Matching dinosaur footprints found on opposite sides of the Atlantic Ocean

An international team of researchers led by SMU paleontologist Louis L. Jacobs has found matching sets of Early Cretaceous dinosaur footprints on what are now two different continents.

More than 260 footprints were discovered in Brazil and in Cameroon, showing where land-dwelling dinosaurs were last able to freely cross between South America and Africa millions of years ago before the two continents split apart.

"We determined that in terms of age, these footprints were similar," Jacobs said. "In their geological and plate tectonic contexts, they were also similar. In terms of their shapes, they are almost identical."

The footprints, impressed into mud and silt along ancient rivers and lakes, were found more than 3,700 miles, or 6,000 kilometers, away from each other. Dinosaurs made the tracks 120 million years ago on a single supercontinent known as Gondwana -- which broke off from the larger landmass of Pangea, Jacobs said.

"One of the youngest and narrowest geological connections between Africa and South America was the elbow of northeastern Brazil nestled against what is now the coast of Cameroon along the Gulf of Guinea," Jacobs explained. "The two continents were continuous along that narrow stretch, so that animals on either side of that connection could potentially move across it."

Most of the dinosaur fossils were created by three-toed theropod dinosaurs.. A few were also likely made by sauropods or ornithischians, said Diana P. Vineyard, who is a research associate at SMU and co-author of the study.

Other co-authors of the study were Lawrence J. Flynn in the Department of Human Evolutionary Biology at Harvard University, Christopher R. Scotese in the Department of Earth and Planetary Sciences at Northwestern University and Ismar de Souza Carvalho at the Universidade Federal do Rio de Janeiro and Centro de Geociências.

The study was published by New Mexico Museum of Natural History & Science in a tribute to the late paleontologist Martin Lockley, who spent much of his career studying dinosaurs tracks and footprints.

Dinosaur footprints tell the whole story

Africa and South America started to split around 140 million years ago, causing gashes in Earth's crust called rifts to open up along pre-existing weaknesses. As the tectonic plates beneath South America and Africa moved apart, magma from the Earth's mantle rose to the surface, creating new oceanic crust as the continents moved away from each other. And eventually, the South Atlantic Ocean filled the void between these two newly-shaped continents.

Signs of some of those major events were evident between both locations where the dinosaur footprints were found -- at the Borborema region in the northeast part of Brazil and the Koum Basin in northern Cameroon. Half-graben basins -- geologic structures formed during rifting as the Earth's crust pulls apart and faults form -- are found in both areas and contain ancient river and lake sediments. Along with dinosaur tracks, these sediments contain fossil pollen that indicate an age of 120 million years.

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Early mammals lived longer

What distinguishes the growth and development patterns of early mammals of the Jurassic period? This is the question jointly investigated by researchers of Queen Mary University of London and the University of Bonn. Paleontologists have been able to gauge the lifespan and growth rates of these ancient animals, and even when they reached sexual maturity, by studying growth rings in fossilized tooth roots. The study has now been published in the journal Science Advances.

"Never before have we been able to reconstruct the growth patterns of these early mammals in such detail," says lead author Dr. Elis Newham, a postdoc at Queen Mary University of London who during the study was an Alexander von Humboldt Research Fellow at the University of Bonn, up to March 31, 2024.

For the study, the team analyzed fossilized tooth roots of mammal species from the Early to Late Jurassic periods (200-150 million years ago) found at three separate sites. The finds made in Wales are of some of the oldest known mammalian precursors from the Early Jurassic period, while the fossils found in Oxfordshire, UK are of a very broad array of coexisting early mammals. The fossils from the third site in Portugal date from the Late Jurassic.

Fossil tooth roots X-rayed

The research team studied the fossils using a technique called synchrotron X-ray tomography in which electrons are accelerated to near light speed (unlike regular X-ray imaging). The technique affords several advantages, starting with the fact that the fossils no longer have to be prepared, i.e. cut up into slices, so they can be analyzed whole. Furthermore, images obtained via synchrotron X-ray tomography are of higher quality than images from conventional X-ray microtomography.

Researchers were able to image tiny growth rings in fossilized root cement -- the bone tissue that attaches the teeth to the jaw. "The rings are similar to those in trees, but on a microscopic level," explains Professor Thomas Martin of the Vertebrates -- Mammals working group at the University of Bonn Institute of Organismic Biology, who is a senior author of the study. "Counting the rings and analyzing their thickness and texture enabled us to reconstruct the growth patterns and lifespans of these extinct animals."

The researchers determined that the first signs of the growth patterns characteristic of modern mammals, such as a puberty growth spurt, started emerging roughly 150 million years ago. Early mammals grew much more slowly but lived substantially longer than today's small mammals, with lifespans of eight to fourteen years instead of just one or two as in modern mice, for example. However, it took early mammals years to reach sexual maturity, again in contrast to their modern descendants which reach sexual maturity in just a few months.

"Our findings suggest that the distinctive life history patterns of mammals, characterized by high metabolic rates and extended parental care phases for example, have evolved over millions of years," Dr. Elis Newham explains, "The Jurassic period appears to have been a crucial time for this shift."

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The double-fanged adolescence of saber-toothed cats

The fearsome, saber-like teeth of Smilodon fatalis -- California's state fossil -- are familiar to anyone who has ever visited Los Angeles' La Brea Tar Pits, a sticky trap from which more than 2,000 saber-toothed cat skulls have been excavated over more than a century.

Though few of the recovered skulls had sabers attached, a handful exhibited a peculiar feature: the tooth socket for the saber was occupied by two teeth, with the permanent tooth slotted into a groove in the baby tooth.

Paleontologist Jack Tseng, associate professor of integrative biology at the University of California, Berkeley, doesn't think the double fangs were a fluke.

Nine years ago, he joined a few colleagues in speculating that the baby tooth helped to stabilize the permanent tooth against sideways breakage as it erupted. The researchers interpreted growth data for the saber-toothed cat to imply that the two teeth existed side by side for up to 30 months during the animal's adolescence, after which the baby tooth fell out.

In a new paper accepted for publication in the journal The Anatomical Record, Tseng provides the first evidence that the saber tooth alone would have been increasingly vulnerable to lateral breakage during eruption, but that a baby or milk tooth alongside it would have made it much more stable. The evidence consists of computer modeling of saber-tooth strength and stiffness against sideways bending, and actual testing and breaking of plastic models of saber teeth.

"This new study is a confirmation -- a physical and simulation test -- of an idea some collaborators and I published a couple of years ago: that the timing of the eruption of the sabers has been tweaked to allow a double-fang stage," said Tseng, who is a curator in the UC Museum of Paleontology. "Imagine a timeline where you have the milk canine coming out, and when they finish erupting, the permanent canine comes out and overtakes the milk canine, eventually pushing it out. What if this milk tooth, for the 30 or so months that it was inside the mouth right next to this permanent tooth, was a mechanical buttress?"

He speculates that the unusual presence of the baby canine -- one of the deciduous teeth all mammals grow and lose by adulthood -- long after the permanent saber tooth erupted protected the saber while the maturing cats learned how to hunt without damaging them. Eventually, the baby tooth would fall out and the adult would lose the saber support, presumably having learned how to be careful with its saber. Paleontologists still do not know how saber-toothed animals like Smilodon hunted prey without breaking their unwieldy sabers.

"The double-fang stage is probably worth a rethinking now that I've shown there's this potential insurance policy, this larger range of protection," he said. "It allows the equivalent of our teenagers to experiment, to take risks, essentially to learn how to be a full-grown, fully fledged predator. I think that this refines, though it doesn't solve, thinking about the growth of saber tooth use and hunting through a mechanical lens."

The study also has implications for how saber-toothed cats and other saber-toothed animals hunted as adults, presumably using their predatory skills and strong muscles to compensate for vulnerable canines.

Beam theory

Thanks to the wealth of saber-toothed cat fossils, which includes many thousands of skeletal parts in addition to skulls, unearthed from the La Brea Tar Pits, scientists know a lot more about Smilodon fatalis than about any other saber-toothed animal, even though at least five separate lineages of saber-toothed animals evolved around the world. Smilodon roamed widely across North America and into Central America, going extinct about 10,000 years ago.

Yet paleontologists are still confounded by that fact that adult animals with thin-bladed knives for canines apparently avoided breaking them frequently despite the sideways forces likely generated during biting. One study of the La Brea predator fossils found that during periods of animal scarcity, saber-toothed cats did break their teeth more often than in times of plenty, perhaps because of altered feeding strategies.

The double-fanged specimens from La Brea, which have been considered rare cases of individuals with delayed loss of the baby tooth, gave Tseng a different idea -- that they had an evolutionary purpose. To test his hypothesis, he used beam theory -- a type of engineering analysis employed widely to model structures ranging from bridges to building materials -- to model real-life saber teeth. This is combined with finite element analysis, which uses computer models to simulate the sideways forces a saber tooth could withstand before breaking.

"According to beam theory, when you bend a blade-like structure laterally sideways in the direction of their narrower dimension, they are quite a lot weaker compared to the main direction of strength," Tseng said. "Prior interpretations of how saber tooths may have hunted use this as a constraint. No matter how they use their teeth, they could not have bent them a lot in a lateral direction."

He found that while the saber's bending strength -- how much force it can withstand before breaking -- remained about the same throughout its elongation, the saber's stiffness -- its deflection under a given force -- decreased with increasing length. In essence, as the tooth got longer, it was easier to bend, increasing the chance of breakage.

