are found in strata belonging to the Stephen Formation, which in some parts is extensively exposed and represents deposits over 250 metres thick.

However, a team of scientists led by palaeontologist Jean-Bernard Caron of the Royal Ontario Museum (Toronto) have reported finding Burgess-like fossils in the valley of the Stanley Glacier in Kootenay National Park.  At this location, the Stephen Formation is exposed but in much thinner strips, no more than 160 metres thick.

Writing in the scientific journal “Geology” the team report that about 50% of the animal groups represented at the Stanley Glacier site have been found at other Burgess Shale locations, but in different abundances.  This information will help the scientists to learn more about the evolution and diversity of arthropods such as the Trilobites for example.

A New Fossil Site

Trilobites were a highly successful Order of marine arthropods, that arose in the Cambrian and eventually became extinct at the end of the Permian approximately 250 million years ago.

A Model of a Trilobite

Picture credit: Everything Dinosaur

To view more amazing prehistoric animal models including a trilobite model: CollectA Prehistoric Life Models.

Commenting on this new site, Peter Allison, a geoscientist at Imperial College (London) stated:

“This new locality adds to our knowledge of the environments where these organisms lived and died and thus adds important context.”

Eight new taxa, previously unknown to science have also been unearthed.  These new organisms include a new, as yet unnamed worm, a new member of the anomalocarids, a predatory group of nektonic (actively swimming) predators and another type of arthropod with primitive eyes on stalks that projected from its head shield.

The new anomalocarid has been named Stanleycaris hirpex in honour of the Stanley Glacier.  All these creatures inhabited an area of warm, equatorial sea just off the coast of the landmass known as Laurentia.

Anomalocarids

Anomalocarids were a group of predatory arthropods, that have no extant relatives.  Some of these marine hunters were up to ten times bigger than any other animal living at the time, with some specimens estimated to be approximately 2 metres long.  They had large, rotund eyes on stalks and under the head, a circular shaped mouth with sharp interlocking plates that could crush the exoskeletons of Trilobites and other marine creatures.

The curled front appendages had sharp spikes on them and scientists believe that these pincer-like organs were used to grab prey.  The name Anomalocaris (pronounced An-oh-mal-low-kar-is) means “odd shrimp”.

The Stanley Glacier fossils were not formed in the presence of a submarine cliff.  This suggests that creatures can be fossilised in amazing detail under other geological conditions, giving rise to the possibility of many more Cambrian fossil sites with soft body preservation being found.

The research team state:

“We consider it likely that future exploration and study will continue to yield new taxa from the “thin” Stephen Formation, which is exposed over a broader area regionally than the “thick” Stephen Formation.”

To read more about amazing discoveries and the work of the Royal Ontario Museum: Discoveries from the Cusp of the Phanerozoic.