Ancient reptiles detached tails to escape

This 2015 video is called Treasure Trove of Permian Fossils Discovered | Prehistoric News.

From the University of Toronto in Canada:

Ancient reptile Captorhinus could detach its tail to escape predator’s grasp

March 6, 2018

Summary: A new study shows how a group of small reptiles who lived 289 million years ago could detach their tails to escape the grasp of their would-be predators — the oldest known example of such behavior.

Imagine that you’re a voracious carnivore who sinks its teeth into the tail of a small reptile and anticipates a delicious lunch, when, in a flash, the reptile is gone and you are left holding a wiggling tail between your jaws.

A new study by the University of Toronto Mississauga research team led by Professor Robert Reisz and PhD student Aaron LeBlanc, published March 5 in the open source journal, Scientific Reports, shows how a group of small reptiles who lived 289 million years ago could detach their tails to escape the grasp of their would-be predators — the oldest known example of such behaviour. The reptiles, called Captorhinus, weighed less than 2 kilograms and were smaller than the predators of the time. They were abundant in terrestrial communities during the Early Permian period and are distant relatives of all the reptiles today.

As small omnivores and herbivores, Captorhinus and its relatives had to scrounge for food while avoiding being preyed upon by large meat-eating amphibians and ancient relatives of mammals. “One of the ways captorhinids could do this,” says first author LeBlanc, “was by having breakable tail vertebrae.” Like many present-day lizard species, such as skinks, that can detach their tails to escape or distract a predator, the middle of many tail vertebrae had cracks in them.

It is likely that these cracks acted like the perforated lines between two paper towel sheets, allowing vertebrae to break in half along planes of weakness. “If a predator grabbed hold of one of these reptiles, the vertebra would break at the crack and the tail would drop off, allowing the captorhinid to escape relatively unharmed,” says Reisz, a Distinguished Professor of Biology at the University of Toronto Mississauga.

The authors note that being the only reptiles with such an escape strategy may have been a key to their success, because they were the most common reptiles of their time, and by the end of the Permian period 251 million years ago, captorhinids had dispersed across the ancient supercontinent of Pangaea. This trait disappeared from the fossil record when Captorhinus died out; it re-evolved in lizards only 70 million years ago.

They were able to examine more than 70 tail vertebrae — both juveniles and adults — and partial tail skeletons with splits that ran through their vertebrae. They compared these skeletons to those of other reptilian relatives of captorhinids, but it appears that this ability is restricted to this family of reptiles in the Permian period.

Using various paleontological and histological techniques, the authors discovered that the cracks were features that formed naturally as the vertebrae were developing. Interestingly, the research team found that young captorhinids had well-formed cracks, while those in some adults tended to fuse up. This makes sense, since predation is much greater on young individuals and they need this ability to defend themselves.

This study was possible thanks to the treasure trove of fossils available at the cave deposits near Richards Spur, Oklahoma.


Carboniferous-Permian plant extinction harmed amphibians, helped reptiles

This video says about itself:

30 March 2015

Dave and Palaeo After Dark’s James explore the Carboniferous forests in the ‘Carboniferous Forest Simulator‘!

This fantastic software is free for educational, museum or personal use. We really need to get our full support behind this project!

The programme, in its ‘alpha testing’ stage can be downloaded here.

Details of the development of the project can be found here.

From the University of Birmingham in England:

Rainforest collapse 307 million years ago impacted the evolution of early land vertebrates

February 7, 2018

Researchers at the University of Birmingham have discovered that the mass extinction seen in plant species caused by the onset of a drier climate 307 million years ago led to extinctions of some groups of tetrapods, the first vertebrates to live on land, but allowed others to expand across the globe. This research is published today (7th February 2018) in the journal Proceedings of the Royal Society B.

The Carboniferous and Permian periods (358 — 272 million years ago) were critical intervals in the evolution of life on land. During the Carboniferous Period North America and Europe lay in a single land mass at the equator which was covered by dense tropical rainforests. These rainforests flourished because of the warm humid climate, providing an ideal habitat for early tetrapods (vertebrates with four limbs), allowing them to diversify into a variety of species.

