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).

Big Triassic amphibian fossil discovery in Portugal


This video says about itself:

24 March 2015

Excavation in Portugal of giant Triassic fossil amphibian Metoposaurus algarvensis – Paleontology dig.

From Associated Press:

Researchers Find Fossil of ‘Super Salamander’ Species

LONDON — Mar 24, 2015, 11:01 AM ET

Fossil remains of a previously unknown species of a crocodile-like “super salamander” that grew as long as a small car and was a top predator more than 200 million years ago have been found in southern Portugal, researchers announced Tuesday.

The species grew up to two meters (six feet) in length and lived in lakes and rivers, University of Edinburgh researchers said.

The team said the species, given the name Metoposaurus algarvensis, was part of a wider group of primitive amphibians that were widespread at the time but became extinct. They are the ancestors of modern amphibians such as frogs, and are believed by paleontologists to have lived at the same time the dinosaurs began their dominance.

Steve Brusatte of the University of Edinburgh’s School of GeoSciences, who led the study, said the new species, which had hundreds of sharp teeth, is “weird compared to anything today.”

It was at the top of the food chain, feeding mainly on fish, but it was also a danger for newly appeared dinosaurs and mammals that strayed too near the water, Brusatte said.

The team says the find establishes that this group of amphibians lived in a more diverse geographic area than had been thought.

Andrew Milner, an expert on early amphibians at the Natural History Museum in London who was not involved in the study, said the find “is another piece of the picture.” The Portuguese site has “very good potential to give us more and different types of animal” from the Upper Triassic period, he added.

The dig in Portugal began in 2009 and took several years. The “super salamander” bones were uncovered in a half-meter thick layer of rock in a hillside that is “chock-full” of bones, Brusatte said. The team hopes to raise funds to continue excavating the site.

See also here.

The scientific description of this newly discovered species is here.

Pre-dinosaur carnivorous reptile discovery in Tanzania


This 2010 video says about itself:

Just testing out some software that records cursor movements. This is a Photoshop sketch of an extinct archosaur called a rauisuchian. They were related to crocodilians and distant cousins of the dinosaurs.

From Science, Space & Robots:

Partial Skel[e]ton of Ancient Croc-like Predator Species Discovered

Nundasuchus was a 9-foot long predator croc-like species that lived before the dinosaurs. It had steak knife-teeth and bony plates on its back. A partial skeleton of the species was discovered in 2007.

Nundasuchus songeaensis was named by Sterling Nesbitt, an assistant professor of geological sciences and member of the Virginia Tech paleontology team. Nesbitt says the name is “Swahili mixed with Greek.” Nunda means predator in Swahili and suchus refers to a crocodile in Greek. Songeaensis is named for the town of Songea where the creature’s bones were discovered.

Nesbitt says in a statement, “The reptile itself was heavy-bodied with limbs under its body like a dinosaur, or bird, but with bony plates on its back like a crocodilian.”

The fossil of Nundasuchus was found in southwestern Tanzania. The bones were in thousands of pieces and Nesbitt says over 1,000 hours were spent cleaning them and putting them together.

Nesbitt also says, “There’s such a huge gap in our understanding around the time when the common ancestor of birds and crocodilians was alive – there isn’t a lot out there in the fossil record from that part of the reptile family tree. This helps us fill in some gaps in the reptile family tree, but we’re still studying it and figuring out the implications.”

A research paper on the reptile can be found here in the Journal of Vertebrate Paleontology.

Posted on January 20, 2015

Triassic fossil reptile discovery in Dutch museum


This video says about itself:

21 March 2013

An overview of reptiles found in Triassic marine ecosystems.

Translated from daily De Gelderlander in the Netherlands:

Prehistoric marine reptile from Winterswijk ‘discovered’

January 9, 2015

ENSCHEDE WINTERSWIJK – Researchers from the Universities of Bonn and Zurich have recently ‘discovered’ a placodont in the collection of Museum TwentseWelle. The remains of the marine reptile were found in the late 1980’s in the quarry in Winterswijk by Gerben Diepenbroek from Varsseveld.