By adding a supportive baby tooth in the beam theory model, however, the stiffness of the permanent saber kept pace with the bending strength, reducing the chance of breaking.

"During the time period when the permanent tooth is erupting alongside the milk one, it is around the time when you switch from maximum width to the relatively narrower width, when that tooth will be getting weaker," Tseng said. "When you add an additional width back into the beam theory equation to account for the baby saber, the overall stiffness more closely aligned with theoretical optimal."

Though not reported in the paper, he also 3D-printed resin replicas of saber teeth and tested their bending strength and stiffness on a machine designed to measure tensile strength. The results of these tests mirrored the conclusions from the computer simulations. He is hoping to 3D-print replicas from more life-like dental material to more accurately simulate the strength of real teeth.

Tseng noted that the same canine stabilization system may have evolved in other saber-toothed animals. While no examples of double fangs in other species have been found in the fossil record, some skulls have been found with adult teeth elsewhere in the jaws but milk teeth where the saber would erupt.

"What we do see is milk canines preserved on specimens with otherwise adult dentition, which suggests a prolonged retention of those milk canines while the adult tooth, the sabers, are either about to erupt or erupting," he said.

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Paleontologists unearth what may be the largest known marine reptile

The fossilised remains of a second gigantic jawbone measuring more than two metres long has been found on a beach in Somerset, UK.

Experts have identified the bones as belonging to the jaws of a new species of enormous ichthyosaur, a type of prehistoric marine reptile. Estimates suggest the oceanic titan would have been more than 25 metres long.

Father and daughter, Justin and Ruby Reynolds from Braunton, Devon, found the first pieces of the second jawbone to be found in May 2020, while searching for fossils on the beach at Blue Anchor, Somerset. Ruby, then aged 11, found the first chunk of giant bone before searching together for additional pieces.

Realising they had discovered something significant, they contacted leading ichthyosaur expert, Dr Dean Lomax, a palaeontologist at The University of Manchester. Dr Lomax, who is also a 1851 Research Fellow at the University of Bristol, contacted Paul de la Salle, a seasoned fossil collector who had found the first giant jawbone in May 2016 from further along the coast at Lilstock.

Dr Dean Lomax said: "I was amazed by the find. In 2018, my team (including Paul de la Salle) studied and described Paul's giant jawbone and we had hoped that one day another would come to light. This new specimen is more complete, better preserved, and shows that we now have two of these giant bones -- called a surangular -- that have a unique shape and structure. I became very excited, to say the least."

Justin and Ruby, together with Paul, Dr Lomax, and several family members, visited the site to hunt for more pieces of this rare discovery. Over time, the team found additional pieces of the same jaw which fit together perfectly, like a multimillion-year-old jigsaw.

Justin said: "When Ruby and I found the first two pieces we were very excited as we realised that this was something important and unusual. When I found the back part of the jaw, I was thrilled because that is one of the defining parts of Paul's earlier discovery."

The last piece of bone was recovered in October 2022.

The research team, led by Dr Lomax, revealed that the jaw bones belong to a new species of giant ichthyosaur that would have been about the size of a blue whale. Comparing the two examples of the same bone with the same unique features from the same geologic time zone supports their identifications.

The team have called the new genus and species Ichthyotitan severnensis, meaning "giant fish lizard of the Severn."

The bones are around 202 million years old, dating to the end of the Triassic Period in a time known as the Rhaetian. During this time, the gigantic ichthyosaurs swam the seas while the dinosaurs walked on land. It was the titans' final chapter, however -- as the story told in the rocks above these fossils record a cataclysm known as the Late Triassic global mass extinction event. After this time, giant ichthyosaurs from the family known as Shastasauridae go extinct. Today, these bones represent the very last of their kind.

Ichthyotitan is not the world's first giant ichthyosaur, but de la Salles' and Reynolds' discoveries are unique among those known to science. These two bones appear roughly 13 million years after their latest geologic relatives, including Shonisaurus sikanniensis from British Columbia, Canada, and Himalayasaurus tibetensis from Tibet, China.

Dr Lomax added: "I was highly impressed that Ruby and Justin correctly identified the discovery as another enormous jawbone from an ichthyosaur. They recognised that it matched the one we described in 2018. I asked them whether they would like to join my team to study and describe this fossil, including naming it. They jumped at the chance. For Ruby, especially, she is now a published scientist who not only found but also helped to name a type of gigantic prehistoric reptile. There are probably not many 15-year-olds who can say that! A Mary Anning in the making, perhaps."

Ruby said: "It was so cool to discover part of this gigantic ichthyosaur. I am very proud to have played a part in a scientific discovery like this."

Further examinations of the bones' internal structures have been carried out by master's student, Marcello Perillo, from the University of Bonn, Germany. His work confirmed the ichthyosaur origin of the bones and revealed that the animal was still growing at the time of death.

He said: "We could confirm the unique set of histological characters typical of giant ichthyosaur lower jaws: the anomalous periosteal growth of these bones hints at yet to be understood bone developmental strategies, now lost in the deep time, that likely allowed late Triassic ichthyosaurs to reach the known biological limits of vertebrates in terms of size. So much about these giants is still shrouded by mystery, but one fossil at a time we will be able to unravel their secret."

Concluding the work, Paul de la Salle added: "To think that my discovery in 2016 would spark so much interest in these enormous creatures fills me with joy. When I found the first jawbone, I knew it was something special. To have a second that confirms our findings is incredible. I am overjoyed."

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Slimming down a colossal fossil whale

A 30 million year-old fossil whale may not be the heaviest animal of all time after all, according to a new analysis by paleontologists at UC Davis and the Smithsonian Institution. The new analysis puts Perucetus colossus back in the same weight range as modern whales and smaller than the largest blue whales ever recorded. The work is published Feb. 29 in PeerJ.

A fossil skeleton of Perucetus was discovered in Peru and described in a paper in Nature last year.

The animal lived about 39 million years ago and belonged to an extinct group of early whales called the basilosaurids.

Perucetus' bones are unusually dense. Mammal bones usually have a solid exterior and are spongy or hollow in the center.

Some animals have more of the center filled in with solid bone, making them dense and heavy.

In aquatic animals, heavy bones can offset buoyancy from body fat and blubber, allowing the animal to maintain neutral buoyancy in water or -- in the case of the hippopotamus -- to walk on river beds.

The fossil whale bones have both extensive in-filling and extra growth of bone on the outside as well, a condition called pachyostosis also seen in some modern aquatic mammals, such as manatees.

Based on a series of assumptions, the original authors (Giovanni Bianucci at the University of Pisa, Italy and colleagues) estimated a body mass for Perucetus of 180 metric tons (ranging from 85 to 340 metric tons). This would make Perucetus as heavy as, or heavier than the biggest blue whales known, even though it is considerably shorter at 17 meters long compared to a blue whale at about 30 meters.

How to weigh a whale?

Professor Ryosuke Motani, a paleobiologist at the UC Davis Department of Earth and Planetary Sciences, said that these estimates would make Perucetus impossibly dense.

"It would have been a job for the whale to stay at the surface, or even to leave the sea bottom -- it would have required continuous swimming against the gravity to do anything in the water," Motani said.

Motani and Nick Pyenson at the Smithsonian Institute National Museum of Natural History reexamined the assumptions used to make those estimates.

The first problem is that Bianucci et al used the fossil bones to estimate the weight of the skeleton, then extrapolated to the weight of the entire animal, assuming that the skeletal and non-skeletal mass would scale at the same rate with increasing body size.

But measurements of other animals show this is not the case, Motani and Pyenson argue.

The original estimates also overestimated how much overall body mass increases as a result of pachyostosis.

But evidence from manatees shows that their bodies are relatively light relative to their skeletal mass.

Motani and Pyenson estimate that the 17-meter long Perucetus weighed in at 60 to 70 tons, considerably less than the known weights of blue whales.

A Perucetus that grew to 20 meters could weigh over 110 tons, still well short of the largest blue whales at 270 tons.

"The new weight allows the whale to come to the surface and stay there while breathing and recovering from a dive, like most whales do," Motani said.

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Mysterious fruit shown to be the oldest known fossils of the Frankincense and Myrrh family

Early in the 1970s, a paleontologist working on the outskirts of an Indian village found small, bead-like fossils embedded in the gray chert dotting the surrounding fields. The site was notorious for turning up plant fossils that were difficult to identify, including the fruit of an extinct species resignedly given the name "Enigmocarpon." The new fossils proved just as frustratingly intractable; more of them were discovered in India over the next several decades, but scientists had little luck deciding what type of plant they belonged to.

Now, researchers say they've solved the mystery. Using CT scanning technology, Steven Manchester, curator of paleobotany at the Florida Museum of Natural History, created 3D reconstructions of the original fossil specimens and others collected since.

He showed these to a colleague, who noticed something odd about the five triangular seeds inside.

"When I showed him the 3D images, he said "those aren't seeds.

Pyrenes are woody dispersal pods that give seeds an extra layer of protection.

Examples include the hard stones at the cores of cherries, peaches, dates and pistachios, which prevent the seeds from being digested along with the rest of the fruit.

Distinguishing a seed from a pyrene, especially when they're the size of snowflakes, requires close scrutiny.

Traditional methods of paleobotany, which involve incrementally dissolving fossils in acid and observing each new layer under a microscope, had proven insufficient.

"If we had specimens that fractured at just the right plane, I would have been able to recognize them, but with the material we had on hand, I couldn't tell," Manchester said.