But towards the end of this period a major global environment change took place — just as the number of tetrapod species began to increase, the rainforests started to disappear. The climate became much drier causing the mass extinction of many species within the dominant plant groups, such as horsetails and club mosses. Despite this being a catastrophic event for plants, it has been unclear how this affected the early tetrapod community.

Previous attempts to estimate the diversity changes during this period have been hindered by the fossil record, which has not been sampled equally in different time intervals or geographic areas. To fill these gaps in the data, the Birmingham researchers compiled a new dataset from the Paleobiology Database and used advanced statistical methods to estimate diversity and biogeographic changes.

The results of the study show that tetrapod diversity decreased after the rainforest collapse and the onset of drier conditions, largely due to the reduction in suitable habitats for amphibians which needed wet environments to survive.

However they also found that after the rainforest collapse surviving tetrapod species began to disperse more freely across the globe, colonising new habitats further from the equator. Many of these survivors were early amniotes, such as early reptiles, whose generally larger size relative to early amphibians allowed them to travel longer distances, and their ability to lay eggs meant they were not confined to watery habitats.

Emma Dunne, from the University of Birmingham’s School of Geography, Earth and Environmental Sciences, said: ‘This is the most comprehensive survey ever undertaken on early tetrapod evolution, and uses many newly developed techniques for estimating diversity patterns of species from fossil records, allowing us greater insights into how early tetrapods responded to the changes in their environment.’

Dunne continued: ‘We now know that the rainiforest collapse was crucial in paving the way for amniotes, the group which ultimately gave rise to modern mammals, reptiles and birds, to become the dominant group of land vertebrates during the Permian period and beyond.’

Ancient amphibians’ teeth, new study

This video says about itself:

23 January 2016

The first major groups of amphibians developed in the Devonian period, around 370 million years ago, from lobe-finned fish which were similar to the modern coelacanth and lungfish. These ancient lobe-finned fish had evolved multi-jointed leg-like fins with digits that enabled them to crawl along the sea bottom.

Some fish had developed primitive lungs to help them breathe air when the stagnant pools of the Devonian swamps were low in oxygen. They could also use their strong fins to hoist themselves out of the water and onto dry land if circumstances so required.

Eventually, their bony fins would evolve into limbs and they would become the ancestors to all tetrapods, including modern amphibians, reptiles, birds, and mammals. Despite being able to crawl on land, many of these prehistoric tetrapodomorph fish still spent most of their time in the water. They had started to develop lungs, but still breathed predominantly with gills.

From the University of Toronto in Canada:

Ancient amphibian had mouthful of teeth ready to grab you

September 15, 2017

The idea of being bitten by a nearly toothless modern frog or salamander sounds laughable, but their ancient ancestors had a full array of teeth, large fangs and thousands of tiny hook-like structures called denticles on the roofs of their mouths that would snare prey, according to new research by paleontologists at the University of Toronto Mississauga (UTM).

In research published online in a recent issue of PeerJ, an open access journal, Professor Robert Reisz, Distinguished Professor of Paleontology at UTM, explains that the presence of such an extensive field of teeth provides clues to how the intriguing feeding mechanism seen in modern amphibians was also likely used by their ancient ancestors.

They believe that the tooth-bearing plates, ideally suited for holding on to prey, such as insects or smaller tetrapods, may have facilitated a method of swallowing prey items via retraction of the eyeballs into the mouth, as some amphibians do today.

In many vertebrates, ranging from fish to early synapsids (ancestors of mammals), denticles are commonly found in dense concentrations on the bones of the hard palate (roof of the mouth). However, in one group of tetrapods, temnospondyls (which are thought to be the ancestors of modern amphibians) these denticles were also found on small, bony plates that filled the large soft part of the palate. The entire roof of the mouth was covered with literally thousands of these tiny teeth that they used to grab prey. Since these toothy plates were suspended in soft tissue, they are often lost or scattered during fossilization.

