‘Mass extinctions killed less wildlife than thought’

This video from Britain says about itself:

Catastrophe – The Permian Extinction

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.

Presented by Tony Robinson.

Originally published in 2008 by Channel 4

That was the prevalent view in 2008. And now …

From the Proceedings of the National Academy of Sciences of the United States of America:

Estimates of the magnitudes of major marine mass extinctions in earth history

Steven M. Stanley

October 3, 2016


This paper shows that background extinction definitely preceded mass extinctions; introduces a mathematical method for estimating the amount of this background extinction and, by subtracting it from total extinction, correcting estimates of losses in mass extinctions; presents a method for estimating the amount of erroneous backward smearing of extinctions from mass extinction intervals; and introduces a method for calculating species losses in a mass extinction that takes into account clustering of losses. It concludes that the great terminal Permian crisis eliminated only about 81% of marine species, not the frequently quoted 90–96%. Life did not almost disappear at the end of the Permian, as has often been asserted.


Procedures introduced here make it possible, first, to show that background (piecemeal) extinction is recorded throughout geologic stages and substages (not all extinction has occurred suddenly at the ends of such intervals); second, to separate out background extinction from mass extinction for a major crisis in earth history; and third, to correct for clustering of extinctions when using the rarefaction method to estimate the percentage of species lost in a mass extinction. Also presented here is a method for estimating the magnitude of the Signor–Lipps effect, which is the incorrect assignment of extinctions that occurred during a crisis to an interval preceding the crisis because of the incompleteness of the fossil record.

Estimates for the magnitudes of mass extinctions presented here are in most cases lower than those previously published. They indicate that only ∼81% of marine species died out in the great terminal Permian crisis, whereas levels of 90–96% have frequently been quoted in the literature. Calculations of the latter numbers were incorrectly based on combined data for the Middle and Late Permian mass extinctions. About 90 orders and more than 220 families of marine animals survived the terminal Permian crisis, and they embodied an enormous amount of morphological, physiological, and ecological diversity. Life did not nearly disappear at the end of the Permian, as has often been claimed.

Mid-Permian extinction of animals, new study

This 2013 video says about itself:

Animal Armageddon The Great Dying – Episode 5

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.

Researchers have variously suggested that there were from one to three distinct pulses, or phases, of extinction. There are several proposed mechanisms for the extinctions; the earlier phase was likely due to gradual environmental change, while the latter phase has been argued to be due to a catastrophic event. Suggested mechanisms for the latter include large or multiple impact events, increased volcanism, coal/gas fires and explosions from the Siberian Traps, and sudden release of methane from the sea floor; gradual changes include sea-level change, increasing aridity, and a shift in ocean circulation driven by climate change.

From the Geological Society of America:

15 April 2015

New evidence adds the Capitanian extinction to the list of major extinction crises

Boulder, Colo., USA – Since the Cambrian Explosion, ecosystems have suffered repeated mass extinctions, with the “Big 5” crises being the most prominent. Twenty years ago, a sixth major extinction was recognized in the Middle Permian (262 million years ago) of China, when paleontologists teased apart losses from the “Great Dying” at the end of the period. Until now, this Capitanian extinction was known only from equatorial settings, and its status as a global crisis was controversial.

David P.G. Bond and colleagues provide the first evidence for severe Middle Permian losses amongst brachiopods in northern paleolatitudes (Spitsbergen). Their study shows that the Boreal crisis coincided with an intensification of marine oxygen depletion, implicating this killer in the extinction scenario.

The widespread loss of carbonates across the Boreal Realm also suggests a role for acidification. The new data cements the Middle Permian crisis’s status as a true “mass extinction.” Thus the “Big 5” extinctions should now be considered the “Big 6.”

An abrupt extinction in the Middle Permian (Capitanian) of the Boreal Realm (Spitsbergen) and its link to anoxia and acidification: David P.G. Bond et al., University of Hull, Hull, UK. Published online ahead of print on 14 Apr. 2015; http://dx.doi.org/10.1130/B31216.1. This article is OPEN ACCESS (available for free online).

Ancient tree rings from the Permian period record a roughly 11-year cycle of wet and dry periods, climate fluctuations caused by the ebbing and flowing of solar activity, researchers propose January 9 in Geology. The discovery would push back the earliest evidence of today’s 11-year solar cycle by tens of millions of years: here.

Dimetrodon ancient reptile, new discoveries

This dimetrodon video is called Paleoworld– Tale Of A Sail (Part 1).

