Ancient Triassic reptile was not aquatic


LAND LIVING Eusaurosphargis dalsassoi, an ancient lizardlike critter (illustrated), wouldn’t swim well, scientists now say, arguing the creature’s style of motion and protective coverings were more suited to land. T. Scheyer/Palaeontological Institute and Museum/University of Zurich, Switzerland

By Ashley Yeager, 7:00am, August 9, 2017:

Fossil find suggests this ancient reptile lurked on land, not in the water

Exquisitely preserved specimen may overturn ideas about spiny creature’s home

A round belly, stubby feet and a tapering tail made one armored reptile a lousy swimmer. Despite earlier reports, Eusaurosphargis dalsassoi might not have swum at all, scientists now say.

E. dalsassoi was first identified in 2003. Fossils were found near Monte San Giorgio at the Swiss-Italian border alongside the remains of marine reptiles and fish that lived roughly 240 million years ago. That association led scientists to conclude the creature was aquatic. But a complete skeleton of E. dalsassoi unearthed in 2002 in the Swiss Alps and recently assembled contradicts that idea.

At just under 20 centimeters long, the fossil, probably of a youngster, shows that E. dalsassoi widened at the stomach and slithered forward with stiff elbow and knee joints and spadelike claws. That’s not a swimmer’s build, paleontologist Torsten Scheyer of the University of Zurich and colleagues report June 30 in Scientific Reports.

Armed with rows of small spikes along its back and spear-shaped plates framing its head, sides and tail, the animal resembled today’s girdled lizards. The researchers speculate that this particular E. dalsassoi died on a beach and then got washed into the ocean.

Big Triassic fossil fish discovered in Nevada, USA


Possible look of the newly discovered predatory fish species Birgeria americana with the fossil of the skull shown at bottom right. Artwork: Nadine Bösch

From the University of Zurich in Switzerland:

Large-mouthed fish was top predator after mass extinction

July 26, 2017

Summary: The food chains recovered more rapidly than previously assumed after Earth’s most devastating mass extinction event about 252 million years ago as demonstrated by the fossilized skull of a large predatory fish called Birgeria americana discovered by paleontologists from the University of Zurich in the desert of Nevada.

The most catastrophic mass extinction on Earth took place about 252 million years ago — at the boundary between the Permian and Triassic geological periods. Up to 90 percent of the marine species of that time were annihilated. Worldwide biodiversity then recovered in several phases throughout a period of about five million years. Until now, paleontologists have assumed that the first predators at the top of the food chain did not appear until the Middle Triassic epoch about 247 to 235 million years ago.

Unexpected find of a large predatory fish

Swiss and U.S. American researchers led by the Paleontological Institute and Museum of the University of Zurich have discovered the fossil remains of one of the earliest large-sized predatory fishes of the Triassic period: an approximately 1.8-meter-long primitive bony fish with long jaws and sharp teeth. This fish belongs to a previously unknown species called Birgeria americana. This predator occupied the sea that once covered present-day Nevada and the surrounding states already one million years after the mass extinction.

Triassic “Jaws

In the United States, almost no vertebrate fossils from the Early Triassic epoch (252 to 247 million years ago) have been scientifically described until now. “The surprising find from Elko County in northeastern Nevada is one of the most completely preserved vertebrate remains from this time period ever discovered in the United States,” emphasizes Carlo Romano, lead author of the study. The fossil in question is a 26-centimeter-long partial skull of a fierce predator, as evidenced by three parallel rows of sharp teeth up to 2 centimeters long along the jaw margins, as well as several smaller teeth inside the mouth.

Birgeria hunted similarly to the extant great white shark: the prey fish were pursued and bitten, then swallowed whole. Species of Birgeria existed worldwide. The most recent discovery is the earliest example of a large-sized Birgeria species, about one and a half times longer than geologically older relatives.

Predators appeared earlier than assumed

According to earlier studies, marine food chains were shortened after the mass extinction event and recovered only slowly and stepwise. In addition, researchers assumed that the ancient equatorial regions were too hot for vertebrates to live during the Early Triassic. Finds such as the newly discovered Birgeria species and the fossils of other vertebrates now show that so-called apex predators (animals at the very top of the food chain) already lived early after the mass extinction. The existence of bony fish close to the equator — where Nevada was located during the Early Triassic — indicates that the temperature of the sea was a maximum of 36°C. The eggs of today’s bony fish can no longer develop normally at constant temperatures above 36°C.