Denticles are significantly smaller than the teeth around the margin of the mouth — on the order of dozens to a couple hundred microns in length. They are actually true teeth, rather than just protrusions in the mouths of these tetrapods, says Reisz and his colleagues, Bryan Gee and Yara Haridy, both graduate students in paleontology.

“Denticles have all of the features of the large teeth that are found on the margin of the mouth,” says Reisz. “In examining tetrapod specimens dating back ~289 million years, we discovered that the denticles display essentially all of the main features that are considered to define teeth, including enamel and dentine, pulp cavity and peridontia.”

In reaching these conclusions, the researchers analyzed [Permian age] specimens unearthed from the fossil-rich Dolese Brothers Limestone Quarry near Richards Spur, Oklahoma. They were extraordinarily well preserved, making them ideal candidates for study.

The researchers extracted and isolated the denticle-bearing plates, created thin section slides and examined them under the microscope — no small feat since denticles on this animal were only about 100 microns long.

Reisz and his graduate students suggest that the next big question relates to evolutionary changes to the overall abundance of teeth: if these ancient amphibians had an astonishing number of teeth, why have most modern amphibians reduced or entirely lost their teeth?

Brittle stars fossils discovery in Australia

This video says about itself:

13 August 2017

Australia was a different place 275 million years ago – wild storms surged through icy seas, and marine animals lived a tenuous existence. But brittle stars had a survival strategy.

From the University of Cambridge in England:

Meadow of dancing brittle stars shows evolution at work

August 14, 2017

Newly-described fossil shows how brittle stars evolved in response to pressure from predators, and how an ‘evolutionary hangover’ managed to escape them.

Researchers have described a new species of brittle star, which are closely related to starfish, and showed how these sea creatures evolved in response to the rise of shell-crushing predators during the late Palaeozoic Era. The results, reported in the Journal of Systematic Palaeontology, also suggest that brittle stars evolved new traits before the largest mass extinction event in Earth’s history, and not after, as was the case with many other forms of life.

A fossilised ‘meadow’ of dancing brittle stars — frozen in time in the very spot that they lived — was found in Western Australia and dates from 275 million years ago. It contains several remarkably preserved ‘archaic’ brittle stars, a newly-described genus and species called Teleosaster creasyi. They are the last known complete brittle stars of their kind, an evolutionary hangover pushed to the margins of the world’s oceans by the threat from predators.

The researchers, from the University of Cambridge, suggest that while other species of brittle stars evolved in response to predators such as early forms of rays and crabs, these archaic forms simply moved to where the predators weren’t — namely the seas around Australia, which during the Palaeozoic era was pushed up against Antarctica. In these cold, predator-free waters, the archaic forms were able to grow much larger, and lived at the same time as the modern forms of brittle star, which still exist today.

Brittle stars consist of a central disc and five whip-like appendages, which are used for locomotion. They first appear in the fossil record about 500 million years ago, in the Ordovician Period, and today there are about 2,100 different species, mostly found in the deep ocean.

Early brittle stars were just that: brittle. During the Palaeozoic Era, when early shell-crushing predators first appeared, brittle stars made for easy prey. At this point, a split in the evolutionary tree appears to have occurred: the archaic, clunky brittle stars moved south to polar waters, while the modern form first began to emerge in response to the threat from predators, and was able to continue to live in the warmer waters closer to the equator. Both forms existed at the same time, but in different parts of the ocean.

“The threat from predation is an under-appreciated driver of evolutionary change,” said study co-author Dr Kenneth McNamara of Cambridge’s Department of Earth Sciences. “As more predators began to appear, the brittle stars started to evolve more flexible bodies, which enabled them to either burrow into the sediment, or to move more rapidly to escape.”

About 250 million years ago, the greatest mass extinction in Earth’s history — the Permian-Triassic extinction event, or the “Great Dying” — occurred. More than 90% of marine species and 70% of terrestrial species went extinct, and as a result, most surviving species underwent major evolutionary changes as a result.

“Brittle stars appear to have bucked this trend, however,” said co-author Dr Aaron Hunter, a visiting postdoctoral researcher in the Department of Earth Sciences. “They seem to have evolved before the Great Dying, into a form which we still see today.”

