. Scientific Frontline: Paleontology
Showing posts with label Paleontology. Show all posts
Showing posts with label Paleontology. Show all posts

Wednesday, January 4, 2023

‘Veggie’ dinosaurs differed in how they ate their food

Some of the finite element models compared bite performance across the five ornithischian dinosaurs in the study, with different models showing different bite points. Cooler colors (blue) represent areas of low stress while hot colors (red and pink) indicate areas that are highly stressed.
Illustration Credit: David Button

Although most early dinosaurs were vegetarian, there were a surprising number of differences in the way that these animals tackled eating a plant-based diet, according to a new study by scientists from the Natural History Museum and the Universities of Bristol and Birmingham.

Scientists used CT scans of dinosaur skulls to track the evolution of early dinosaur herbivores - reconstructing jaw muscles and measuring the animals’ bite force to understand how dinosaur feeding evolved.

Five skulls from the plant-eating group Ornithischia provided the key to unlocking their feeding habits: Heterodontosaurus, Lesothosaurus, Scelidosaurus, Hypsilophodon and Psittacosaurus - earliest representatives of what would become the major herbivore dinosaur groups.

Later ornithischian dinosaurs, like Triceratops and Stegosaurus, show a wide range of adaptations to eating plants yet their early relatives have not been examined properly, until now.

Monday, December 19, 2022

Fossil CSI: Mysterious site was ancient birthing grounds

Adult and young of the ichthyosaur species Shonisaurus popularis chase ammonoid prey 230 million years ago, in what is now Berlin-Ichthyosaur State Park, Nevada, U.S.A.
Illustration Credit: Gabriel Ugueto 

Today’s marine giants—such as blue and humpback whales—routinely make massive migrations across the ocean to breed and give birth in waters where predators are scarce, with many congregating year after year along the same stretches of coastline. Now, new research from a team of scientists—including researchers with the University of Utah (Natural History Museum of Utah and Department of Geology & Geophysics), Smithsonian Institution, Vanderbilt University, University of Nevada, Reno, University of Edinburgh, University of Texas at Austin, Vrije Universiteit Brussels, and University of Oxford—suggests that nearly 200 million years before giant whales evolved, school bus-sized marine reptiles called ichthyosaurs may have been making similar migrations to breed and give birth together in relative safety.

The findings, published today in the journal Current Biology, examine a rich fossil bed in the renowned Berlin-Ichthyosaur State Park (BISP) in Nevada’s Humboldt-Toiyabe National Forest, where many 50-foot-long ichthyosaurs (Shonisaurus popularis) lay petrified in stone. Co-authored by Randall Irmis, NHMU chief curator and curator of paleontology, and associate professor, the study offers a plausible explanation as to how at least 37 of these marine reptiles came to meet their ends in the same locality—a question that has vexed paleontologists for more than half a century.

Friday, December 16, 2022

Scientists discover what was on the menu of the first dinosaurs

Early dinosaurs and their diets. Lesothosaurus is an omnivore, Buriolestes is a carnivore and Thecodontosaurus is an herbivore
Illustration Credit: Gabriel Ugueto

The earliest dinosaurs included carnivorous, omnivorous and herbivorous species, according to a team of University of Bristol paleobiologists.

By looking at the tooth shapes of the earliest dinosaurs and simulating their tooth function with computational modelling, experts were able to compare them to living reptiles and their diets. Their findings, published today in Science Advances, show that many groups of plant-eating dinosaurs were ancestrally omnivorous and that the ancestors of our famous long-necked herbivores, such as Diplodocus, ate meat. This ability to diversify their diets early in their evolution likely explains their evolutionary and ecological success.

The earliest dinosaurs are enigmatic: they were much smaller than their later relatives and for most of the Triassic they were in the shadow of crocodile-like reptiles. It is unknown how diverse they were in terms of diets and ecology, but scientists know something must have happened in the Triassic that allowed dinosaurs to endure the Triassic–Jurassic mass extinction and adapt in its aftermath, becoming the dominant group for the rest of the Mesozoic.

Tuesday, December 13, 2022

Fossil site reveals giant arthropods dominated the seas 470 million years ago

Fossils from the Fezouata Shale. From left to right, a non-mineralized arthropod (Marrellomorpha), a palaeoscolecid worm and a trilobites.
Image Credit Emmanuel Martin.