There are only a few plant groups that produce pyrenes, fewer still with fruits that contain five seeds arranged in a pentagram.

Through a process of elimination, Manchester and Judd determined the fossils belonged to an extinct species in Burseraceae, the Frankincense family.

Fossilized wood, leaves, fruits and flowers from this family have been found elsewhere in India, often sandwiched between thick slabs of basalt created by one of the largest volcanic eruptions in Earth's history.

At the time, India was an island off the southeast coast of Africa.

India's continental plate was slowly inching toward Europe and Asia, and as it rafted past Madagascar, it broke the seal on a thin layer of Earth's crust.

Rivers of liquid rock poured onto a landscape the size of California and Texas combined.

The eruptions occurred intermittently for nearly a million years, and they repeatedly killed any vegetation that grew during the interludes.

"The fossils were preserved at times of quiet between the eruptions," Manchester said.

"Ponds and lakes formed on the relatively fresh lava flows, and vegetation, including wood and seeds, were washed into them and covered by sediment."

The shield volcano responsible for the destruction was active just before and after the asteroid impact that drew the curtains on the Cretaceous, and both are thought to have contributed to the extinctions that followed.

Most fossils from the Frankincense family have, up until now, been recovered from rocks that postdate the asteroid impact.

The original fruits discovered in the 1970s were fossilized before that event.

This makes them the oldest Burseraceae fossils discovered to date, which has important implications for the family's origin.

Scientists have a good idea of when plants in the group initially evolved, but it's still unclear where they came from.

Ancient species of Burseraceae are a common component of fossil beds in southern England, the Czech Republic and parts of North America.

Beginning roughly 50 million years ago, however, Earth's climate began a long cooling process that ultimately resulted in the most recent Ice Ages.

As temperatures fell, species in the Frankincense family seemed to reverse their preference for hemispheres.

Today, there are more than 700 Burseraceae species, and most of them grow south of the equator.

The ancestors of modern Burseraceae species are thought to have first appeared somewhere in the north.

Alternatively, a few early species may have had a global distribution but became isolated as continents drifted apart.

The fossils from India suggest the southern hemisphere may have been the real birthplace of the family.

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Fossils tell tale of last primate to inhabit North America before humans

The story of Ekgmowechashala, the final primate to inhabit North America before Homo sapiens or Clovis people, reads like a spaghetti western: A grizzled and mysterious loner, against the odds, ekes out an existence on the American Plains.

Except this tale unfolded about 30 million years ago, just after the Eocene-Oligocene transition during which North America saw great cooling and drying, making the continent less hospitable to warmth-loving primates.

Today, paleontologists from the University of Kansas and the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing have published evidence in the Journal of Human Evolution shedding light on the long-standing saga of Ekgmowechashala, based on fossil teeth and jaws found in both Nebraska and China.

To do so, the researchers first had to reconstruct its family tree, a job helped by the discovery of an even more ancient Chinese "sister taxon" of Ekgmowechashala the team has named Palaeohodites (or "ancient wanderer"). The Chinese fossil discovery resolves the mystery of Ekgmowechashala's presence in North America, showing it was an immigrant rather than the product of local evolution.

"This project focuses on a very distinctive fossil primate known to paleontologists since the 1960s," said lead author Kathleen Rust, a doctoral candidate in paleontology at KU's Biodiversity Institute and Natural History Museum. "Due to its unique morphology and its representation only by dental remains, its place on the mammalian evolutionary tree has been a subject of contention and debate. There's been a prevailing consensus leaning towards its classification as a primate. But the timing and appearance of this primate in the North American fossil record are quite unusual. It appears suddenly in the fossil record of the Great Plains more than 4 million years after the extinction of all other North American primates, which occurred around 34 million years ago."

In the 1990s, Rust's doctoral adviser and co-author Chris Beard, KU Foundation Distinguished Professor and senior curator of vertebrate paleontology, collected fossils from the Nadu Formation in the Baise Basin in Guangxi, China, that closely resembled the Ekgmowechashala material known from North America. By that time, Ekgmowechashala was notoriously enigmatic among North American paleontologists.

"When we were working there, we had absolutely no idea that we would find an animal that was closely related to this bizarre primate from North America, but literally as soon as I picked up the jaw and saw it, I thought, 'Wow, this is it,'" Beard said. "It's not like it took a long time, and we had to undertake all kinds of detailed analysis -- we knew what it was. Here in KU's collection, we have some critical fossils, including what is still by far the best upper molar of Ekgmowechashala known from North America. That upper molar is so distinctive and looks quite similar to the one from China that we found that it kind of seals the deal."

Beard left it to Rust to conduct the morphological analysis that tied Ekgmowechashala and its cousin Palaeohodites from China in a phylogenetic tree to establish their evolutionary relationships.

In the course of the work, Rust was able to draw conclusions about how Ekgmowechashala came to be discovered in Nebraska, millions of years after its fellow primates died out in the continent's fossil record.

"We collected a substantial amount of morphological data to create an evolutionary tree using a phylogenetic reconstruction software and algorithm," Rust said. "This evolutionary tree suggests a close evolutionary relationship between North American Ekgmowechashala and Palaeohodites from China, which Chris and his colleagues discovered in the 1990s. The results from our analysis unequivocally supports this hypothesis."

The KU researchers said their discovery is not only exciting in terms of discovering a new primate species from late Eocene China -- but also in settling the origin story of Ekgmowechashala. Based on their investigation, Ekgmowechashala did not descend from an older North American primate that somehow survived the cooler and drier conditions that caused other North American primates to go extinct. Rather, its ancestors crossed over the Beringian region millions of years later, anticipating the route followed by the first Native Americans much later in time.

"Our analysis dispels the idea that Ekgmowechashala is a relic or survivor of earlier primates in North America," Rust said. "Instead, it was an immigrant species that evolved in Asia and migrated to North America during a surprisingly cool period, most likely via Beringia."

Species like Ekgmowechashala that show up suddenly in the fossil record long after their relatives have died off are referred to as "Lazarus taxa" after the biblical figure who was raised from the dead.

"The 'Lazarus effect' in paleontology is when we find evidence in the fossil record of animals apparently going extinct -- only to reappear after a long hiatus, seemingly out of nowhere," Beard said. "This is the grand pattern of evolution that we see in the fossil record of North American primates. The first primates came to North America about 56 million years ago at the beginning of the Eocene, and they flourished on this continent for more than 20 million years. But they went extinct when climate became cooler and drier near the Eocene-Oligocene boundary, about 34 million years ago. Several million years later Ekgmowechashala shows up like a drifting gunslinger in a Western movie, only to be a flash in the pan as far as the long trajectory of evolution is concerned. After Ekgmowechashala is gone for more than 25 million years, Clovis people come to North America, marking the third chapter of primates on this continent. Like Ekgmowechashala, humans in North America are a prime example of the Lazarus effect."

Rust and Beard were joined in the work by co-authors Xijun Ni of the Chinese Academy of Sciences, Beijing, and Kristen Tietjen, scientific illustrator with the KU Biodiversity Institute and Natural History Museum.

According to Rust, the tale of Ekgmowechashala is worth people's attention because it happened in an era of profound environmental and climatic changes, much like our own that's driven by human activity.

"It's crucial to comprehend how past biota reacted to such shifts," she said. "In such situations, organisms typically either adapt by retreating to more hospitable regions with available resources or face extinction. Around 34 million years ago, all of the primates in North America couldn't adapt and survive. North America lacked the necessary conditions for survival. This underscores the significance of accessible resources for our non-human primate relatives during times of drastic climatic change."

The study is also a part of a larger story that represents the earliest chapters of our own evolutionary journey that ultimately led to our own species, Rust said.

Read more at Science Daily

New fossil flying reptile 'Elvis' takes flight

A new 145-million-year-old pterosaur (extinct flying reptiles that lived alongside the dinosaurs) was named today by a team of British, American and German researchers. The animal was nicknamed 'Elvis' when the fossil was first unearthed in Bavaria, Germany because of the giant pompadour-like bony crest on its skull.

Now the animal has been given a formal scientific name of Petrodactyle wellnhoferi. The name translates as 'Wellnhofer's stone-finger' honouring legendary German palaeontologist Peter Wellnhofer who spent his career working on German pterosaurs. Petrodactyle is a member of a group of pterosaurs called the ctenochasmatids that were mostly small filter feeders. Petrodactyle is a very complete skeleton with nearly every bone preserved and in remarkable detail.

Many pterosaurs are known with bony crests which they used primarily as sexual signals to other members of the species, but Pterodactyle has by far the largest crest even seen in a ctenochasmatid. Dr David Hone of Queen Mary University of London was the lead author on the study said, "Big though this crest is, we know that these pterosaurs had skin-like extensions attached to it, so in life Petrodactyle would have had an even larger crest."

The details of the specimen are especially clear under UV light which helps show the difference between the bones and the rock in which they are embedded, which under natural light are a very similar colour. René Lauer of the Lauer Foundation, an author on the study said, "The use of UV Induced Fluorescence digital photography provided the ability to discern fine structures small bones and provided additional information regarding the structures of the bony crest which aided in the interpretations and conclusions of this unique new species."