From Sci-News.com:

Dimetrodon Had Steak-Knife Teeth, Scientists Say

Feb 10, 2014

An international team of paleontologists suggests dimetrodon – a 4-m-long prehistoric reptile that lived during the early Permian period, between 295 million and 272 million years ago, and went extinct about 40 million years before the appearance of first dinosaurs – was the first terrestrial vertebrate to develop serrated ziphodont teeth.

Dimetrodon was the top of the terrestrial food chain in the early Permian and is considered to be the forerunner of mammals.

According to a new study reported in the journal Nature Communications, dimetrodons had a diversity of previously unknown tooth structures and were also the first terrestrial vertebrate to develop cusps – teeth with raised points on the crown, which are dominant in mammals.

The study also suggests ziphodont teeth were confined to later species of dimetrodon, indicating a gradual change in feeding habits.

“This research is an important step in reconstructing the structure of ancient complex communities,” said senior author Prof Robert Reisz from the University of Toronto Mississauga.

“Teeth tell us a lot more about the ecology of animals than just looking at the skeleton.”

“We already know from fossil evidence which animals existed at that time but now with this type of research we are starting to piece together how the members of these communities interacted.”

Prof Reisz and his co-author, Kirstin Brink from the University of Toronto Mississauga, studied the changes in dimetrodon teeth across 25 million years of evolution.

The analysis indicated the changes in tooth structure occurred in the absence of any significant evolution in skull morphology. This indicates a change in feeding style and trophic interactions.

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Niger Permian reptile fossil discovery

After the South African discovery of an early Triassic amphibian and a mammal-like reptile together … now a discovery from a few million years earlier, more to the north in Africa.


From the BBC:

24 June 2013 Last updated at 19:02 GMT

A bizarre reptile with knobbly growths on its head roamed a vast, isolated desert about 260 million years ago, researchers say.

New fossils from northern Niger in Africa have been described in the Journal of Vertebrate Paleontology.

The distinctive creature belongs to a new genus of pareiasaur – plant-eating creatures that flourished during the Permian period.

The cow-sized specimen has been named Bunostegos, which means “knobby roof”.

During Permian times, the Earth was dominated by a single supercontinent called Pangaea.

Animal and plant life dispersed broadly across the land, as documented by identical fossil species found on multiple modern continents.

But the new research by an international team supports the idea that there was an isolated desert in the middle of Pangaea with distinctive animals.

Most pareiasaurs had bony knobs on their skulls, but Bunostegos sported the largest, most bulbous ones ever seen in this group, which were common in the Middle and Late Permian, about 266-252 million years ago.

In life, these were probably skin-covered horns like those on the heads of modern giraffes.

“We can’t say for sure, but it is most likely that the bony knobs on the skull of pareiasaurs did not serve a protective function,” Dr Linda Tsuji from the University of Washington in Seattle told BBC News.

“They vary quite markedly in size and shape between different species, with some species lacking prominent knobs entirely, so I think that they were purely ornamental. The most probable use was for inter-specific (between species) or intra-specific (within species) recognition.”

Dr Tsuji and colleagues performed an analysis showing that Bunostegos was actually more closely related to older and more primitive pareiasaurs.

This led them to the conclusion that its genealogical lineage had been isolated for millions of years.

Climatic conditions may have conspired to corral Bunostegos – along with several other reptiles, amphibians, and plants – and keep them constrained to the central, arid area of the supercontinent.

“Our work supports the theory that central Pangea was climatically isolated, allowing a unique relict fauna to persist into the Late Permian,” said Christian Sidor, another author of the paper.

This surprised the scientists because areas outside this central region show fossil evidence of regular faunal interchange.

Geological data show that central Pangaea was extremely dry, discouraging some animals from passing through, while keeping those within from venturing out.

The long period of isolation under these parched conditions gave Bunostegos lineage time to evolve its unique anatomical features.

Much of what was once central Pangaea remains to be explored by palaeontologists.

“It is important to continue research in these under-explored areas,” said Dr Tsuji.

“The study of fossils from places like northern Niger paints a more comprehensive picture of the ecosystem during the Permian era.”

See also here.

To Longyearbyen, Svalbard, Arctic

This video is about a plane landing at LYR airport, Longyearbyen, Svalbard, in May 2007.

2 June 2013.

I have been to the Antarctic.

But I had never been to the high Arctic so far. The closest I came were the Lofoten islands of Norway, and Iceland, both near the Arctic circle.

Now, however, to Svalbard. This Arctic archipelago is about halfway between northern Norway and the North Pole. Outside Norway, the islands are often called Spitsbergen; in Norwegian, the name of the largest island.

First, our plane went to Oslo, the capital of Norway.

After some hours waiting, we transferred to a smaller plane.

At 10pm, it passed the Arctic circle, flying near Bodø in northern Norway.