Discoveries at a major new fossil site in Morocco suggest giant arthropods – relatives of modern creatures including shrimps, insects and spiders – dominated the seas 470 million years ago.

Early evidence from the site at Taichoute, once undersea but now a desert, records numerous large “free-swimming” arthropods.

More research is needed to analyze these fragments, but based on previously described specimens, the giant arthropods could be up to 2m long.

An international research team says the site and its fossil record are very different from other previously described and studied Fezouata Shale sites from 80km away.

They say Taichoute (considered part of the wider “Fezouata Biota”) opens new avenues for paleontological and ecological research.

Monday, December 12, 2022

True giant wombat gives Diprotodon podium a wobble

Ramsayia reconstruction (r) next to a modern wombat.
Illustration Credit: Eleanor Pease, CC BY-NC

If you thought Australia was home to only one ancient ‘giant wombat’, think again.

While the Diprotodon – the extinct megafauna species that is distantly related to wombats but was the size of a small car – is commonly (but incorrectly) thought of as Australia’s ‘giant wombat’, researchers from Griffith University have shed light on a large species that does belong in the modern-day wombat family.

The complete skull of this true fossil giant wombat, found in a Rockhampton cave in Queensland and estimated to be around 80,000 years old, has been described for the first time by a team led by Associate Professor Julien Louys from Griffith’s Australian Research Centre for Human Evolution.

Friday, December 9, 2022

Smilodon's saber teeth

Life-size reconstruction of three different species studied with their stress thermal maps at the three different angles for a right lower canine bite. The colder colors on the thermal maps of saber-toothed species indicate lower stress and higher force, especially when biting at larger angles.
Illustration Credit: Massimo Molinero

A team of researchers led by Narimane Chatar, doctoral student at EDDyLab at the University of Liège, tested the bite effectiveness of the Smilodon, an extinct species of carnivore close to current felines. Thanks to high precision 3D scans and simulation methods, the team has just revealed how these animals managed to bite despite the impressive length of their teeth. This study is the subject of a publication in the journal Proceedings of the Royal Society B

ancient carnivorous mammals have developed a wide range of skulls and teeth throughout their evolution. However, few of these developments have yet equaled those of the felidated saber-toothed emblematic Smilodon. Other groups of mammals, such as the now extinct nimravids, have also evolved into a similar morphology, with species with saber teeth but also much shorter canines, similar to those of lions, tigers, caracals, domestic cats, etc. that we know today. This phenomenon of the appearance of similar morphologies in different groups of organisms is known as convergent evolution; felines and nimravids being an astonishing example of convergence. As there are no modern animal equivalents with such saber-shaped teeth, the hunting method. Smilodon and other similar species remained obscure and the subject of heated debate. It was initially suggested that all saber-toothed species hunted in the same way, regardless of the length of their canines, a hypothesis which is today controversial. From then on, the question remained suspended ... How did this variety of "saber-toothed cats" hunt?

Very fast, but not a supersonic

The computer model of the dinosaur tail used and a diplodocide
Image Credit: Simone Conti / Zachi Evenor

An international research team with the participation of the Department of Biology at the University of Hamburg has analyzed the mobility of dinosaur tails using computer models and methods from engineering. According to a study published in Scientific Reports, the researchers found that these tails could be moved more than 100 kilometers per hour. Unlike previously assumed, however, they did not reach supersonic speed.

Diplodocids were large herbivorous dinosaurs with long necks and long tails. In a previous study, it was believed that a hypothetical structure at the end of a diplodocid's tail, similar to the end of a whip, could move faster than the speed of sound (340 meters per second) and produce a supersonic bang.

To test this hypothesis, the international research team simulated the movements of the tail of diplodocids using a model based on five fossil diplodocid skeletons. The virtual tail model is over 12 meters long, would weigh 1,446 kilograms in real terms and consists of 82 cylinders, which are supposed to represent vertebrae and are attached to an immovable, virtual basin.

“Research was quite a challenge, because we had to tackle the problem with two methods, that are normally used in aerospace technology: multi-body simulation and the estimation of the resilience of the materials”, reports the first author of the study, Simone Conti from the Universidade NOVA de Lisboa and the Politecnico di Milano.