Meadows of brittle stars and other invertebrates such as sea urchins and starfish can still be seen today in the seas around Antarctica. As was the case during the Palaeozoic, the threat from predators is fairly low, although the warming of the Antarctic seas due to climate change has been linked to the recent arrival of armies of king crabs, which represent a real threat to these star-filled meadows.

Brittle Stars inspire new generation of robots able to adapt to physical damage: here.

Scientists have discovered the first evidence that brittle stars living in vibrant coral reefs use thousands of light sensors to navigate their way through their complex environments: here.

Special Permian beetle fossil discovered in Australia

These are 3-D habitual and environmental reconstructions of Ponomarenkia belmonthensis restored after linedrawing of the holotype and 2-D reconstruction. The plant is Australian cycadophyt Lepidozamia hopei from the Botanical Garden of Jena University. Credit: © Evgeny V. Yan/FSU Jena

From the Friedrich-Schiller-Universitaet Jena in Germany:

300 million-year-old ‘modern’ beetle from Australia reconstructed

July 24, 2017

He’s Australian, around half a centimetre long, fairly nondescript, 300 million years old, and he’s currently causing astonishment among both entomologists and palaeontologists. The discovery of a beetle from the late Permian period, when even the dinosaurs had not yet appeared on the scene, is throwing a completely new light on the earliest developments in this group of insects. The reconstruction and interpretation of the characteristics of Ponomarenkia belmonthensis was achieved by Prof. Dr Rolf Beutel and Dr Evgeny V. Yan of Friedrich Schiller University Jena (Germany). They have published this discovery together with beetle researcher Dr John Lawrence and Australian geologist Dr Robert Beattie in the current issue of the Journal of Systematic Palaeontology. It was Beattie who discovered the only two known fossilised specimens of the beetle in former marshland in Belmont, Australia.

“Beetles, which with nearly 400,000 described species today make up almost one-third of all known organisms, still lived a rather shadowy and cryptic existence in the Permian period,” explains Jena zoologist Beutel. “The fossils known to date have all belonged to an ancestral beetle lineage, with species preferring narrow spaces under bark of coniferous trees. They exhibit a whole series of primitive characteristics, such as wing cases (elytra) that had not yet become completely hardened or a body surface densely covered with small tubercles.”

Earliest form of the modern beetle

In contrast, the species that has now been discovered, assigned to the newly introduced family Ponomarenkiidae, can be identified as a modern beetle, in spite of its remarkable age. Modern characteristics are the antennae resembling a string of beads, antennal grooves, and the unusually narrow abdomen, tapering to a point. What is more, unlike previously known Permian beetles, the wing cases are completely hardened, the body’s surface is largely smooth, and the thoracic segments responsible for locomotion show modern features, notes insect palaeontologist Yan. In addition, it appears that this little beetle had stopped living under tree bark, the habitat favoured by its contemporaries, and had adopted a much more exposed lifestyle on plants. A significant fact is that, due to its unorthodox combination of ancestral and modern characteristics, this genus does not fit in any of the four suborders of beetles that still exist, which is why Yan and Beutel have given it the nickname Bad Boy. “Ponomarenkia belmonthensis shows above all that the first major events of radiation in the evolution of beetles took place before the Permian-Triassic mass extinction,” says Rolf Beutel. Beetles as a whole survived this dramatic event, which saw the acidification of the seas and major volcanic eruptions, considerably better than most other groups of organisms, presumably because of their terrestrial life style and hardened exoskeleton. However, the Bad Boy ran out of luck, as there are no more traces of its existence in the Mesozoic era.

Name honours eminent palaeontologist

The Jena researchers dedicated the genus and family to Moscow palaeontologist Prof. Alexander G. Ponomarenko. He has had a strong influence on beetle palaeontology for decades and supervised Dr Evgeny V. Yan’s doctorate. Yan obtained his doctorate from the Russian Academy of Sciences, spent five years as a postdoc at the Chinese Academy of Sciences in Nanjing, and since June 2016 he has done research at the Institute of Systematic Zoology and Evolutionary Biology with Phyletic Museum of the University of Jena as a guest researcher funded by the Alexander von Humboldt Foundation. It is Yan’s elaborate reconstructions on the computer that have provided the precise insights into Ponomarenkia belmonthensis.