Diepenbroek gave his collection in 2008 to the museum in Enschede. Since then the collection is a subject of investigation by various universities in Europe.

According to Dennis Nieweg, nature department curator of TwentseWelle, it is a very special discovery. “Worldwide but a few placodonts are known.”

245 million years

The placodont is a marine reptile that lived some 245 million years ago in shallow waters, ”grazing’ seabeds looking for small animals such as sea urchins and crabs. According to Nieweg the discovery of this placodont improves our understanding of how the Netherlands was like 245 million years ago. The region around Winterswijk was under water then and was part of an inland sea covering the Netherlands.

The fossil remains of this sea reptile are again in Enschede after all investigations. Museum TwentseWelle shows them in a special showcase.

Triassic flying fish discovery in China


This video is called BBC Life – Flying Fish.

From Biology Letters:

A Middle Triassic thoracopterid from China highlights the evolutionary origin of overwater gliding in early ray-finned fishes

Guang-Hui Xu, Li-Jun Zhao, Chen-Chen Shen

January 2015

Abstract

Gliding adaptations in thoracopterid flying fishes represent a remarkable case of convergent evolution of overwater gliding strategy with modern exocoetid flying fishes, but the evolutionary origin of this strategy was poorly known in the thoracopterids because of lack of transitional forms.

Until recently, all thoracopterids, from the Late Triassic of Austria and Italy and the Middle Triassic of South China, were highly specialized ‘four-winged’ gliders in having wing-like paired fins and an asymmetrical caudal fin with the lower caudal lobe notably larger than the upper lobe.

Here, we show that the new genus Wushaichthys and the previously alleged ‘peltopleurid’ Peripeltopleurus, from the Middle Triassic (Ladinian, 235–242 Ma) of South China and near the Ladinian/Anisian boundary of southern Switzerland and northern Italy, respectively, represent the most primitive and oldest known thoracopterids.

Wushaichthys, the most basal thoracopterid, shows certain derived features of this group in the skull. Peripeltopleurus shows a condition intermediate between Wushaichthys and Thoracopterus in having a slightly asymmetrical caudal fin but still lacking wing-like paired fins. Phylogenetic studies suggest that the evolution of overwater gliding of thoracopterids was gradual in nature; a four-stage adaption following the ‘cranial specialization–asymmetrical caudal fin–enlarged paired fins–scale reduction’ sequence has been recognized in thoracopterid evolution. Moreover, Wushaichthys and Peripeltopleurus bear hooklets on the anal fin of supposed males, resembling those of modern viviparious teleosts. Early thoracopterids probably had evolved a live-bearing reproductive strategy.

South African Triassic carnivorous reptile Garjainia


This video says about itself:

Palaeodigs part 2 Giant amphibians and Early archosaurs

1 November 2013

Part 2/2 of a two part special recorded at excavations in Krasiejów, SW Poland. In this video I interview special guest Mateusz Tałanda about the amazing fossils found at Krasiejów. Sound and camera are a little poor, sorry.

From Laelaps blog today:

Big-Headed Carnivore a Sign of Triassic Recovery

by Brian Switek

I’ve spent much of my weekend writing about Jurassic World. I won’t rehash the details here – you can read those over at VICE – but it struck me how easy it is to talk about paleontology when everyone knows the animals you’re discussing. I don’t have to explain who Tyrannosaurus or Velociraptor were, and, from museums and movies, most everyone has some idea of what a dinosaur is.

But if Colin Trevorrow were directing Triassic World, my job would be a lot more difficult. With the exception of the first dinosaurs, and maybe the “armadillodiles“, most of the strange creatures that thrived between 252 and 200 million years ago don’t have common names or much presence at all in the public consciousness. So you’re going to have to bear with me for a second while I introduce you to Garjainia madiba.