Thursday, December 1, 2022

Mammoth problem with extinction timeline

Cameron Schwalbach, paleontology collections manager for the Cincinnati Museum Center’s Geier Collections and Research Center, and UC assistant professor Joshua Miller examine a mammoth skull. Photo Credit: Andrew Higley/UC Marketing + Brand

Exactly when mammoths went extinct has fascinated paleontologists for generations, perhaps because their decline coincided with the arrival of people to North and South America.

So, it’s only natural to wonder if humans more than contributed to the extinction of these enormous beasts of the ice age more than 10,000 years ago.

A University of Cincinnati paleontologist refutes the latest timeline published in 2021 in the journal Nature that suggested mammoths met their end much more recently than we believed. An international team of researchers examined environmental DNA of mammoth remains and more than 1,500 arctic plants to conclude that a wetter climate quickly changed the landscape from tundra grassland steppe to forested wetlands that could not support many of these big grazing animals, driving mammoths to extinction as recently as 3,900 years ago.

But in a rebuttal paper to be published Dec. 1 in Journal Nature, UC College of Arts and Sciences assistant professor Joshua Miller and co-author Carl Simpson at the University of Colorado Boulder argue that the environmental DNA used to establish their updated timeline is more complex than previously recognized.

Tuesday, November 29, 2022

A pair of lizard ‘kings’ from the old, old West

This photograph shows two blocks containing the holotype of Microteras borealis. It consists of a portion of the snout (left) and the braincase (right).
Resized Image using AI by SFLORG
Photo Credit: Courtesy of the Yale Peabody Museum of Natural History

Yale researchers have identified the oldest-known, definitive members of the lizard crown group that includes all living lizards and their closest extinct relatives.

The two new species, Eoscincus ornatus and Microteras borealis, fill important gaps in the fossil record and offer tantalizing clues about the complexity and geographic distribution of lizard evolution. The new lizard “kings” are described in a study published in Nature Communications.

“This helps us time out the ages of the major living lizard and snake groups, as well as when their key anatomical features originated,” said Chase Brownstein, first author of the study. Brownstein, a Yale senior, collaborated on the study with Yale paleontologists Jacques Gauthier and Bhart-Anjan S. Bhullar.

Gauthier is a professor of Earth and planetary sciences in Yale’s Faculty of Arts and Science and curator at the Yale Peabody Museum of Natural History. Bhullar is an associate professor of Earth & planetary sciences and an associate curator at the Peabody Museum.

Monday, November 28, 2022

Ancient Iowan super predator got big by front-loading its growth in its youth

Co-author Ben Otoo with a life-size illustration of Whatcheeria.
Photo Credit: Courtesy of Ben Otoo.

The Field Museum in Chicago is home to the best, most-complete fossils of a prehistoric superpredator-- but one that lived hundreds of millions of years before SUE the T. rex. Whatcheeria was a six-foot-long lake-dwelling creature with a salamander-like body and a long, narrow head; its fossils were discovered in a limestone quarry near the town of What Cheer, Iowa. There are around 350 Whatcheeria specimens, ranging from single bones to complete skeletons, that have been unearthed, and every last one of them resides in the Field Museum’s collections. In a new study in Communications Biology, these specimens helped reveal how Whatcheeria grew big enough to menace its fishy prey: instead of growing “slow and steady” the way that many modern reptiles and amphibians do, it grew rapidly in its youth.

“If you saw Whatcheeria in life, it would probably look like a big crocodile-shaped salamander, with a narrow head and lots of teeth,” says Ben Otoo, a co-author of the study and a PhD student at the University of Chicago and the Field Museum. “If it really curled up, probably to an uncomfortable extent, it could fit in your bathtub, but neither you nor it would want it to be there.”

Wednesday, November 23, 2022

World’s oldest meal offers food for thought

Professor Jochen Brocks (left) and Dr Ilya Bobrovskiy
Photo Credit: ANU

The contents of the last meal consumed by the earliest animals known to inhabit Earth more than 550 million years ago has unearthed new clues about the physiology of our earliest animal ancestors, according to scientists from The Australian National University (ANU).

Ediacara biota are the world's oldest large organisms and were first discovered in the Ediacara Hills in South Australia's Flinders Ranges. They date back 575 million years.

