Tag Archives: triassic

#FossilFriday: This 250-million-year-old animal could enter hibernation-like states

Illustration of Lystrosaurus in a state of torpor. Credit: Crystal Shin.

Many creatures on Earth today hibernate, essentially entering a state of low metabolism that allows them to go through months at a time without food. According to researchers, this adaptation may be at least 250 million years old, judging from the fossils of a recently described creature that could enter a hibernation-like state.

The fossils of the mammal-like creature, which belongs to the genus Lystrosaurus, were retrieved from Antarctica. Although during Lustrosaurus’ days Antarctica may have been much more welcoming, it would have still experienced extended periods without sunlight each winter.

“Animals that live at or near the poles have always had to cope with the more extreme environments present there,” said lead author Megan Whitney, a postdoctoral researcher at Harvard University who conducted this study as a University of Washington doctoral student in biology. “These preliminary findings indicate that entering into a hibernation-like state is not a relatively new type of adaptation. It is an ancient one.”

The stout, four-legged forager was roughly pig-sized, although some could grow up to 8 feet long (2.5 meters). Lystrosaurus, which has been found in India, China, Russia, Africa, and now Antarctica, had no teeth at all. Instead, the stubby vertebrate had a pair of tusks in the upper jaw, which likely served to penetrate ground vegetation and dig out roots and tubers.

Like elephants, these tusks grew continuously throughout Lystrosaurus‘s life. In their new study, Whitney and colleagues used cross-sections of fossilized tusks to infer valuable information about the metabolism, growth, and stresses of during these creatures’ lifetimes. They did so for many specimens, comparing cross-sections of tusks from six Antarctic Lystrosaurus to cross-sections of four Lystrosaurus from South Africa.

During Lystrosaurus‘ heyday in the Triassic, South Africa and Antarctica were joined together in a supercontinent called Pangea. Back then, Antarctica was about 72 degrees south latitude (still well within the Antarctic circle) while South Africa was displaced by more than 550 miles north compared to its position today, sitting at a warm 58-61 degrees south latitude.

This thin-section of the fossilized tusk from an Antarctic Lystrosaurus shows layers of dentine deposited in rings of growth. Credit: Megan Whitney/Christian Sidor

Similar to how a tree’s rings can tell how many years it was alive for, or when it suffered drought, layers of dentine were also deposited in concentric circles in the fossilized tusks. Curiously, Antarctic tusks had thicker, more closely spaced dentin rings, indicating periods of less deposition. For the researchers, this suggests periods of prolonged stress that resemble the effects of hibernation.

“The closest analog we can find to the ‘stress marks’ that we observed in Antarctic Lystrosaurus tusks are stress marks in teeth associated with hibernation in certain modern animals,” said Whitney.

That’s not to say that the researchers can definitely conclude that Lystrosaurus could hibernate, which is essentially a resting state of deep sleep, during which the body’s metabolic rate and temperature drop considerably. For instance, during hibernation, the gopher’s body temperature will drop from its normal 37 degrees Celsius to almost 0 degrees Celsius. The heartbeat also becomes slow and irregular, alongside a slowing breathing rate.

A map of Pangea during the Early Triassic, showing the locations of the Antarctic (blue) and South African (orange) Lystrosaurus populations compared in this study. Credit: Megan Whitney/Christian Sidor.

The same stress may have been caused by another hibernation-like form of torpor, which involves a more short-term reduction in metabolism, the researchers wrote in the journal Communications Biology.

In any event, Lystrosaurus must have benefited greatly from hibernation-like states. Although Antarctica was much warmer than it is today and might have even been forested during the Triassic, it would have still experienced extreme annual variations of daylights, with the sun absent for months at a time during winter. Torpor may have helped creatures such as Lystrosaurus cope with the dire strains of pitch-black winter.

“To see the specific signs of stress and strain brought on by hibernation, you need to look at something that can fossilize and was growing continuously during the animal’s life,” said co-author Christian Sidor, a University of Washington professor of biology and curator of vertebrate paleontology at the Burke Museum. “Many animals don’t have that, but luckily Lystrosaurus did.”