Petrodactyle was unusually large too. It has a wingspan of around 2 meters, but it was still an older 'teenager' by pterosaur standards and would have been even larger as a fully mature animal. Even so, it is one of the largest pterosaurs known from the Late Jurassic period. Bruce Lauer of the Lauer Foundation, an author on the study said "The specimen was located in a quarry which is producing scientifically important fossils that provide additional insights into Late Jurassic Pterosaurs. This research is a great example of the benefits of cooperation between amateur collectors, commercial fossil dealers, our Foundation and research scientists to advance science."

Like other ctenochasmatids, Petrodactyle was at home on the shore of shallow seas but might have ventured into estuaries or to lakes. It's long jaw with many small teeth would have been good for grabbing at small fish, shrimp and other aquatic prey. However, unlike most other ctenochasmatids, it had an expansion at the back of the skull to attach large jaw muscles and give it a stronger bite than many of its contemporaries. Frederik Spindler of the Dinosaurier Museum in Germany, an author on the study said, "It is amazing to document an increasingly wide range of adaptations. Pterosaurs were a fundamental part of the Jurassic ecology."

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Fossils reveal how ancient birds molted their feathers -- which could help explain why ancestors of modern birds survived when all the other dinosaurs died

Every bird you've ever seen -- every robin, every pigeon, every penguin at the zoo -- is a living dinosaur. Birds are the only group of dinosaurs that survived the asteroid-induced mass extinction 66 million years ago. But not all the birds alive at the time made it. Why the ancestors of modern birds lived while so many of their relatives died has been a mystery that paleontologists have been trying to solve for decades. Two new studies point to one possible factor: the differences between how modern birds and their ancient cousins molt their feathers.

Feathers are one of the key traits that all birds share. They're made of a protein called keratin, the same material as our fingernails and hair, and birds rely on them to fly, swim, camouflage, attract mates, stay warm, and protect against the sun's rays. But feathers are complex structures that can't be repaired, so as a means of keeping them in good shape, birds shed their feathers and grow replacements in a process called molting. Baby birds molt in order to lose their baby feathers and grow adult ones; mature birds continue to molt about once a year.

"Molt is something that I don't think a lot of people think about, but it is fundamentally such an important process to birds, because feathers are involved in so many different functions," says Jingmai O'Connor, associate curator of fossil reptiles at Chicago's Field Museum. "We want to know, how did this process evolve? How did it differ across groups of birds? And how has that shaped bird evolution, shaped the survivability of all these different clades?" Two of O'Connor's recent papers examine the molting process in prehistoric birds.

A paper in the journal Cretaceous Research published in May 2023 detailed the discovery of a cluster of feathers preserved in amber from a baby bird that lived 99 million years ago.

Today, baby birds are on a spectrum in terms of how developed they are when they're born and how much help they need from their parents. Altricial birds hatch naked and helpless; their lack of feathers means that their parents can more efficiently transmit body heat directly to the babies' skin. Precocial species, on the other hand, are born with feathers and are fairly self-sufficient.

All baby birds go through successive molts -- periods when they lose the feathers they have and grow in a new set of feathers, before eventually reaching their adult plumage. Molting takes a lot of energy, and losing a lot of feathers at once can make it hard for a bird to keep itself warm. As a result, precocial chicks tend to molt slowly, so that they keep a steady supply of feathers, while altricial chicks that can rely on their parents for food and warmth undergo a "simultaneous molt," losing all their feathers at roughly the same time.

The amber-preserved feathers in this study are the first definitive fossil evidence of juvenile molting, and they reveal a baby bird whose life history doesn't match any birds alive today. "This specimen shows a totally bizarre combination of precocial and altricial characteristics," says O'Connor, who was the first author of the paper alongside senior author Shundong Bi of the Indiana University of Pennsylvania. "All the body feathers are basically at the exact same stage in development, so this means that all the feathers started growing simultaneously, or near simultaneously." However, this bird was almost certainly part of a now-extinct group called the Enantiornithines, which O'Connor's previous work has shown were highly precocial.

O'Connor hypothesizes that the pressures of being a precocial baby bird that had to keep itself warm, while undergoing a rapid molt, might have been a factor in the ultimate doom of the Enantiornithines. "Enantiornithines were the most diverse group of birds in the Cretaceous, but they went extinct along with all the other non-avian dinosaurs," says O'Connor. "When the asteroid hit, global temperatures would have plummeted and resources would have become scarce, so not only would these birds have even higher energy demands to stay warm, but they didn't have the resources to meet them."

Meanwhile, an additional study published July 3 in Communications Biology by O'Connor and Field Museum postdoctoral researcher Yosef Kiat examines molting patterns in modern birds to better understand how the process first evolved.

In modern adult birds, molting usually happens once a year in a sequential process, in which they replace just a few of their feathers at a time over the course of a few weeks. That way, they're still able to fly throughout the molting process. Simultaneous molts in adult birds, in which all the flight feathers fall out at the same time and regrow within a couple weeks, are rarer and tend to show up in aquatic birds like ducks that don't absolutely need to fly in order to find food and avoid predators.

It's very rare to find evidence of molting in fossil birds and other feathered dinosaurs, and O'Connor and Kiat wanted to know why. "We had this hypothesis that birds with simultaneous molts, which occur in a shorter duration of time, will be less represented in the fossil record," says O'Connor -- less time spent molting means fewer opportunities to die during your molt and become a fossil showing signs of molting. To test their hypothesis, the researchers delved into the Field Museum's collection of modern birds.

"We tested more than 600 skins of modern birds stored in the ornithology collection of the Field Museum to look for evidence of active molting," says Kiat, the first author of the study. "Among the sequentially molting birds, we found dozens of specimens in an active molt, but among the simultaneous molters, we found hardly any."

While these are modern birds, not fossils, they provide a useful proxy. "In paleontology, we have to get creative, since we don't have complete data sets. Here, we used statistical analysis of a random sample to infer what the absence of something is actually telling us," says O'Connor. In this case, the absence of molting fossil birds, despite active molting being so prevalent in the sample of modern bird specimens, suggests that fossil birds simply weren't molting as often as most modern birds. They may have undergone a simultaneous molt, or they may not have molted on a yearly basis the way most birds today do.

Both the amber specimen and the study of molting in modern birds point to a common theme: prehistoric birds and feathered dinosaurs, especially ones from groups that didn't survive the mass extinction, molted differently from today's birds.

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Multiple species of semi-aquatic dinosaur may have roamed pre-historic Britain

Palaeontologists at the University of Southampton (UK) studying a British dinosaur tooth have concluded that several distinct groups of spinosaurs -- dinosaurs with fearsome crocodile-like skulls -- inhabited southern England over 100 million years ago.

The team, from the University's EvoPalaeoLab, carried out a series of tests on the 140 million year old tooth, discovered in the early 20th century, in a thick, complicated rock structure named the Wealden Supergroup. The Wealden lies across south-eastern England and was formed around 140-125 million years ago.

The scientists conducted statistical analysis on the tooth, which is stored at the Hastings Museum and Art Gallery in East Sussex. They meticulously compared its characteristics with other species in the spinosaur 'family' of dinosaurs to which it belongs. Their findings, published in the journal PeerJ, confirm the tooth doesn't match that of any identified spinosaur species.

Project supervisor, Dr Neil Gostling explains: "While we can't formally identify a new species from one tooth, we can say this spinosaur tooth doesn't match any of the existing species we know about. Given how many individual teeth exist in collections, this could be just the tip of the iceberg and it's quite possible that Britain may have once teemed with a diverse range of these semi-aquatic, fish-eating dinosaurs."

The Wealden is famous for its spinosaur fossils. Baryonyx -- discovered in Surrey in 1983 -- is one of the world's most significant spinosaur specimens, since it was the first to reveal the true appearance of this crocodile-headed group. Less impressive spinosaur remains -- isolated teeth -- are common throughout the Wealden, and have often been identified as belonging to Baryonyx. However, some experts have long suspected that this is incorrect.

"We used a variety of techniques to identify this specimen, in order to test whether isolated spinosaur teeth could be referred to Baryonyx," said lead author Chris Barker, whose PhD focuses on the spinosaurs of southern Britain. "The tooth did not group with Baryonyx in any of our data runs. It must belong to a different type of spinosaur."

The results show that distinct and distantly related spinosaur types lived in the region during Early Cretaceous times. This backs up research by the EvoPalaeoLab team, who argued in previous studies that the spinosaurs of southern England are more diverse than previously thought.

In 2021, they named the 'Hell Heron' Ceratosuchops from the Isle of Wight, and in 2022 announced the discovery of what might be Europe's largest ever land predator, a giant known only as the 'White Rock' spinosaur. These several spinosaurs did not all live at the same time, but inhabited the region over the course of more than 15 million years.

"Museums themselves are places to make exciting discoveries as our understanding of specimens changes from the time they were deposited," said Dr Neil Gostling. "What this work highlights is the importance of keeping collections alive, and developing our understanding of them. Curators are essential to help us navigate the cupboards and displays, helping us to unpick the often-incomplete records -- either never fully recorded, or lost to time. The diversity of palaeoenvironments is not always hidden in rocks, it is often waiting in a museum, its importance waiting to be rediscovered!"

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Quarter-ton marsupial roamed long distances across Australia's arid interior

One of Australia's first long-distance walkers has been described after Flinders University palaeontologists used advanced 3D scans and other technology to take a new look at the partial remains of a 3.5 million year old marsupial from central Australia.

They have named a new genus of diprotodontid Ambulator, meaning walker or wanderer, because the locomotory adaptations of the legs and feet of this quarter-tonne animal would have made it well suited to roam long distances in search of food and water when compared to earlier relatives.