“The vertebrates from Nevada show that previous interpretations of past biotic crises and associated global changes were too simplistic,” Carlo Romano says. Despite the severity of the extinctions of that time and intense climatic changes, the food webs were able to redevelop faster than previously assumed.

Swiss Triassic reptile, new study


Eusaurosphargis dalsassoi, new specimen PIMUZ A/III 4380. Credit: Beat Scheffold; Palaeontological Institute and Museum, University of Zurich, Switzerland

From the University of Zurich in Switzerland:

Ancient Swiss reptile shows its bizarre scale armor for the first time

June 30, 2017

Grisons, 241 million years ago — Instead of amidst high mountains, a small reptile suns itself on an island beach in a warm shallow sea, where many fish and marine reptiles frolic. This is the story told by an excellently preserved new discovery of the reptile Eusaurosphargis dalsassoi studied by paleontologists from the University of Zurich.

About 20 centimeters in length, the Swiss reptile was small and juvenile, but its skin was already strongly armored with variously formed smooth, jagged or even thorny osteoderms. Its skeleton indicates a life on land, even though the animal was found together with fish and marine reptiles in the 241 million year old calcareous deposits of the Prosanto Formation near Ducanfurgga at an altitude of 2,740 meters south of Davos in the canton Grisons, Switzerland. The Swiss-British team of researchers led by Torsten Scheyer, paleontologist at the University of Zurich, and James Neenan from the Oxford University Museum of Natural History therefore assumes that it was washed off a nearby island into the sea basin and became embedded in the finely layered marine sediments after death.

Skeleton and appearance reconstructed

14 years ago, the species Eusaurosphargis dalsassoi was described using a partially preserved, completely disarticulated sample from the vicinity of the Swiss-Italian UNESCO World Heritage Site Monte San Giorgio. The new find from the Grisons Mountains, on the other hand, is very well-preserved, allowing researchers to reconstruct the skeleton and outward appearance of the animal for the first time.

In the process, they discovered something astonishing: Externally, Eusaurosphargis dalsassoi looks very similar to girdled lizards (Cordylidae), a group of small, scaled reptiles (Lepidosauria) that usually live in the dry regions of southern Africa. Some of the more strongly armored girdled lizard species could have served as the basis of mythical dragon legends due to their appearance. “This is a case of convergent development as the extinct species is not closely related to today’s African lizards”, Scheyer explains.

Related to Helveticosaurus

An exact examination of the phylogenetic relationships rather confirms that its closest relatives are marine reptiles such as ichthyosaurs (Ichthyosauria or “fish lizards”), sauropterygians (Sauropterygia “lizard flippers”) or even Helveticosaurus, a marine reptile that is unique to Switzerland, all of which have been found at Monte San Giorgio. The skeleton of Eusaurosphargis, however, shows neither a streamlined body structure, nor arms and legs that have transformed into flippers, as well as no tail fin, which would indicate a life at sea.

Discovery initially identified as fish remains

The astonishing fossil was originally discovered 15 years ago by amateur paleontologist and fossil preparator Christian Obrist during systematic fossil excavations of the University of Zurich under the leadership of Heinz Furrer, which were sponsored by the Natural History Museum of the Grisons in Chur and by the Grisons canton. It took more than a decade for the scientific value of the exceptional discovery to gradually be recognized as a result of elaborate preparation. The fossil was namely initially identified as simple fish remains. “The excavations at Ducanfurgga are still in progress today and will hopefully reveal other spectacular discoveries in the future,” Furrer says.

See also here.

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.”

Dinosaur age caecilian amphibian ancestor discovered?


This video says about itself:

19 June 2017

A new analysis of a pair of tiny fossils found in the 1990s has helped scientists to uncover the backstory of the most mysterious amphibian alive. Researchers used 3D X-rays to map out the remains of a now-extinct species that walked the Earth [220] million years ago. They found that the species is a long-missing amphibious link that expands the known history of frogs, toads and salamanders by at least 15 million years. Chinlestegophis jenkinsi (artist’s impression) was a tiny subterranean carnivore.