If the findings are confirmed, this means  Lystrosaurus is the earliest example of a hibernating vertebrate that we know of. It would also highlight the fact that many different features of modern animals likely existed hundreds of millions of years ago, long before any humans were around to study them.

“Cold-blooded animals often shut down their metabolism entirely during a tough season, but many endothermic or ‘warm-blooded’ animals that hibernate frequently reactivate their metabolism during the hibernation period,” said Whitney. “What we observed in the Antarctic Lystrosaurus tusks fits a pattern of small metabolic ‘reactivation events’ during a period of stress, which is most similar to what we see in warm-blooded hibernators today.”

Pappochelys rosinae lived during the Triassic Period, about 240 million years ago. Credit: Wikimedia Commons.

Rare bone cancer found in 240-million-year-old turtle

Pappochelys rosinae lived during the Triassic Period, about 240 million years ago. Credit: Wikimedia Commons.

Pappochelys rosinae lived during the Triassic Period, about 240 million years ago. Credit: Wikimedia Commons.

Cancer is not a recent phenomenon but rather a pervasive disease that has been plaguing creatures probably since the first multicellular organisms evolved billions of years ago. That’s an assumption, though, because no one truly knows when cancer first appeared because it’s very challenging to spot in fossils. Typically, cancer gets preserved in soft tissue and very rarely in fossilized remains. This is why this latest study is so exciting — it details the case of bone cancer found in a 240-million-year-old shell-less turtle. According to researchers, this may be the oldest case of bone cancer found in an amniote (reptile, bird, or mammal).

In order to detect cancer, the researchers led by Bruce Rothschild, a research associate at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, used microscopy and computerized tomography to peer inside the ancient turtle’s left femur. The Triassic fossil was discovered in Germany about six years ago and belongs to Pappochelys rosinae. The reptile was only 20 centimeters long (8 inches) and had broad ribs. It didn’t have any shell — the signature feature which modern turtles are known for evolved 30 million years later. The origin of the turtle’s shell is a fascinating and controversial subject among biologists, and a whole story in itself.

The scans showed a peculiar mass in a layer of the bone called the periosteum. The researchers ruled out an infection and concluded that the lesion was malignant periosteal osteosarcoma, a type of bone cancer. Curiously, the cancer is almost identical to the osteosarcomas afflicting humans today. The oldest cancer in a human ancestor was also a bone cancer, a foot bone belonging to a relative who died in Swartkrans Cave, South Africa, between 1.6 and 1.8 million years ago.

It’s impossible to know for sure whether this cancer was ultimately responsible for the turtle’s demise but we know from cases in humans that the disease often spreads to the lungs. If that was the case here as well, the turtle would have become weak and less able to escape or feed, making it vulnerable to predators and other diseases.

The cancer can be seen in the upper half of the femur bone. Credit: Haridy et al, JAMA.

The findings published in JAMA Oncology are important for cancer research, suggesting that ancient and modern cancer share deep evolutionary roots. The fact that researchers have not only been able to identify cancer, but also diagnose a rare subtype suggests that the disease hasn’t changed very much in millions of years.

New Antarctic Dinosaurs on Display at Field Museum

The world-renowned Field Museum of Chicago, Illinois has a new prehistoric creature display gracing their halls and galleries. The place has been decked out with fossil reconstructions and artistic representations of a variety of prehistoric animals. Most famous, of course, are those of the dinosaurs — and one of the newest additions is Antarctic Dinosaurs.

Around 195 to 235 million years ago (an era which encompasses the Triassic period as well as a small portion of the Jurassic period), Antarctica was quite different from its modern-day appearance. The Antarctic would have been closer to the equator, making for a lush habitat filled with “rhinoceros-sized dinosaurs and crocodile-sized amphibians,” says Kate Golembiewski, the public relations/science communications manager at the museum.

The exhibition includes hands-on interactive sections which can bring out the child in everyone. A significant portion of the exhibit is dedicated to the history of Antarctica in respect to man’s journeying there and learning how to survive the harsh, frigid conditions. Altogether, there are four dinosaur species appearing in the exhibit.