In the first stage, some 40 photographs were taken of the two specimens, which were available as impressions on stone. “With this series of photographs an accurate 2D reconstruction was possible, with which we were able to correct for deformations in the original fossil. This allowed us to get closer to the actual beetle,” explains Dr Yan. Based on precise drawings and with the help of a special computer program that is also used for animation and computer games, a very informative 3D model was created. “The 3D reconstruction also enables us to draw conclusions about the way the beetle moved and lived,” the palaeontologist adds. He has developed this method of visualisation, as well as the analytical process in which he also includes hypothetical ancestors of the beetle, since his arrival in Jena. “We have already been able to apply this process to three newly discovered ancient beetle species,” Prof. Beutel is happy to report. “In this way, we have made significant steps towards deciphering the earliest stages in the evolution of an extremely successful genus of animals.”

Big fish, little fish in Permian-Triassic mass extinction

This video says about itself:

The Permian-Triassic extinction event, informally known as the Great Dying, was an extinction event that occurred 252 million years ago, forming the boundary between the Permian and Triassic geologic periods, as well as the Paleozoic and Mesozoic eras.

It is the Earth’s most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It is the only known mass extinction of insects. Some 57% of all families and 83% of all genera became extinct. Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event, possibly up to 10 million years.

Catastrophe by Tony Robinson (2008).

From the University of Bristol in England:

Size not important for fish in the largest mass extinction of all time

June 30, 2017

Understanding modern biodiversity and extinction threats is important. It is commonly assumed that being large contributes to vulnerability during extinction crises.

However, researchers from the University of Bristol and the Chengdu Center of the China Geological Survey, have found that size played no role in the extinction of fish during the largest mass extinction of all time.

The study focused on the evolution of bony fishes during the Permian-Triassic mass extinction 252 million years ago. During this crisis, as many as 90 percent of all species on Earth were killed by massive climate change triggered by huge volcanic eruptions in Russia.

The erupted gases led to worldwide acid rain and atmospheric warming of as much as 20 degrees centigrade. This killed plants, and soil was stripped by rainfall and washed into the sea. Oceans were also heated and life fled from the tropics.

It was expected that a key feature in extinction would have been body size: the large animals would suffer heat and starvation stress first. However, in the new paper, published in Palaeontology, it is shown that larger fish were no more likely to go extinct than small fish.

The study used a detailed summary of all information on fossil fish through a span of over 100 million years, from well before to well after the disaster. Body size information was identified for over 750 of these fishes, and multiple calculations were carried out to allow for variations in the shape of the evolutionary tree and the exact dating of all the species. The result was clear — body size did not provide any advantages or disadvantages to fish during the crisis.

Lead researcher Dr Mark Puttick from the Natural History Museum and University of Bristol’s School of Earth Sciences, explained: “These results continue the trend of recent studies that suggest body size played no role in determining which species survive or go extinct. This is the opposite result we would expect, but provides increasing support for previous studies that show body size plays no role in extinction selectivity.”

The team explored the largest dataset used in an analysis of this type and applied a range of computational evolutionary models to understand these patterns in deep time. The models take account of uncertainties in the quality of the fossil data and the reconstructed evolutionary tree, and the result was clear.

Professor Michael Benton, also from the University of Bristol, added: “These are exciting results. What is important also is that we were able to deploy new methods in the study that take greater account of uncertainties.

“The methods are based around a detailed evolutionary tree so, unlike most previous work in the field, we paid attention to the relationships of all the species under consideration.”

Professor Shixue Hu, leader of the China Geological Survey: “It’s great to see this new analytical work. We were able to include many new fossils from our exceptional biotas in China, and we can see the full impact of the extinction and the subsequent recovery of life during the Triassic.”