Researchers say the skeleton of Ambulator keanei, found on the Australian Wildlife Conservancy's Kalamurina Station in northern South Australia by Flinders University researchers in 2017, belongs to a species in the family Diprotodontidae, a group of four-legged herbivores that were the largest marsupials to ever exist.

"Diprotodontids are distantly related to wombats -- the same distance as kangaroos are to possums -- so unfortunately there is nothing quite like them today. As a result, palaeontologists have had a hard time reconstructing their biology," says Jacob van Zoelen, a PhD candidate at the Flinders University Palaeontology Laboratory.

The largest species, Diprotodon optatum, grew to the size of a car, weighing up to 2.7 tonnes. Diprotodontids were an integral part of Australian ecosystems until the last species became extinct about 40,000 years ago.

During the period when Ambulator keanei was alive (the Pliocene), there was an increase in grasslands and open habitat as Australia became drier. Diprotodontids likely had to travel much greater distances to obtain enough food and water to keep them going.

"We don't often think of walking as a special skill but when you're big any movement can be energetically costly so efficiency is key," says Mr van Zoelen.

"Most large herbivores today such as elephants and rhinoceroses are digitigrade, meaning they walk on the tips of their toes with their heel not touching the ground.

"Diprotodontids are what we call plantigrade, meaning their heel-bone (calcaneus) contacts the ground when they walk, similar to what humans do. This stance helps distribute weight when walking but uses more energy for other activities such as running."

Diprotodontids display extreme plantigrady in their hands as well, by modifying a bone of the wrist, the pisiform, into a secondary heel, Mr van Zoelen explains.

This 'heeled hand' made early reconstructions of these animals look bizarre and awkward, he says.

"Development of the wrist and ankle for weight-bearing meant that the digits became essentially functionless and likely did not make contact with the ground while walking. This may be why no finger or toe impressions are observed in the trackways of diprotodontids.

"So, diprotodontids such as Ambulator may have evolved this morphology to traverse great distances more efficiently. This morphology also allowed for greater weight to be supported, allowing diprotodontids to get very big indeed.

"Eventually, this led to the evolution of the giant and relatively well-known Diprotodon."

Most studies on the group have focused on the skull, as associated skeletons are rare in the fossil record. As such, the newly described skeleton is of great importance and is even more special as it is the first to be found with associated soft tissue structures.

Using 3D-scanning technology, the Flinders team was able to compare the partial skeleton with other diprotodontid material from collections all over the world.

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Culprit behind destruction of New York's first dinosaur museum revealed

A new paper from the University of Bristol rewrites the history of the darkest, most bizarre event in the history of palaeontology.

In New York, in May of 1871, the partially built, life-size models of dinosaurs and other prehistoric creatures destined for a prestigious new museum in Central Park were totally destroyed in a violent act of malicious vandalism by a gang of thugs with sledgehammers. The shattered pieces were carted away and buried somewhere in the park, never to be seen again.

Until now, the heinous act had been tributed to former American politician William 'Boss' Tweed.

But now, a new paper from Ms Victoria Coules of Bristol's Department of History of Art and Professor Michael Benton of Bristol's School of Earth Sciences sheds new light on the incident and, contrary to previous accounts, identifies who was really behind the order and what drove them to such wanton destruction -- an odd man known as Henry Hilton, the Treasurer and VP of Central Park.

"It's all to do with the struggle for control of New York city in the years following the American Civil War (1861-1865)," said Ms Coules. "The city was at the centre of a power struggle -- a battle for control of the city's finances and lucrative building and development contracts."

As the city grew, the iconic Central Park was taking shape. More than just a green space, it was to have other attractions, including the Paleozoic Museum. British sculptor Benjamin Waterhouse Hawkins, who had created the Crystal Palace Dinosaurs, the life-size models of prehistoric creatures in London -- had travelled to America and was commissioned to build American versions of the models for the Paleozoic museum.

But the notorious William "Boss" Tweed had taken command of the city and, in sweeping changes to the city's governance, put his own henchmen in charge of city departments -- including Central Park. They cancelled the partially complete project in late 1870, and there the matter would have lain but in May 1871 someone ordered the gang of workmen to destroy all of its partly finished contents.

Professor Benton explains: "Previous accounts of the incident had always reported that this was done under the personal instruction of "Boss" Tweed himself, for various motives from raging that the display would be blasphemous, to vengeance for a perceived criticism of him in a New York Times report of the project's cancellation."

"Reading these reports, something didn't look right," Ms Coules said. "At the time Tweed was fighting for his political life, already accused of corruption and financial wrong-doings, so why was he so involved in a museum project?" She added, "So we went back to the original sources and found that it wasn't Tweed -- and the motive was not blasphemy or hurt vanity."

The situation was complicated by two other projects in development at the same time in Central Park, the American Museum of Natural History (AMNH) and the Central Park Zoo. But, as Professor Benton explained, "drawing on the detailed annual reports and minutes of Central Park, along with reports in the New York Times, we can show that the real villain was one strange character by the name of Henry Hilton."

Ms Coules adds: "Because all the primary sources are now available online, we could study them in detail -- and we could show that the destruction was ordered in a meeting by the real culprit, Henry Hilton, the Treasurer and VP of Central Park -- and it was carried out the day after this meeting."

Hilton was already notorious for other eccentric decisions. When he noticed a bronze statue in the Park, he ordered it painted white, and when a whale skeleton was donated to the American Museum of Natural History, he had that painted white as well. Later in life, other ill-judged decisions included cheating a widow out of her inheritance, squandering a huge fortune, and trashing businesses and livelihoods along the way.

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Colorado's spicy ancient history of chili peppers

Botanists and paleontologists, led by researchers from the University of Colorado Boulder, have identified a fossil chili pepper that may rewrite the geography and evolutionary timeline of the tomato plant family.

The team's findings, published last month in the journal New Phytologist, show that the chili pepper tribe (Capsiceae) within the tomato, or nightshade (Solanaceae), family is much older and was much more widespread than previously thought. Scientists previously believed that chili peppers evolved in South America at most 15 million years ago, but the new research pushes that date to at least 50 million years ago -- and suggests that chili peppers were in fact present in North America at that time.

Rocío Deanna, a postdoctoral researcher in ecology and evolutionary biology, and Abel Campos, an undergraduate double majoring in evolutionary biology and molecular, cellular and developmental biology, weren't planning to rewrite history when they met up one afternoon at the CU Boulder Museum of Natural History in 2021. Yet among a group of specimens in its collections gathered from the Green River Formation -- geological treasure trove in northwestern Colorado and southwestern Wyoming -- Deanna spotted a specific, solanaceous trait embedded in one fossil: little spikes on the end of a fruiting stem.

"At first, I thought 'No way! This can't be true,'" said Rocío Deanna, lead author of the study. "But it was so characteristic of the chili pepper."

After they discovered two of these fossils in the CU Boulder collections, Deanna and Campos, a co-author of the study, found one more from the chili pepper tribe in collections at the Denver Museum of Nature and Science. All three fossils are from the Green River Formation in Colorado: the CU specimens from Garfield County and the DMNS fossil from Rio Blanco County.

These chili pepper fossils from the Eocene geological epoch (34 to 56 million years ago) match the timeline of another nightshade fossil found in the Esmeraldas Formation in Colombia, revealing that the family was already distributed across all of the Americas by as early as 50 million years ago.

"The family is way older than we thought," said Deanna, also a faculty member at the National University of Cordoba.

A fruit-fossil history

The nightshade family comprises 3,000 species and almost 100 different genera, including chili peppers. The ancient chili pepper was technically a fruit -- and a berry, at that. While tomatoes and peppers are commonly associated with vegetables, they have seeds on the inside, which officially categorizes them as fruits.

The researchers cannot be sure of the chili's exact shape or color, but it was probably on the smaller end compared to modern day chili peppers. And like its relatives, it could have been quite spicy, according to Deanna.

Deanna and Campos identified the fossil by the unique shape of its calyx teeth: spikes on the end of the fruiting stem that hold on to the pepper, like those which hold a gemstone in a ring.

"The world has maybe 300,000 plant species. The only plants with that kind of calyx is this group of 80 or 90 species," said Stacey Smith, senior author of the paper and associate professor of evolutionary biology at CU Boulder.

Paleontologists collected the CU Boulder fossil from the Green River Formation in the 1990s. But its exact identity remained a mystery for years, in part because there are only a handful of "solanologists," botanists who study the nightshade family, in the world. When Deanna found these Colorado-based fossils, she had just returned from a global search for tomato family fossil specimens, only to find some "just ripe for the picking" right on campus.

"A lot of discoveries happen decades after the specimens have been collected," said Smith. "Who knows how many other new fossil species are sitting in any of these museums? They're just waiting for the right eyes to look at them."

Trickle-down evolution

These chili pepper fossils were around during the Eocene, a geologic epoch that lasted from about 34 to 56 million years ago as the continents drifted toward their present positions. During this balmy time in Earth's history, carbon dioxide levels ranged between 700 and 900 parts per million (twice as high as they are today), and palm trees grew as far north as Alaska. Because little to no ice was present on Earth, sea level was as much as 500 feet higher than it is today.

Scientists had assumed that the origins of chili peppers began in South America roughly 10 to 15 million years ago, where they then dispersed over land and water to the other continents. While Colorado today is home to very few native nightshades and no chili peppers, this new discovery hints that a plethora of plants from the tomato plant family may have existed in North America 40 to 50 million years ago, which have since largely disappeared.