Discovered in the 247 million year old rock of South Africa, and described by Natural History Museum, London paleontologist David Gower and colleagues in PLoS One, Garjainia madiba belonged to a group of carnivores called erythrosuchid archosauriforms. Let’s unpack that.

You know birds and crocodiles? They’re the two living lineages of a group of animals called archosaurs – the “ruling reptiles” – that, in turn, were part of a larger radiation of critters called archosauriforms. So lower down on the tree, close to the roots, there was a lineage of predatory archosauriforms called erythrosuchids to which Garjainia belonged. To give it a little more context, Garjainia madiba was archaic enough that, in hindsight, we can say it’s equally-closely-related to birds and crocodiles. Garjainia and its carnivorous kin evolved before that great split in the archosauriform family tree.

The animal that Gower and coauthors describe is not the first of its kind. The first species of Garjainia was described in 1958 from fossils uncovered in Russia. What makes the new species special is that it’s a little older and living in a different region, and, as long as you’re looking at the skull, it’s easy to tell the two species apart. The South African species, Garjainia madiba, has bulbous bosses of bone behind its eye and on its cheek that are lacking in the other species. Why this animal had these bumps isn’t yet clear – perhaps they were sign of maturity, differences between the sexes, or something else – but they’re among the traits that mark Garjainia madiba as a new species.

And in terms of size, Garjainia madiba was large enough to take on a variety of prey. Gower and colleagues estimate that the animal grew to over eight feet long, with a significant portion of that being a big, narrow-snouted skull. But what makes Garjainia madiba remarkable is not its fearsome appearance. The real story is in its bones.

Gower and colleagues examined thin sections of seven Garjainia madiba limb bones from individuals of different sizes. Inside, they found signs of rapid growth – relatively messy organization riddled with vascular canals and newly-made bone structures called primary osteons. Even in Garjainia that had periodic stopping points in their growth, likely in response to dry seasons or other times of stress, the bone in between those lines show quick growth spurts.

These starts and stops might explain why the archosauriforms, and not the surviving protomammals, came to rule the Triassic. Garjainia madiba and its relatives may have outpaced our own ancestors and cousins in terms of their life cycle, growing faster and reaching sexual maturity earlier. Simply put, the archosauriforms may have simply out-reproduced the protomammals, letting them evolve more quickly and limiting niches the protomammals could then create.

This archosauriform takeover happened quickly. Garjainia madiba lived a scant five million years after the worst mass extinction of all time – the end-Permian catastrophe that eliminated over 90% of species in the seas and over 75% of species on land. It’s a sign of a rapid burst of evolutionary novelty that paleontologists are truly just beginning to track. In the earliest days of the Triassic, life was bouncing back, with the archosauriforms leading the way.

[For more, read Mark Witton’s account of illustrating Garjainia.]

Reference: Gower, D., Hancox, P., Botha-Brink, J., Sennikov, A., Burlet, R. 2014. A new species of Garjainia Ochev, 1958 (Diapsida: Archosauriformes: Erythrosuchidae) from the Early Triassic of South Africa. PLoS One. 9, 11: e111154. doi: 10.1371/journal.pone.0111154

Ancient mammals discovery in China


This video is called Ancient Mammals. Mammal evolution from the Triassic to now.

From Science News:

Fossils push back origins of modern mammals

Common ancestor evolved over 200 million years ago

by Meghan Rosen

2:39pm, September 10, 2014

Modern mammals’ ancestors may have emerged millions of years earlier than scientists suspected — around the time the first dinosaurs roamed the Earth.

The fossilized remains of six little tree-dwelling animals push the lineage of today’s mammals back to the Late Triassic, more than 200 million years ago, researchers report September 10 in Nature.

“That’s really, really old,” says paleontologist Robert Asher of the University of Cambridge, who was not involved with the work. Scientists had thought that the common ancestor of those animals originated sometime in the Jurassic, he says. “This is very exciting stuff.”

Xianshou songae is the name of the newly discovered dinosaur age mammal.