Glacialisaurus, a herbivorous dinosaur, is included as is a group of small sauropodomorphs which were ancestors of the massive long-necked sauropods. The titanosaur Maximo, which is also on display at the Field, is an example of the towering sauropods which are thought to have evolved along this lineage.

A life-like replica of the sauropodomorphs. Source: Of Intellect and Interest. Photo by John Tuttle.

Two of the dinosaur species on display were classified as sauropodomorphs. As yet, these new species have not been assigned personal scientific descriptions. The pride and joy of this entire display, however, is likely the Cryolophosaurus, a formidable predator of the area and era.

This carnivorous brute was a fierce hunter. The specimen present in Antarctic Dinosaurs measures 25 feet, which is not something you’d want to meet in a dark alley. Aside from the dinosaurs, there are other wondrous creatures which found their place in the exhibit.

It also features specimens of lichens, large amphibians, and even the skeleton of a sizeable aquatic carnivore known as Taniwhasaurus. It was a mosasaur, a relative to the giant marine animals depicted in the Jurassic World films, and is believed to have been able to reach lengths of close to 39 feet. It would have been a dangerous foe for any smaller swimmers of the Cretaceous period.

Altogether, the exhibit has something to offer everyone of every age, from child to adult, and of every interest, from history to paleontology, and is a great way to spend an afternoon or a day off.

Fossil Friday: Helicoprion

Helicoprion bessonovi fossil, housed at The Idaho Museum of Natural History’s Earth Science collection.
Image via imnh

Helicoprion is an extinct genus of shark-like, cartilaginous fish that lived from the early Permian (~290 m.y. ago) all through to the massive Permian-Triassic extinction episode (roughly 250 m.y. ago.)

Their most distinctive characteristic, the lower jaw, baffled scientists for over a hundred years. This “tooth-whorl” structure was the only bony tissue to be found in the animal’s body, and the only part of it that fossilizes under normal conditions — so for all this time, paleontologists didn’t have enough context to describe it beyond “round…thingy. With teeth!”

In 2011 IMNH researchers performed a CT scan on an exceptionally well preserved specimen that contained the elusive jaws. The research eventually led to the first accurate reconstruction of the shark as well as placing in its proper position on the great tree of life.

The CAT scans also allowed a partial reconstruction of the rest of the animal, estimated to have been 3-4 meters (9.8 to 13.1 feet) long, but some potentially grew to almost 7.5 meters (24.6 feet) long. As their jaws aren’t resilient enough to break shells, Helicoprion most likely dined on soft prey, such as mollusks.

Dinosaurs were warm-blooded, new study finds

New controversial research concluded that dinosaurs weren’t the cold blooded lizards we tend to see them today – instead, they had much in common with mammals, and were warm blooded.

Image via Science Daily.

Dinosaurs first emerged in the Triassic, 231.4 million years ago, and were the dominant terrestrial vertebrates for 135 million years, from the beginning of the Jurassic (about 201 million years ago) until the end of the Cretaceous (66 million years ago). We tend to think of dinosaurs as giant lizards, but the truth may be more complicated (and surprising) than that.

“Upon re-analysis, it was apparent that dinosaurs weren’t just somewhat like living mammals in their physiology — they fit right within our understanding of what it means to be a ‘warm-blooded’ mammal,” author Michael D’Emic, a Stony Brook University paleontologist, said in a press release.

Dinosaur blood is a controversial issue; in 2011, CalTech researchers proposed the same thing – that dinosaurs were warm-blooded, and the study was met both praised and contradicted by other paleontologists. Now, more and more analysis seems to back that idea up. For this study, D’emic re-analyzed a huge dataset published in a previous study on growth and metabolism of hundreds of living animals, a dataset which he calls “remarkable” and “unprecedented”.

The first question mark arose from studying growth rates.