But how did these peppers first get to North America? It's now a case of "the chicken or the chili pepper?"

Experts have theorized that fruit-eating birds, which existed as early as 60 million years ago, may have carried seeds and plants around the world with them in their guts, stuck to their feathers or in the mud on their feet. But these birds also had to be eating something to fuel their journeys -- and fleshy berries, or peppers, make the perfect fuel. Birds may have distributed peppers from continent to continent, but peppers may also have been crucial to the success of those same birds.

So the nightshade family could have easily started in North America instead of South America, then dispersed in the other direction -- and with this discovery, scientists can no longer say for sure, said Smith.

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Dinosaur claws used for digging and display

Dinosaur claws had many functions, but now a team from the University of Bristol and the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing has shown some predatory dinosaurs used their claws for digging or even for display.

The study focused on two groups of theropod dinosaurs, the alvarezsaurs and therizinosaurs, that had weird claws whose function had been a mystery up to now. It turns out that alvarezsaurs used their rock-pick-like claws for digging, but their close relatives, the giant therizinosaurs, used their overdeveloped, metre-long, sickle-like claws for display.

The new work is led by Zichuan Qin, a PhD student at the University of Bristol and the IVPP. He developed a new, computational approach in biomechanics to identify functions based on detailed comparison with living animals. First, the claws were modelled in three dimensions from CT scans, then modelled for stress and strain using engineering methods, and finally matched to functions of pulling, piercing and digging by comparison with modern animals whose claw functions are known.

"Alvarezsaurs and therizinosaurs are definitely the strangest cousins among dinosaurs," said Professor Michael Benton, one of Zichuan's supervisors. "Alvarezsaurs were the tiniest dinosaurs ever, the size of chickens, with stubby forelimbs and robust single claws, but their closest relative, the therizinosaurs, evolved in the exact opposite path."

"Therizinosaurus is famous for its sickle-like claws, each as long as a samurai sword: Edward Scissor-hands on speed. We all saw Therizinosaurus in 'Jurassic World' hitting deer and killing the giant predator Giganotosaurus. However, this is unlikely. These long, narrow claws were too weak for combat." said Dr Chun-Chi Liao, an expert on therizinosaurs from IVPP who co-authored this study. "Our engineering simulation shows that these claws could not withstand much stress."

"Not all therizinosaur hand claws were so useless in combat, but most other related species could use their claws as powerful hooking tools when feeding on leaves from the trees.," Dr Chun-Chi Liao added, "so, we conclude that the largest claws of any animal ever were actually useless in mechanical function, and so must have evolved under sexual selection to be used in display. The adult Therizinosaurus I guess could wave the claws at a competitor and effectively say, 'look at me, back off' or wave them around in some way like a peacock can use its tail in display to attract females for mating."

"Our previous work has shown that alvarezsaurs evolved to become the tiniest dinosaurs by the end of the Cretaceous, and these [dinosaurs] were using their punchy little claws for digging into ant hills and termite mounds. They were ant-eaters," said Zichuan Qin.

"Our study shows that the early alvarezsaurs, like Haplocheirus from the Jurassic, had multifunctional hands, but they were not good at digging. Their much smaller descendants had the efficient digging hands so they could feast on the Late Cretaceous termites." added Zichuan Qin.

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Researchers solve a 150-year-old mystery: Aetosaur find involves juveniles

Aetosaurs had a small head and a crocodile-like body. The land dwellers were up to six meters long and widely distributed geographically. They died out about 204 million years ago, at the end of the Triassic. In Kaltental near Stuttgart, Germany, an assemblage of 24 Aetosaurus ferratus individuals, only between 20 and 82 centimeters long, was discovered in 1877. Since then, scientists have been puzzling over whether they were juveniles or small adults. A team led by Elżbieta M. Teschner from the University of Bonn has now solved the mystery: Bone examination of two specimens shows that they are juveniles. The results have now been published in the Journal of Vertebrate Paleontology.

Reptiles of the genus Aetosaurus ferratus were discovered in a quarry near Kaltental, now a district of Stuttgart, and were first described nearly 150 years ago. The assemblage of about 24 individuals was dated to be about 215 million years old. "What was striking was that the total body length was only between 20 and 82 centimeters," says Elżbieta M. Teschner, who is pursuing a doctorate in paleontology at the University of Bonn while also conducting research at the University of Opole (Poland). "Interestingly, they were also the only fossils found in the area," she adds.

Oscar Fraas provided the first description of the skeletons in 1877 and suggested that they had washed up together. Sixteen years ago, Rainer R. Schoch of the State Natural History Museum in Stuttgart published a more detailed morphological study. Based on features visible to the naked eye, he determined that they must be juveniles. Together with Julia B. Desojo, an Argentine paleontologist from CONICET at the Museo de La Plata, they later described the skull of a larger skeleton of another aetosaur species (Paratypothorax andressorum). The find, more than 50 kilometers from Kaltental, could potentially be the adult form of the small aetosaur species known from the assemblage, they surmised.

Paleohistology enables age determination

The assumption only recently became certainty: With the help of the science of tissue growth (paleohistology) it has now become possible to examine the bones of the Kaltental find. "Long bones are a good model for calculating the age of animals because they deposit growth rings during their life that can be counted -- similar to the growth rings in tree trunks," says Dorota Konietzko-Meier, paleontologist from the University of Bonn. Based on this method, the relative individual age of the studied specimens could be determined.

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New geosciences study shows Triassic fossils that reveal origins of living amphibians

The smallest of newly found fossils can upend what paleontologists know about our history.

A team of paleontologists from Virginia Tech and the U.S. Petrified Forest National Park, among others, have discovered the first "unmistakable" Triassic-era caecilian fossil -- the oldest-known caecilian fossils -- thus extending the record of this small, burrowing animal by roughly 35 million years. The find also fills a gap of at least 87 million years in the known historical fossil record of the amphibian-like creature.

The fossil was first co-discovered by Ben Kligman, a doctoral student in the Department of Geosciences, part of the Virginia Tech College of Science, at Arizona's Petrified Forest National Park during a dig in 2019. Named by Kligman as Funcusvermis gilmorei, the fossil extends the history of caecilians 35 million years back to Triassic Period, roughly 250 million to 200 million years ago.

Prior to this new study, published today in the journal Nature, only 10 fossil caecilian occurrences were known, dating back to the Early Jurassic Period, about 183 million years ago. However, previous DNA studies estimated evolutionary origins of caecilians back to the Carboniferous or Permian eras, some 370 million to 270 million years ago, according to Kligman, marking that 87-million-year gap. However, no such fossils had been found.

"The discovery of the oldest caecilian fossils highlights the crucial nature of new fossil evidence. Many of the biggest outstanding questions in paleontology and evolution cannot be resolved without fossils like this," said Kligman, who previously discovered a 220-million-year-old species of cynodont or stem-mammal, a precursor of modern-day mammals. "Fossil caecilians are extraordinarily rare, and they are found accidentally when paleontologists are searching for the fossils of other more common animals. Our discovery of one was totally unexpected, and it transformed the trajectory of my scientific interests."

The discovery of the fossils was made in 2019 by Kligman and Petrified Forest National Park student intern Xavier Jenkins, now a Ph.D. student at Idaho State University, while the duo was processing fossiliferous sediment from the park's nicknamed Thunderstorm Ridge via a microscope. Funcusvermis was found in a layer of the Chinle Formation dated to approximately 220 million years ago, when Arizona was positioned near the equator at the central part of the supercontinent Pangaea, Kligman said. This region at the time was subject to a hot, humid climate. Today, Arizona is still hot, but has low humidity.

"Seeing the first jaw under the microscope, with its distinctive double row of teeth, sent chills down my back," Kligman said. "We immediately knew it was a caecilian, the oldest caecilian fossil ever found, and a once-in-a-lifetime discovery."

Previous to this find, the 87-million-year gap in the fossil record hid the early evolutionary history of caecilians, leading to a decades-long debate amongst scientists over the relationships of caecilians to their amphibian relatives, frogs and salamanders.

"Funcusvermis extends the humid equatorial pattern of occurrence seen in all known fossil and living caecilians, suggesting that the biogeographic history of caecilians has been guided by restriction to these ecological settings, likely due to physiological constraints linked to humidity, and constrained by the drift of continental plates into and out of the humid-equatorial zone after the fragmentation of Pangaea," Kligman said.

Modern caecilians are limbless amphibians with cylindrical bodies with a compact, bullet-shaped skull that helps them burrow underground. Now exclusively home to South and Central America, Africa, and southern Asia, caecilians spend their lives burrowing in leaf-litter or soil searching for prey such as worms and insects. This underground existence has made studying caecilians difficult for scientists. Kligman, tongue in cheek, describes modern caecilians as an "eyeless sock puppet with the body of a worm."

Funcusvermis actually shares skeletal features related more with early frog and salamander fossils, strengthening evidence for a shared origin and close evolutionary relationship between caecilians and these two groups. Funcusvermis also shares skeletal features with an ancient group of amphibians known to paleontologists as dissorophoid temnospondyls. Kligman adds, "Unlike living caecilians, Funcusvermis lacks many adaptations associated with burrowing underground, indicating a slower acquisition of features associated with an underground lifestyle in the early stages of caecilian evolution."