ANU researchers found the animals ate bacteria and algae that was sourced from the ocean floor. The findings, published in Current Biology, reveal more about these strange creatures, including how they were able to consume and digest food.

The scientists analyzed ancient fossils containing preserved phytosterol molecules -- a type of fat found in plants -- that remained from the animals' last meal. By examining the molecular remains of what the animals ate, the researchers were able to confirm the slug-like organism, known as Kimberella, had a mouth and a gut and digested food the same way modern animals do. The researchers say it was likely one of the most advanced creatures of the Ediacarans.

Monday, November 21, 2022

Scientists estimate the weight of two giant extinct amphibians

Artist’s reconstruction of Eryops megacephalus (left) and Paracyclotosaurus davidi (right).
Image Credit: Josè Vitor Silva.

A team of Australian scientists led by UNSW Sydney paleontologist Lachlan Hart has calculated the body mass of two ancient amphibians.

The last of the temnospondyls – amphibians that look more like crocodiles – became extinct during the Cretaceous period, about 120 million years ago, after thriving on Earth for more than 200 million years.

Now a team of scientists led by Lachlan Hart, a paleontologist and PhD candidate in the School of Biological, Earth & Environmental Sciences at UNSW Sydney, has assessed various methods of estimating the weight of these unique extinct animals. The team’s study is published in the journal Paleontology.

“Estimating mass in extinct animals presents a challenge, because we can’t just weigh them like we could with a living thing,” said Mr. Hart. “We only have the fossils to tell us what an animal looked like, so we often need to look at living animals to get an idea about soft tissues, such as fat and skin.”

Friday, November 18, 2022

Rapid fluctuations in oxygen levels coincided with Earth’s first mass extinction

Nevin Kozik during fieldwork to investigate how rapid changes in marine oxygen levels may have played a significant role in driving Earth’s first mass extinction.
Photo Credit: Courtesy of Nevin Kozik

Rapid changes in marine oxygen levels may have played a significant role in driving Earth’s first mass extinction, according to a new study led by Florida State University researchers.

About 443 million years ago, life on Earth was undergoing the Late Ordovician mass extinction, or LOME, which eliminated about 85% of marine species. Scientists have long studied this mass extinction and continue to investigate its possible causes, such as reduced habitat loss in a rapidly cooling world or persistent low-oxygen conditions in the oceans.

By measuring isotopes of the element thallium — which shows special sensitivity to changes in oxygen in the ancient marine environment — the research team found that previously documented patterns of this mass extinction coincided with an initial rapid decrease in marine oxygen levels followed by a rapid increase in oxygen. Their work is published online in the journal Science Advances.

“Paleontologists have noted that there were several groups of organisms, such as graptolites and brachiopods, that started to decline very early in this mass extinction interval, but we didn’t really have any good evidence of an environmental or climate signature to tie that early decline of these groups to a particular mechanism,” said co-author Seth Young, an associate professor in the Department of Earth, Ocean and Atmospheric Science. “This paper can directly link that early phase of extinction to changes in oxygen. We see a marked change in thallium isotopes at the same time these organisms start their steady decline into the main phase of the mass extinction event.”

Tuesday, November 15, 2022

Prehistoric predator? Artificial intelligence says no

Artificial intelligence has proven vital in identifying a mysterious Aussie dinosaur
Image Credit: Dr Anthony Romilio

Artificial intelligence has revealed that prehistoric footprints thought to be made by a vicious dinosaur predator were in fact from a timid herbivore.

In an international collaboration, University of Queensland paleontologist Dr Anthony Romilio used AI pattern recognition to re-analyze footprints from the Dinosaur Stampede National Monument, south-west of Winton in Central Queensland.

“Large dinosaur footprints were first discovered back in the 1970s at a track site called the Dinosaur Stampede National Monument, and for many years they were believed to be left by a predatory dinosaur, like Australovenator, with legs nearly two meters long,” said Dr Romilio.

“The mysterious tracks were thought to be left during the mid-Cretaceous Period, around 93 million years ago.

“But working out what dino species made the footprints exactly – especially from tens of millions of years ago – can be a pretty difficult and confusing business.