“This is problematic,” D’Emic said, “because many animals do not grow continuously throughout the year, generally slowing or pausing growth during colder, drier, or otherwise more stressful seasons. Therefore, the previous study underestimated dinosaur growth rates by failing to account for their uneven growth. Like most animals, dinosaurs slowed or paused their growth annually, as shown by rings in their bones analogous to tree rings.”

Seasonal environments and extreme circumstances could also impact growth.

Vertebrate paleontologist Michael D’Emic says were warm-blooded just like today’s mammals.

The other aspect is rather straightforward, and was discussed before: birds evolved from some dinosaurs, and birds are warm blooded, so why wouldn’t dinosaurs:

“Separating what we commonly think of as ‘dinosaurs’ from birds in a statistical analysis is generally inappropriate, because birds are dinosaurs–they’re just the dinosaurs that haven’t gone extinct,” D’emic added.

His conclusions were actually based on a previous study published in Science, which found that dinosaurs were neither warm or cold blooded, but instead occupied a middle position and were mesotherms. But the authors of the original study stand by their initial conclusions.

“We disagree with his central criticisms and we emphasize that all of our original conclusions stand,” said University of New Mexico biologist John Grady. “Comparing dinosaur growth with the observed growth rate of living vertebrates clearly shows that non-avian dinosaurs were mesotherms,” added Grady, using the term for an intermediate metabolism.

But D’Emic raised another point, that of adaptations to overheating.

“The Earth was generally warmer during the time of the dinosaurs, and so overheating could have been a problem for them. However, most large dinosaurs had some hollow, air-filled bones in their skeleton and likely had large air sacs in other parts of their bodies, just like birds today,” D’Emic said.

If he is right in his theory, then this means we have to re-evaluate what we think about ornaments that some dinosaurs had, like the spinal sails of the Stegosaurus. But either way, the idea of cold blooded dinosaurs seems less and less likely.

Another interesting aspect of this study is that it might provide new insight into the growth and development of human bones, including treating diseases such as osteoporosis.

Car-sized Salamander roamed Portugal 230 million years ago

Paleontologists have found the remains of a “super salamander” – a previously unknown car-sized species of early amphibian. The predatory salamander likely feasted on fish and even small dinosaurs.

“This new amphibian looks like something out of a bad monster movie. It was as long as a small car and had hundreds of sharp teeth in its big flat head, which kind of looks like a toilet seat when the jaws snap shut,” said Dr Steve Brusatte, of the University of Edinburgh’s School of GeoSciences, who led the study.

An artist’s impression of the giant carnivorous amphibian Metoposaurus algarvensis, discovered by researchers from the University of Edinburgh Photograph: University of Edinburgh/PA

 

Scientists now know quite a lot about these creatures – they lived together in large numbers, grew up to more than 2 meters, and lived in low-lying lakes and rivers during the Late Triassic Period, the first major stage of the Mesozoic. Researchers can say for sure that it is a new species, judging by its jaw structure and parts of the skull where the spinal cord meets the brain.

“We have a mass graveyard of these things that looks like hundreds of individuals all jumbled together,” Steve Brusatte, who led the study, told The Washington Post in a phone interview. “These things lived and died together. We have skeletons of many different individuals, adults and children … We know what it ate, how it moved and what it was like when it was alive.”

Image credits: Steve Brusatte.

The species is now called Metoposaurus algarvensis, named after the Algarve province in southern Portugal where it was discovered. The area where they found it likely contains many more still undiscovered fossils, but to date, only a fraction of them were actually excavated.

“There is a real jumble of bones in there, but it’s been challenging to remove them because they come from a bone bed that is about half a metre thick and goes into the hillside,” said Steve Brusatte, who led the study. The team have spent two field trips excavating bones from the site and hope to return to collect more of the remains.

For all its spectacular size, Metoposaurus algarvensis had puny legs, which indicates that it mostly hunted in the water, as it wasn’t specially adapted to land. It was likely quite vulnerable on land. This is the first member of the Metoposaurus group found in the Iberian peninsula (Portugal and Spain). But despite their strange looks, they were likely quite common in the area.