Name that tune

Now, here's the fun part: The genus name 'Funcusvermis' was inspired by the Ohio Players' 1972 song "Funky Worm" from their album Pleasure, a favorite song of the authors that was often played while excavating fossils at Thunderstorm Ridge. 'Funcus' is derived from the Latinized form of the English word Funky for the upbeat, rhythmic form of dance music, while 'vermis' is derived from the Latin word for worm. (It's an excellent song, by the way. Instant earworm, so to speak.)

The species name, gilmorei, honors Ned Gilmore, the collections manager at the Academy of Natural Sciences of Philadelphia's Drexel University. (Kligman is from Philadelphia and volunteered with Gilmore's herpetology wet collection as an undergraduate student. "He was an important mentor who helped inspire my interest in fossils and amphibians," Kligman said.)

Co-authors on the study include Michelle Stocker, an assistant professor, and Sterling Nesbitt, an associate professor, in the Virginia Tech Department of Geosciences and members of the Global Change Center that is part of the Fralin Life Sciences Institute. Other authors include Adam Marsh, lead paleontologist; Matthew Smith, museum curator; and William Parker, chief of science and resource management, all at the Petrified Forest National Park; and Bryan Gee, postdoctoral fellow at the University of Washington's Burke Museum and Department of Biology.

"As the eponymous song says, it's the funkiest worm in the world," Marsh quipped.

Stocker added, "What we collect really determines what we can say about which animals that were present, how many of them there were, and what they looked like. Without using these methods for fossil collection and analysis we would be missing out on knowing so many important aspects of this Triassic ecosystem. Now that we have a search image of what bones to look for and how to look for them, it will be exciting to see what other fossil localities preserve these early lissamphibians."

Nesbitt said finds such as this can reset the game board on paleontology, in the best sense of the phrase. "This find clearly demonstrates that some fossils that you can barely see can greatly change our understanding of entire groups that you can see today," he said.

What's happened since 2019

At the Petrified Forest National Park, where the initial discovery was found in 2019, the lower jaws of at least 70 individuals of Funcusvermis have been recovered as of summer 2022, making the area "the most abundant fossil caecilian-producing bonebed ever discovered," Kligman said.

Only a handful of bones of Funcusvermis have been found, including upper and lower jaws, a vertebra, and part of a hind-limb, Kligman said. All of the found bones were disarticulated, not as complete skeletons. Without complete skeletons, Kligman and his fellow researchers cannot exactly determine the body length of Funcusvermis, but inferences from isolated elements, such as the lower jaw being less than a quarter of an inch long, indicate that Funcusvermis was a tiny animal.

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Fossil CSI: Giant extinct marine reptile graveyard was likely ancient birthing grounds

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 Smithsonian Institution, Vanderbilt University, the Natural History Museum of Utah, the University of Utah, 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. Led by Neil Kelley, Vanderbilt University scientist and former Smithsonian's National Museum of Natural History Peter Buck postdoctoral fellow, and co-authored by the museum's curator of fossil marine mammals Nicholas Pyenson, 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.

"We present evidence that these ichthyosaurs died here in large numbers because they were migrating to this area to give birth for many generations across hundreds of thousands of years," Pyenson said. "That means this type of behavior we observe today in whales has been around for more than 200 million years."

Over the years, some paleontologists have proposed that BISP's ichthyosaurs -- predators resembling oversized chunky dolphins that have been adopted as Nevada's state fossil -- died in a mass stranding event such as those that sometimes afflicts modern whales, or that the creatures were poisoned by toxins from a nearby harmful algal bloom. The problem is that these hypotheses lack strong lines of scientific evidence to support them.

To try to solve this prehistoric mystery, the team combined newer paleontological techniques such as 3D scanning and geochemistry with traditional paleontological perseverance by poring over archival materials, photographs, maps, field notes and drawer after drawer of museum collections for shreds of evidence that could be reanalyzed.

Although most well-studied paleontological sites excavate fossils so they can be more closely studied by scientists at research institutions, the main attraction for visitors to the Nevada State Park-run BISP is a barn-like building that houses what researchers call Quarry 2, an array of ichthyosaurs that have been left embedded in the rock for the public to see and appreciate. Quarry 2 has partial skeletons from an estimated seven individual ichthyosaurs that all appear to have died around the same time.

"When I first visited the site in 2014, my first thought was that the best way to study it would be to create a full-color, high-resolution 3D model," Kelley said. "A 3D model would allow us to study the way these large fossils were arranged in relation to one another without losing the ability to go bone by bone."

To do this, Kelley, Pyenson and the research team collaborated with Jon Blundell, a member of the Smithsonian Digitization Program Office's 3D Program team, and Holly Little, a long-time collaborator with Pyenson and the 3D Program's team and currently the informatics manager in the museum's Department of Paleobiology. While Pyenson and Kelley were physically measuring bones and studying the site using traditional paleontological techniques, Little and Blundell used digital cameras and a spherical laser scanner to take hundreds of photographs and millions of point measurements that were then stitched together using specialized software to create a 3D model of the fossil bed.

To further home in on what might have befallen these extinct marine reptiles, the team collected tiny samples of the rock surrounding the fossils and performed a series of geochemical tests to look for signs of environmental disturbance.

One test measured mercury, which often accompanies large-scale volcanic activity, and found no significantly increased levels. Other tests examined different types of carbon and determined that there was no evidence of sudden increases in organic matter in the marine sediments that would result in a dearth of oxygen in the surrounding waters (though, like whales, the ichthyosaurs breathed air).

These geochemical tests revealed no signs that these ichthyosaurs perished because of some cataclysm that would have seriously disturbed the ecosystem in which they died. Kelley, Pyenson and other colleagues on the research team continued to look beyond Quarry 2 to the surrounding geology and all the fossils that had previously been excavated from the area.

The geologic evidence indicates that when the ichthyosaurs died, their bones eventually sank to the bottom of the sea, rather than along a shoreline shallow enough to suggest stranding, ruling out another hypothesis. Even more telling, though the area's limestone was chockfull of large adult Shonisaurus specimens, other marine vertebrates were scarce. The bulk of the other fossils at BISP come from small invertebrates such as clams and ammonites (spiral-shelled relatives of today's squid).

"There are so many large, adult skeletons from this one species at this site and almost nothing else," Pyenson said. "There are virtually no remains of things like fish or other marine reptiles for these ichthyosaursto feed on, and there are also no juvenile Shonisaurus skeletons."

The researchers' paleontological dragnet had eliminated some of the potential causes of death and started to provide intriguing clues about the type of ecosystem these marine predators were swimming in, but the evidence still did not clearly point to an alternative explanation.

The research team found a key piece of the puzzle when they discovered tiny ichthyosaur remains among new fossils collected at BISP and hiding within older museum collections. Careful comparison of the bones and teeth using micro-CT X-ray scans at Vanderbilt University revealed that these small bones were in fact embryonic and newborn Shonisaurus.

"Once it became clear that there was nothing for them to eat here, and there were large adult Shonisaurus along with embryos and newborns but no juveniles, we started to seriously consider whether this might have been a birthing ground," Kelley said.

Further analysis of the various strata in which the different clusters of ichthyosaur bones were found also revealed that the ages of the many fossil beds of BISP were separated by at least hundreds of thousands of years, if not millions.

"Finding these different spots with the same species spread across geologic time with the same demographic pattern tells us that this was a preferred habitat that these large oceangoing predators returned to for generations," Pyenson said. "This is a clear ecological signal, we argue, that this was a place that Shonisaurus used to give birth, very similar to today's whales. Now we have evidence that this sort of behavior is 230 million years old."

Kelley said the next step for this line of research is to investigate other ichthyosaur and Shonisaurus sites in North America with these new findings in mind to begin to recreate their ancient world -- perhaps by looking for other breeding sites or for places with greater diversity of other species that could have been rich feeding grounds for this extinct apex predator.

The 3D scans of the site are now available for other researchers to study and for the public to explore via the open-source Smithsonian's Voyager platform, which is developed and maintained by Blundell's team members at the Digitization Program Office. An interactive digital experience about the research team's study, including a 3D model of ichthyosaur sites analyzed, is also available on the Digitization Program Office's website.

"Our work is public," Blundell said. "We aren't just scanning sites and objects and locking them up. We create these scans to open up the collection to other researchers and members of the public who can't physically get to the Smithsonian."

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Dinosaur teeth reveal what they didn't eat

Scratches on dinosaur teeth could reveal what they really ate. For the first time, dental microwear texture analysis (DMTA) has been used to infer the feeding habits of large theropods, including Allosaurus and T. rex. By taking 3D images of individual teeth and analyzing the pattern of marks scratched into them, researchers could reason which dinosaurs may have frequently crunched on hard bone and which may have regularly eaten softer foods and prey. This technique opens up a new avenue of research for paleontology, helping us to better understand not only dinosaurs themselves but also the environment and communities in which they lived.

From Fantasia to Jurassic Park, the T. rex is seen as a terrifying apex predator that would chase down its prey and crunch on it whole. But how much did this iconic dinosaur actually chow down on bones? And what about other predatory dinosaurs that existed long before it?

Researchers from the University of Tokyo, in collaboration with teams from the University of Mainz and the University of Hamburg in Germany, have used dental microwear texture analysis (DMTA), a scanning technique to examine topographical dental wear and tear in microscopic detail, on individual dinosaur teeth from more than 100 million years ago to better understand what they may have eaten. "We wanted to test if we could use DMTA to find evidence of different feeding behaviors in tyrannosaurids (from the Cretaceous period, 145 million to 66 million years ago) compared to the older Allosaurus (from the Jurassic period, 201 million to 145 million years ago), which are both types of theropods," explained postdoctoral fellow Daniela Winkler from the Graduate School of Frontier Sciences. "From other research, we already knew that tyrannosaurids can crack and feed on bones (from studies of their feces and bite marks on bone). But allosaurs are much older and there is not so much information about them."