23:05: we pass Bear Island, about half way between Svalbard and continental Norway. Officially, Bear Island is the southernmost island of the Svalbard archipelago. It is uninhabited now, except for a meteorological station.

South western Spitsbergen from the air, 2 June 2013

Then, the plane reached the mountains of the west coast of Spitsbergen island.

South western Spitsbergen mountains from the air, 2 June 2013

This video is called Landing at Longyearbyen / Svalbard lufthavn (LYR) on 8 April 2009 on a flight from Ny-Ålesund.

Almost at midnight of 2 June, we landed at the airport of Longyearbyen, the capital (basically: the only sizable village) of Svalbard.

We drove from the airport to Longyearbyen village.

It is Arctic summer. So, the sun never sets now.

Svalbard is one of not so many countries where there has never been a visit to Dear Kitty. Some blog yet. Not that surprising: only 2,500 people live there, not all of them fanatical Internauts.

During the next days, there were will be photos of birds, other wildlife of Svalbard and other sides of Svalbard on this blog.

About Svalbard prehistory:

Bryozoans from the Lower Permian Treskelodden and Wordiekammen formations of southern and central Spitsbergen respectively, Svalbard, have been studied. Twenty species are identified, including one new genus, Toulapora gen. nov., with Toulapora svalbardense as type species and one new species, Ascopora birkenmajeri sp. nov. The taxonomic composition is typical Lower Permian, with species in common with Timan−Pechora and the Urals (Russia) and Ellesmere Island (the Canadian Arctic). Growth habits reflect a moderately to deeper shelf environment.

How turtles got their shells

Eunotosaurus africanus

By Roxanne Palmer:

Turtle Shell Origin Story Gets New Chapter Thanks To Fossil Reptile

May 30 2013 12:55 PM

Rudyard Kipling’s fanciful “Just So Stories” have offered explanations for how the leopard got his spots and how the camel got his hump. Kipling didn’t offer an origin story for the turtle’s shell, but scientists have now come to the rescue.

In a new paper published in the journal Current Biology, researchers led by Yale University and Smithsonian Institution researcher Tyler Lyson present the earliest evidence yet for how some ancient reptiles turned into swimming tanks.

The turtle’s shell is a unique specimen of evolution. Other animals with shells usually have ones made from bony scales on the outsides of their bodies – like the crocodile, whose skin is dotted with thick bony plates called osteoderms. But a turtle’s shell is made from the fusion of more than 50 bones, including parts of the pelvis, ribs and vertebrae.

To get a better picture of how the turtle shell was made, Lyson and his colleagues studied an ancient South African reptile called Eunotosaurus africanus, which hails from about 260 million years ago. Scientists have found fossils of other turtle ancestors, but these ones had either fully developed shells. In 2008, Chinese scientists uncovered the remains of the 220 million-year-old Odontochelys semitestacea, which had a complete shell on its belly side, but only a partially developed shell on the back. The new specimen goes back even earlier.

“Eunotosaurus neatly fills an approximately 30-55-million year gap in the turtle fossil record,” Lyson said in a statement. “There are several anatomical and developmental features that indicate Eunotosaurus is an early representative of the turtle lineage; however, its morphology is intermediate between the specialized shell found in modern turtles and primitive features found in other vertebrates.”

The fossil shares several characteristics with modern turtles, including broad ribs and a lack of intercostal muscles, which run between the ribs and which provide support and movement for the chest wall.

“The reason, I think, that more animals don’t form a shell via the broadening and eventually suturing together of the ribs is that the ribs of mammals and lizards are used to help ventilate the lungs,” Lyson says. “If you incorporate your ribs into a protective shell, then you have to find a new way to breathe!”

Since their shells don’t let modern turtles breathe by expanding and contracting their ribs, they have other methods. One part of the process is called “buccal pumping,” and it involves gulping air and pushing it into the lungs using movements of the throat. Turtles can also sometimes achieve a limited amount of respiration via the cloaca – hence the popular myth that turtles breathe through their rear ends. Some species of turtle have sacs called bursae on either side of the cloaca, with thin membranes that allow for gas exchange.

Most turtles don’t rely on their rear ends to breathe, but an Australian species called the Fitzroy River turtle has exploited this feature. This turtle can pump water in and out of the sacs near its cloaca and meet up to two-thirds of its oxygen needs this way.

Solving the mystery of how turtle breathing developed over time is the next research frontier for Lyson and his colleagues.

“It is clear that this novel lung ventilation mechanism evolved in tandem with the origin of the turtle shell,” he says.

SOURCE: Lyson et al. “Evolutionary Origin of the Turtle Shell.” Current Biology published online 30 May 2013.