“It looks like an alien — it looks like it’s from another world,” Brusatte said. “But these animals weren’t rare at all.” Indeed, big amphibians dominated planet Earth until volcanic activity associated with Pangea’s break-up paved the way for the T. Rex and its dino compatriots.

Journal Reference: Stephen L. Brusatte, Richard J. Butler, Octávio Mateus & J. Sébastien Steyer. A new species of Metoposaurus from the Late Triassic of Portugal and comments on the systematics and biogeography of metoposaurid temnospondyls. DOI:10.1080/02724634.2014.912988

Artist impression of the "Carolina Butcher," Carnufex carolinensis. Credit: JORGE GONZALES

Croc ancestor was the top two-legged predator on Earth, long before T. Rex and other dinosaurs

Long before T-rex claimed the top dog spot among terrestrial predators, a vicious crocodile ancestor that walked on its hind legs was at the top of the food chain during the Triassic. The fossils of the Carnufex carolinensis, also known as the the “Carolina Butcher,” were discovered decades ago  in the Pekin Formation, a geological formation in North Carolina’s Chatham County. It was only recently that researchers reanalyzed the fossils and concluded they were dealing with an all new predator that roamed the Earth several million years before dinosaurs were even around.

Artist impression of the  "Carolina Butcher," Carnufex carolinensis. Credit: JORGE GONZALES

Artist impression of the “Carolina Butcher,” Carnufex carolinensis. Credit: JORGE GONZALES

Lindsay Zanno, an assistant professor at North Carolina State University and the lead author of a paper describing the research, was among those who first analyzed the ancient fossils. She and her team dated the ancient croc as being 231 million years old. Using a high-resolution surface scanner, the team mapped the croc’s skull and created a 3-D model which revealed it was littered with dozens of blade-like teeth. In all likelihood, it used them to slice meat from the bones of the animals it killed or scavenged.

The model also showed that the Carolina Butcher stood at least 9 feet tall and most likely walked on two legs, judging from the forelimb to skull ratio (very similar to T. Rex). Sometime in the Late Triassic, however, the beasts went extinct following a massive wipe-out. In the end, its place was taken by large dinosaurs. But the smaller ancestors of crocodiles made it through the extinction, and eventually evolved in today’s crocs and alligators.

Reconstructed skull of Carnufex carolinensis

Reconstructed skull of Carnufex carolinensis.

The discovery is important since it fills an evolutionary gap. Even so, there are still unknowns further up the ladder, like who’s the common ancestor of the dinosaur line and the crocodile line?

A paper was published in the journal Scientific Reports.

How some dinosaurs got enormously long necks

The longest creatures to ever walk the Earth were the long-necked, long-tailed dinosaurs known as the sauropods. But why did these huge vegetarians grow such huge necks, reaching up to 15 meters? That’s six times longer than that of the current world-record holder, the giraffe.

 

“They were really stupidly, sauropodabsurdly oversized,” said researcher Michael Taylor, a vertebrate paleontologist at the University of Bristol in England. “In our feeble, modern world, we’re used to thinking of elephants as big, but sauropods reached 10 times the size elephants do. They were the size of walking whales.”

The secret, according to him and his team was mostly hollow neck bones. To find out just how sauropod necks could get so long, scientists analyzed other long-necked creatures and compared sauropod anatomy to that of their closest living relatives – birds and crocodiles.

“Extinct animals — and living animals, too, for that matter — are much more amazing than we realize,” Taylor explained. “Time and again, people have proposed limits to possible animal sizes, like the five-meter (16-foot) wingspan that was supposed to be the limit for flying animals. And time and again, they’ve been blown away. We now know of flying pterosaurs with 10-meter (33-foot) wingspans. And these extremes are achieved by a startling array of anatomical innovations.”