DMTA has mainly been used to study mammal teeth, so this is the first time it was used to study theropods. The same research team from the University of Tokyo also recently pioneered a study on DMTA in Japanese sauropod dinosaurs, famous for their long necks and tails. A high-resolution 3D image was taken of the tooth surface at a very small scale of 100 micrometers (one-tenth of a millimeter) by 100 micrometers in size. Up to 50 sets of surface texture parameters were then used to analyze the image, for example, the roughness, depth and complexity of wear marks. If the complexity was high, i.e., there were different-sized marks which overlaid each other, this was associated with hard object feeding, such as on bone. However, if the complexity was low, i.e., the marks were more arranged, of a similar size and not overlapping, this was associated with soft object feeding, like meat.

In total, the team studied 48 teeth, 34 from theropod dinosaurs and 14 from crocodilians (modern crocodiles and alligators), which were used as a comparison. The team was able to study original fossilized teeth and take high-resolution silicon molds, thanks to loans provided by natural history museums in Canada, the U.S., Argentina and Europe. "We actually started dental microwear research of dinosaurs in 2010," said Lecturer Mugino Kubo from the Graduate School of Frontier Sciences. "My husband, Dr. Tai Kubo, and I had started collecting dental molds of dinosaurs and their contemporaries in North and South Americas, Europe, and of course Asia. Since Daniela joined my lab, we utilized these molds to make a broader comparison among carnivorous dinosaurs."

"It was especially challenging to carry out this research during the pandemic," said Winkler "as we rely on being able to gather samples from international institutions. The sample size might not be so large this time, but it is a starting point."

Winkler says what they found surprising was that they didn't find evidence of much bone crushing behavior in either Allosaurus or tyrannosaurids, even though they know that tyrannosaurids ate bone. There may be several reasons for this unexpected outcome. It could be that although Tyrannosaurus was able to eat bone, it was less commonly done than previously thought. Also, the team had to use well-preserved teeth, so it might be that extremely damaged teeth that were excluded from this study were in such a condition because those animals fed more on bone.

Something the team did find with both the dinosaurs and crocodilians was a noticeable difference between juveniles and adults. "We studied two juvenile dinosaur specimens (one Allosaurus and one tyrannosaurid) and what we found was a very different feeding niche and behavior for both compared to the adults. We found that there was more wear to juvenile teeth, which might mean that they had to more frequently feed on carcasses because they were eating leftovers," explained Winkler. "We were also able to detect different feeding behavior in juvenile crocodilians; however, this time it was the opposite. Juvenile crocodilians had less wear on their teeth from eating softer foods, perhaps like insects, while adults had more dental wear from eating harder foods, like larger vertebrates."

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Mammoth problem with extinction timeline

Precisely 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 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 in 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.

"The issue is you have no idea how old that DNA is," Miller said. "Sedimentary deposits are complex. Materials of different ages are routinely buried together."

Researchers have many tools to date sedimentary deposits and the materials contained in them. But not everything can be dated, Miller said.

"We can radiocarbon date all kinds of things: bones, teeth, charcoal, leaves. That's very powerful. But currently we can't independently date DNA found in sediments," Miller said.

From recent discoveries like the baby mammoth found in Canada this year, we know that many ice age animals that died tens of thousands of years ago can become mummified in the arctic's dry, cold environment. Miller said researchers can't tell whether environmental DNA preserved in sediment was shed from a living or dead animal.

"DNA is shed from organisms all the time," Miller said. "In fact, DNA continues to be shed long after the animal dies. In places where decomposition is slow, that means long-dead and even long-extinct species can continue to make their way into surrounding sediments. In the arctic and other cold-weather places, it can take thousands of years for something to decompose."

The researchers say the slow decomposition of animals in arctic regions could explain how mammoth DNA is showing up thousands of years later than the most recent mammoth fossil discovered. The paper notes that the mummified remains of elephant seals near Antarctica can be more than 5,000 years old.

Simpson said his work studying marine environments from recently eroded hillsides demonstrates how difficult it is to date ancient specimens.

"Seashells can sit on the seafloor for thousands of years. When you see shells on the beach, some could be from animals that died recently while others might be from shellfish that died millennia ago," Simpson said. "This happens in the vertebrate record as well."

Miller said the question remains what impact, if any, humans had on the global decline and extinction of mammoths. Humans were known to use fire to alter landscapes in profound ways, Miller said. They also hunted mammoths and made use of their ivory tusks.

So when did the last mammoths die off? Scientists say most mammoths went extinct more than 10,000 years ago, but remnant populations lived on islands such as Russia's Wrangel Island until much more recently.

This cohabitation with modern humans is one reason mammoths capture our imaginations, researchers said.

"They're tantalizingly similar to animals that live among us today," Miller said. "We can almost touch them. That makes mammoths really alluring. For many people they are the poster children of ice age megafauna."

Simpson noted that mammoths once lived on the Channel Islands of California near where he grew up. The islands were home to a pygmy mammoth weighing 2,000 pounds. Today, the biggest mammal on the island is a tiny endemic fox.

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Fossil algae, dating from 541 million years ago, offer new insights into the plant kingdom's roots

Paleontologists have identified a new genus and species of algae called Protocodium sinense which predates the origin of land plants and modern animals and provides new insight into the early diversification of the plant kingdom.

Discovered at a site in China, this 541-million-year-old fossil is the first and oldest green alga from this era to be preserved in three dimensions, enabling the researchers to investigate its internal structure and identify the new specimen with unprecedented accuracy. The study is published today in BMC Biology, opening a window into a world of evolutionary puzzles that scientists are just beginning to unravel.

"Protocodium belongs to a known lineage of green algae and has a surprisingly modern architecture, showing that these algae were already well diversified before the end of the Ediacaran period," says co-author Cédric Aria, postdoctoral fellow in the Department of Ecology & Evolutionary Biology in the Faculty of Arts & Science at the University of Toronto and based at the Royal Ontario Museum (ROM). "Its discovery touches the origin of the entire plant kingdom and puts a familiar name on the organisms that preceded the Cambrian explosion over half a billion years ago, when the world's first modern ecosystems emerged."

The newly discovered Protocodium fossils were found by a team led by Hong Hua, professor of geology, and including Shu Chai, postdoctoral researcher, both of Northwest University, Xi'an, China. It is part of the Gaojiashan biota, the name given to a significant group of exceptionally well-preserved fossils, at the Dengying Formation in the southern Shaanxi Province. In the past 20 years, this geological formation has yielded important fossil species documenting the end of the Ediacaran Period 541-million-years ago.

Organisms and their parts that do not originally absorb minerals -- unlike shells or bones -- require exceptional conditions to be preserved. In this case, the whole fossils and their fine cellular details were preserved in three dimensions due to the replacement of the original organic material by phosphate. This mode of preservation allowed the researchers to use various electron and X-ray microscopy techniques to virtually slice the fossil, unveil its internal structure with precision and ultimately identify it as a close relative of the modern Codium alga, a type of seaweed.

Protocodium fossils are small spheres half a millimetre wide, like large grains of pollen, covered by a multitude of smaller domes. Thanks to the 3D examination, the researchers determined the domed surface to be part of a complex, single cell that contains thin strands called siphons. This morphology is typical of certain modern single-celled seaweeds that contain many nuclei.

The discovery of Protocodium would call for caution when identifying generic spherical Ediacaran fossils and may imply that organisms like Codium are in fact much older and widespread. The famous Doushantuo fossil embryos, also from China and preserved in 3D, have

been at the heart of debates about the deep origin of certain animal groups. Specific stages of some of these animal-like embryos resemble the unicellular Protocodium on the outside, but 3D slicing reveals how they are comprised of many cells. On the other hand, numerous 2D, round fossils of uncertain algal or other affinity are also known from the Ediacaran and older periods, but in less detail.

"We know that seaweed-like fossils are at least one billion-years-old," says Chai, the study's first author. "But until now, flat, grainy two-dimensional preservation has made it challenging to recognize more than general morphological structures."

Green algae are photosynthetic organisms, which means they convert light and carbon dioxide into sugars and oxygen. They were therefore likely important foundations of Earth's early ecosystems, and the study suggests green algae were already established in the world's shallow waters as carbon dioxide recyclers and oxygen producers before the Cambrian explosion.

Apart from its smaller size, Protocodium appears surprisingly identical to the modern Codium, a type of green algae found in many seas worldwide. Certain types of this seaweed are notoriously invasive -- such as Codium fragile subspecies tomentosoides, dubbed "dead man's fingers" for its appearance, and spread along with commercially farmed shellfish. From an evolutionary perspective, green algae like the ancient Protocodium and land plants share a common ancestor that was thought to be about one billion to one billion and a half years old, but now likely older -- the assignment of Protocodium so close to a modern group pushes back in time the history of the entire plant kingdom.

"It's very telling that such an organism has remained practically unchanged over at least 540 million years," says Aria. "By the Ediacaran, evolution had driven it towards a stable adaptive zone -- it's been comfortable there since, and more than that, quite successful. So much so, in fact, that nowadays Codium takes advantage of global trade to easily outcompete other algal species."

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