Friday, November 11, 2022

Researchers Solve Hundred-Year-Old Botanical Mystery that was Key to the Spread of Plant Life on Land

Plant material from Yale-Myers Forest and YSE greenhouses were used to study how their vascular systems are constructed and how they compare to the extinct plants from the fossil record. Without developing their vascular systems, plants would largely still look like mosses. Shown here: Huperzia lucidula, also known as Shining club-moss.
Photo Credit: courtesy of Craig Brodersen Lab.

The earliest land plants were small — just a few centimeters tall at most — and restricted to moist, boggy habitats around streams and ponds. Around 400 million years ago, however, plants developed vascular systems to extract water more efficiently from the soil and use it for photosynthesis, a transition that would forever alter the Earth’s atmosphere and ecosystems. A team of researchers have now solved a 100-year-old paleontology mystery: How did ancient plants emerge from swamps and riverbanks to new habitats with limited access to water?

In a new paper published in Science, YSE Professor of Plant Physiological Ecology Craig Brodersen and his research team, including lead author Martin Bouda ’17 PhD, ’12 MPhil and Kyra A. Prats ’22 PhD, ’16 MFS, discovered that a simple change in the vascular system of plants made them more drought-resistant, which opened up new landscapes for exploration.

The research was spurred by a century-long debate about why the simple, cylindrical vascular system of the earliest land plants rapidly changed to more complex shapes. In the 1920s, scientists noted this increasing complexity in the fossil record but were not able to pinpoint the reason — if there even was one — for the evolutionary changes.

New pterosaur species found in sub-Saharan Africa

SMU paleontologists helped find a new species of pterosaurs in Angola, where fossils of other large marine animals have been found. E. otyikokolo can be seen flying above the ocean in the ancient picture.
Artwork Credit: Karen Carr Studio.

With wings spanning nearly 16 feet, a new species of pterosaurs has been identified from the Atlantic coast of Angola.

An international team, including two vertebrate paleontologists from SMU, named the new genus and species Epapatelo otyikokolo. This flying reptile of the dinosaur age was found in the same region of Angola as fossils from large marine animals currently on display at the Smithsonian’s National Museum of Natural History.

Pterosaur fossils that date back to the Late Cretaceous are extremely rare in sub-Saharan Africa, said team member Michael J. Polcyn, research associate in the Huffington Department of Earth Sciences and senior research fellow, ISEM at SMU (Southern Methodist University).

“This new discovery gives us a much better understanding of the ecological role of the creatures that were flying above the waves of Bentiaba, on the west coast of Africa, approximately 71.5 million years ago,” Polcyn said.

Renowned paleontologist Louis L. Jacobs, SMU professor emeritus of earth sciences and president of ISEM, an interdisciplinary institute at the university, also collaborated on the research. The team’s findings were published in the journal Diversity.

Wednesday, November 2, 2022

500 million year-old fossils reveal answer to evolutionary riddle

Fossil specimen (left) and diagram (right) of Gangtoucunia aspera preserving soft tissues, including the gut and tentacle.
Image Credit: Luke Parry and Guangxu Zhang.

An exceptionally well-preserved collection of fossils discovered in eastern Yunnan Province, China, has enabled researchers to solve a centuries-old riddle in the evolution of life on earth, revealing what the first animals to make skeletons looked like. The results have been published today in Proceedings of the Royal Society B.

The first animals to build hard and robust skeletons appear suddenly in the fossil record in a geological blink of an eye around 550-520 million years ago during an event called the Cambrian Explosion. Many of these early fossils are simple hollow tubes ranging from a few millimetres to many centimetres in length. However, what sort of animals made these skeletons was almost completely unknown, because they lack preservation of the soft parts needed to identify them as belonging to major groups of animals that are still alive today.

The new collection of 514-million-year-old fossils includes four specimens of Gangtoucunia aspera with soft tissues still intact, including the gut and mouthparts. These reveal that this species had a mouth fringed with a ring of smooth, unbranched tentacles about 5 mm long. It’s likely that these were used to sting and capture prey, such as small arthropods. The fossils also show that Gangtoucunia had a blind-ended gut (open only at one end), partitioned into internal cavities, that filled the length of the tube.

Monday, October 3, 2022

Jurassic ichthyosaurs divided food resources to co-exist, researchers find

The skull of Ichthyosaurs Hauffiopteryx typicus from the Strawberry Bank Lagerstätt, one of the specimens that were the subject of this study.
Credit: Bath Royal Literary and Scientific Institution Collections

Early Jurassic ichthyosaur juveniles show predatory specializations, scientists at the University of Bristol have revealed.