Unsurprisingly, Taylor and his colleagues found several adaptations that supported long necks. The most notable feature was that air often made up 60 percent of these animals’ necks, with some of them as light as birds bones, making it easier to support the giant lengths. The muscles, ligaments and tendons were also positioned in a way that helped maximize leverage, making neck movements more efficient. Furthermore, their giant torsos and four-legged stances helped provide a stable platform for their necks; in contrast, giraffes have really small torsos compared to the rest of their bodies. The number of vertebrae was also important: while most mammals (with the exception of the sloths and manatees) have maximum 7 vertebrae in their necks, sauropods had 19 (which is still not that much comparing the sizes).

sauropod2

Another interesting fact which enabled them to grow such big necks was their small head size; sauropods didn’t even had cheeks to store food for chewing. As a matter of fact, they didn’t even chew food, they just swallowed it and let the gut digest it.

“Sauropod heads are essentially all mouth. The jaw joint is at the very back of the skull, and they didn’t have cheeks, so they came pretty close to having Pac Man-Cookie Monster flip-top heads,” researcher Mathew Wedel at the Western University of Health Sciences in Pomona, Calif., explained. “It’s natural to wonder if the lack of chewing didn’t, well, come back to bite them, in terms of digestive efficiency. But some recent work on digestion in large animals has shown that after about 3 days, animals have gotten all the nutrition they can from their food, regardless of particle size. And sauropods were so big that the food would have spent that long going through them anyway,” Wedel said. “They could stop chewing entirely, with no loss of digestive efficiency.”

But the question remains: why did they evolve like this? Well, there’s no clear answer so far, but there are three theories: either to reach leaves from high trees, either to graze large portions of vegetations by sweeping, with lower effort or… because it made them more sexually attractive. Taylor’s research however, didn’t provide an answer for this question.

Bus sized Triassic marine monster sheds light on ecosystems

A new species of “sea monster” was unearther in Nevada – a predator so fierce that it often hunted prey as big or bigger than itself.

ichthyosaurus-sea-monster-secrets-revealed_62934_600x450

Thalattoarchon saurophagis translates into “lizard-eating sovereign of the sea” – and boy is that a good name. It measured well over 8 meters and lived some 244 million years ago, during the Triassic, before the Jurassic period. The creature was an early ichtyosaur, giant marine reptiles that resembled dolphins but were the dominant marine predators for tens of millions of years.

Paleontologists from the Berlin’s Museum of Natural History said the fossil is unusually well preserved, maintaining its skull, fins, and entire vertebral column.

“It is pretty amazing, particularly for an animal this size,” said Fröbisch, who is also a National Geographic explorer.

ichtyosaur fossil

Ichtyosaur fossil

If Thalattoarchon would have any equivalents today, those would be sharks and killer whales (oracas). But what’s truly interesting about the fossil is that it shows how species and even ecosystems could bounce back from the most catastrophic event.

Nature’s struggles

“This animal occurs only eight million years after the biggest mass extinction event in Earth’s history, the Permian extinction, which literally wiped out up to 95 percent of all the species in the ocean,” Fröbisch explained. “The ocean was a pretty empty place afterward.”

permian_extinct5_hThe Permian extinction was indeed the most tragic event in our planet’s history; it occured 252.28 million years ago and its exact cause (or causes) are still unknown. It was a key moment for all life on Earth, much more difficult than the event that wiped out the dinosaurs 65 million years ago. But fossil records showed that life quickly bounced back after this event, despite all odds.

Where does Thalattoarchon fit in ? Well, when ecosystems bounce back, they bounce from the bottom up. If a top predator like itself appears, that means there’s a whole lot of food for it available, which means that the ecosystem has pretty much recovered; to put it another way, top predators are the last ones to reemerge.

“So with the appearance of Thalattoarchon we know it was complete and that it had the same structure as modern ecosystems, the same structure we’ve seen in place, with different players, ever since.”

Despite thriving for over 160 million years as the top predator, Thalattoarchon and his fellow ichtyosaurs vanished without a trail, without leaving any indication as to what led to their demise, and without leaving any descendants.

“Toward the end of the Cretaceous, they declined more and more, and their diversity also declined—and then they finally disappeared,” Fröbisch said.

It’s actually possible that at one point, they became too good for their own sake – virtually eliminating all the food sources available.

Via National Geographic