From Science News:

New fossils shake up history of amphibians with no legs

Tiny skulls and other bits hint at unexpected backstory for today’s snake-shaped caecilians

by Susan Milius

3:30pm, June 19, 2017

Newly named fossils suggest that a weird and varied chapter in amphibian deep history isn’t totally over.

Small fossils about 220 million years old found along steep red slopes in Colorado represent a near-relative of modern animals called caecilians, says vertebrate paleontologist Adam Huttenlocker of the University of Southern California in Los Angeles.

Caecilians today have long wormy bodies with either shrunken legs or none at all. Yet the nearly 200 modern species of these toothy, burrow-dwelling tropical oddballs are genuine amphibians. The fossil creatures, newly named Chinlestegophis jenkinsi, still had legs but could be the oldest known near-relatives of caecilians, Huttenlocker and colleagues suggest.

A popular view of the amphibian family tree has put caecilians on their own long, peculiar branch beside the ancient frogs and salamanders. But a close look at the new fossils suggests a much earlier split from ancestral frogs and salamanders, the researchers propose June 19 in Proceedings of the National Academy of Sciences. The move puts the caecilians into “a strange but incredibly diverse” group, the stereospondyls, Huttenlocker says. These species included elongated, short-legged beasts with heads shaped like toilet lids.

Among the many stereospondyls, Huttenlocker speculates that caecilians came from “an aberrant branch of miniaturized forms that went subterranean.” And today’s legless burrowers could be this once-flourishing group’s sole survivors.

Brazilian mammal-like reptile fossils, new study


This video from the USA says about itself:

Lecture 65: Cynodonts: Between Reptile and Mammal

8 November 2016

In this video we will list the major innovations in the cynodonts leading toward the origin of modern mammals.

From ScienceDaily:

Brazilian carnivorous mammal-like reptile fossil may be new Aleodon species

Brazilian specimens previously thought to be Chiniquodon may be first non-African Aleodon

June 14, 2017

Summary: Some Late Triassic Brazilian fossils of mammal-like reptiles, previously identified as Chiniquodon, may in fact be the first Aleodon specimens found outside Africa.

Some Late Triassic Brazilian fossils of mammal-like reptiles, previously identified as Chiniquodon, may in fact be the first Aleodon specimens found outside Africa, according to a study published June 14, 2017 in the open-access journal PLOS ONE by Agustín Martinelli from the Universidade Federal of Rio Grande do Sul, Brazil, and colleagues.

Aleodon is a genus of probainognathian cynodont, a taxon which evolved in the Triassic period, co-existed with dinosaur precursors and other archosaurs and eventually gave rise to mammals. The Aleodon genus was first described using fossils from Tanzania and Namibia, but it was not clear if it belonged within the family of carnivorous mammal-like reptiles known as Chiniquodontids, which includes the morphologically similar Chiniquodon.

The authors of the present study examined the skulls, jaws and teeth of Middle-Late Triassic fossil specimens from the Dinodontosaurus Assemblage Zone in Rio Grande do Sul, Brazil, most of which were previously thought to be Chiniquodontids, and compared them to a known African Aleodon species, A. brachyrhamphus.

The researchers used tooth morphology to identify one of the specimens as a new Aleodon species, which they named A. cromptoni after Dr Alfred “Fuzz” Crompton, who described the Aleodon genus. They also identified as Aleodon seven Brazilian specimens, previously thought to be chiniquodontids or traversodontids, and possibly one Namibian specimen, noting that this may call the reliability of Chiniquodon identification into question. Phylogenetic analysis indicated that Aleodon cromptoni may be, as suspected, a species in the Chiniquodonidae family.

Whilst the analysis was limited by the partial nature of some of the specimens, the authors note that the identification of these Late Triassic Aleodon specimens in Brazil strengthens the correlation between probainognathians from this epoch in South America and in Africa.

‘Paleontological’ football club in Winterswijk


This 18 August 2015 video is about a match in the Dutch football cup competition between two clubs from Winterswijk: FC Winterswijk and FC Trias.

FC Trias got its name because it is a fusion of three earlier clubs.

However, the club grounds are also not far from the Winterswijk quarry. Where muschelkalk stone from the Triassic, over 200 million years ago, is mined. The Triassic got its name from its three distinct rock layers. The Dutch word for Triassic is Trias. In the Winterswijk quarry, recently, a Triassic beetle was discovered; and,earlier, Triassic marine reptiles.