Their findings, published today in Journal of Anatomy, suggest that physical differences in their snouts show they evolved to have different diets and were not competing for the same resource.

Ichthyosaurs, the classic ‘sea dragons’, were dolphin-shaped marine predators that fed on fish and squid-like swimming shellfish. The ichthyosaurs of the Lower Jurassic, some 185 million years ago, are renowned because the first specimens were found over 200 years ago at Lyme Regis in southern England, by the celebrated fossil collector and paleontologist Mary Anning. Some of her specimens have long, slender snouts and others have short, broad snouts.

“Functional studies need excellent three-dimensional specimens,” said Matt Williams of Bath Royal Literary and Scientific Institution, “and the Lower Jurassic ichthyosaur fossils from Strawberry Bank in Ilminster are just that. Mary Anning’s fossils are amazing, but they are mostly squashed flat.”

Saturday, October 1, 2022

What caused the holes in SUE the T. rex ’s jaw? Probably not an infection

Field Museum paleontologist Jingmai O’Connor with SUE the T. rex’s skull.
Resized Image using AI by SFLORG
Credit: Katharine Uhrich, Field Museum

SUE the T. rex is one of the most complete, best-preserved Tyrannosaurus rex specimens ever found. That level of preservation helps reveal details about SUE’s life. For instance, SUE lived to a ripe old age of about thirty-three, and in those years, suffered their fair share of injuries. SUE’s most mysterious ailment might be the holes in their jawbone. These holes, some the diameter of a golf ball, dot the back half of the left lower jaw. It’s not clear what caused them, but similar injuries have been found in other T. rex fossils. In a new study published in Cretaceous Research, scientists showed that one of the popular theories-- that SUE had suffered an infection from a protozoan parasite-- couldn’t be true.

“These holes in SUE’s jaw have been a mystery for decades,” says Jingmai O’Connor, the associate curator of fossil reptiles at Chicago’s Field Museum and a co-author of the study. “Nobody knows how they formed, and there have been lots of guesses.”

One early hypothesis was that SUE suffered from a fungus-like bacterial infection, but that was later shown to be unlikely. It was re-hypothesized that SUE had a protozoan infection. Protozoans are microbes with more complex cell structures than bacteria. There are lots of protozoan-caused maladies out there; one common such disease is called trichomoniasis, caused by a microbe called Trichomonas vaginalis. Humans can get infected with trichomoniasis as an STD, but other animals can catch it too.

What a reptile’s bones can teach us about Earth’s perilous past

An illustration of how Palacrodon may have looked.
Credit: K.M. Jenkins

An extinct reptile’s oddly shaped chompers, fingers, and ear bones may tell us quite a bit about the resilience of life on Earth, according to a new study.

In fact, paleontologists at Yale, Sam Houston State University, and the University of the Witwatersrand say the 250-million-year-old reptile, known as Palacrodon, fills in an important gap in our understanding of reptile evolution. It’s also a signal that reptiles, plants, and ecosystems may have fared better or recovered more quickly than previously thought after a mass extinction event wiped out most of the plant and animal species on the planet.

“We now know that Palacrodon comes from one of the last lineages to branch off the reptile tree of life before the evolution of modern reptiles,” said Kelsey Jenkins, a doctoral student in Yale’s Department of Earth and Planetary Sciences in the Faculty of Arts and Sciences and first author of the study, which appears in the Journal of Anatomy. “We also know that Palacrodon lived in the wake of the most devastating mass extinction in Earth’s history.”

That would be the Permian-Triassic extinction event, which occurred 252 million years ago. Known as “the Great Dying,” it killed off 70% of terrestrial species and 95% of marine species.

Although a large number of reptile species eventually bounced back from this extinction event, the details of how that happened are murky. Researchers have spent decades trying to fill in the gaps in our understanding of key adaptations that enabled reptiles to flourish after the Permian-Triassic extinction — and what those adaptations may reveal about the ecosystems where they lived.

Featured Article

Heat extremes in the soil are underestimated

Climate change intensifies extreme heat in the soil. Photo Credit: André Künzelmann (UFZ) For a long time, little attention was paid to soil...

Top Viewed Articles