Lead author Dr Dunhill, from the School of Earth and Environment at Leeds, said: “While the Late Triassic mass extinction had a big impact on the overall number of marine species, there was still enough diversity among the remaining species that the marine ecosystem was able to function in the same way it had before”: here.

An international team led by researchers from the Evolutionary Studies Institute (ESI) at the University of the Witwatersrand, Johannesburg, has obtained an age from rocks of the Great Karoo that shed light on the timing of a mass extinction event that occurred around 260 million years ago. This led to the disappearance of a diverse group of early mammal-like reptiles called dinocephalians, which were the largest land-living animals of the time: here.

The study, conducted by Dr Juan Carlos Cisneros and his co-researchers of the University of the Witwatersrand examined the skulls of mammal relatives from the Permian Period. While saber teeth are commonly associated with a group of Ice Age felines and the saber-tooth reptile gorgonopsians, one peculiar species known as Tiarajudens eccentricus also possessed protruding canines despite its apparent herbivory: here.

Variation in the recovery of tetrapods after the Permian extinction opened the door for dinosaurs and mammals: here.

During the late Permian, the equator was dry and desert-like, yet surprisingly a hotspot for biodiversity, new paleontological research shows. Similarly to modern rainforests, equator ecosystems were home a unique diversity of species, including those both anciently and newly evolved. After the late Permian extinction, this diversity was decimated, and the climate change event that triggered an extinction back then is informative as we move forward with protecting our planet’s species diversity: here.

Ancient ozone holes may have sterilized forests 252 million years ago. Barren trees could have collapsed food webs, leading to Earth’s greatest mass extinction. By Carolyn Gramling, 7:00am, February 12, 2018.

Mammal-like reptile’s brain, new research

Kawingasaurus fossilis at Museum of Paleontology, Tuebingen, Germany

From the Universität Duisburg-Essen in Germany:

A skull with history: A fossil sheds light on the origin of the neocortex

June 26, 2017

According to a recent study an early relative of mammals already possessed an extraordinarily expanded brain with a neocortex-like structure. This has been discovered by Michael Laaß from the Institute of General Zoology at the University of Duisburg-Essen (UDE).

Today, mammals possess large and efficient brains. But, what was the bauplan of the brain of their far relatives, the therapsids? When and why evolved the neocortex?

For his doctoral thesis the palaeontologist Michael Laaß invesitgated a ca. 255 million years old fossil skull of the therapsid Kawingasaurus fossilis in collaboration with Dr. Anders Kaestner from the Paul Scherrer Institute in Switzerland by means of neutron tomography and reconstructed the internal cranial anatomy in 3D.

The results were amazing: The relative brain volume of Kawingasaurus was about two or three-times larger than in other non-mammalian therapsids. Laaß: “Interestingly, Kawingasaurus already possessed a large forebrain with two distinct cerebral hemispheres.” Obviously, a neocortex-like structure at the forebrain similar to the mammalian neocortex was present in this animal.

Why is this brain structure evolved in Kawingasaurus? “Kawingasaurus was a burrower and special sensory adaptations were crucial for life under ground,” explained the UDE scientist. For example, this therapsid possessed frontally placed eyes, which were probably useful for binocular vision in dimlight environments as it is known from modern cats and owls. Furthermore, extremely ramified trigeminal nerve endings penetrated the snout, which might be an indication for a well developed sense of touch. The inner ear vestibules were also very large, which suggests that Kawingasaurus was well adapted to detect seismic vibrations from the ground.

Laaß: “These special sensory adaptaions also required a more efficient neural processing of the brain than in other therapsids.” It seems reasonable that these special adaptations of the sense organs and the brain to underground life triggered the expansion of the brain. Interestingly, a similar scenario for the origin of the neocortex has been also proposed for early mammals. Consequently, the recent study at the UDE supports this hypothesis.

Moreover, the new discovery also shows that a neocortex-like structure already developed in the therapsid Kawingasaurus about 25 million years earlier before the emergence of the first mammals. However, Kawingasaurus was not a direct ancestor of mammals. Consequently, neocortex-like structures evolved several times independently in pre-mammalian and mammalian evolution.