Coloured fossil snail shells (left) and a snail shell from modern times (large specimen on the right) Photo: Klaus Wolkenstein
Snail shells are often colourful and strikingly patterned. This is due to pigments that are produced in special cells of the snail and stored in the shell in varying concentrations. Fossil shells, on the other hand, are usually pale and inconspicuous because the pigments are very sensitive and have already decomposed. Residues of ancient colour patterns are therefore very rare. This makes this new discovery by researchers from the University of Göttingen and the Natural History Museum Vienna (NHMW) all the more astonishing: they found pigments in twelve-million-year-old fossilised snail shells. These are the world’s first pigments from the chemical group of polyenes that have been preserved almost unchanged and found in fossils. The study was published in the journal Palaeontology.
Palaeontologists from the NHMW found snail shells of the superfamily Cerithioidea in Burgenland, Austria.
The snails lived there twelve million years ago on the shores of a tropical sea.
Professor Mathias Harzhauser at NHMW, who was involved in the discovery, explains: “It was unclear whether the patterns of reddish colour were from the original shell or were formed by later processes in the sediment.” Researchers at Göttingen University’s Geoscience Center solved the mystery.
They analysed the pigments using Raman spectroscopy. This involves irradiating samples with laser light.
The scattered light reflected from the sample can be used to clearly identify chemical compounds.
They detected pigments in the fossilised shells that belong to the polyene group of chemicals.
These are organic compounds that include the well-known “carotenoids,” which are responsible for producing the vibrant red, orange and yellow colours seen in birds’ feathers, carrots and egg yolks, for instance.
Dr Klaus Wolkenstein, who led the study and has been researching the chemistry of fossil pigments at Göttingen University for many years, explains: “Normally, after such a long period of time, the best we can hope for is that there are traces of degradation products of these chemicals. If degraded, however, these compounds would be devoid of colour. So, it was really surprising to discover these pigments, preserved almost intact, in fossils that are twelve million years old.”
Reference:
Klaus Wolkenstein, Burkhard C. Schmidt, Mathias Harzhauser. Detection of intact polyene pigments in Miocene gastropod shells. Palaeontology, 2024; 67 (1) DOI: 10.1111/pala.12691
The modern Seattle fault zone cuts directly through the densely populated Puget lowlands, including Seattle and its metro area. Fifty million years ago, the continent tore in two here, setting the geologic stage for the modern faults, according to a new Tectonics study. Credit: Washington Geological Survey.
The Seattle fault zone is a network of shallow faults slicing through the lowlands of Puget Sound, threatening to create damaging earthquakes for the more than four million people who live there. A new origin story, proposed in a new study, could explain the fault system’s earliest history and help scientists improve hazard modeling for the densely populated region. The study was published in Tectonics, AGU’s journal for research exploring the evolution, structure and change of Earth’s crust and upper mantle.
The Seattle fault is active today because of forces exerted on the region from ongoing tectonic deformation both to the west and south, but that was not always the case. Washington in the Eocene looked different from today, with a coastline well east of where Seattle sits today and a chain of volcanic islands dotting the horizon offshore.
The study suggests that around 55 million years ago, that island chain was pulled toward the continent. As it ran into the North American plate, part of it went up and over the crust while the rest was sucked under it. Between these two parts, the crust would have been under great strain and torn. That ancient tear zone set the geologic stage for the modern Seattle fault, the study authors posit.
“It was a total surprise,” said Megan Anderson, a geophysicist with the Washington Geological Survey and lead author of the study. “It wasn’t something we were going for originally, but our results predict a major ancient fault where the Seattle fault is today.”
A massive mystery
The Pacific Northwest lies just inland from the Cascadia subduction zone, where dense oceanic crust gets pulled under the continent. In 1700, a roughly 1000-kilometer (620-mile) rupture of the subduction zone created a massive quake between magnitude 8.7 and 9.2; smaller quakes shook the region throughout the 1900s and, most recently, during the 2001 Nisqually earthquake. The Seattle fault ruptured notably in 923-924 AD, based on local Indigenous oral traditions and geologic evidence along the Puget Sound shoreline.
Despite the region’s seismic activity, scientists didn’t begin to study the Seattle fault zone in earnest until the 1990s.
“There’s a lot more uncertainty about the Seattle fault than, for example, the San Andreas fault,” Anderson said. “The Seattle fault could generate something like a magnitude 7.2 earthquake, and we want to be prepared for it. There’s still a lot to learn so that engineering geologists can do better simulations for earthquakes and understand the potential risks to our communities.”
Previous work to determine the geometry of the Seattle fault at depth relied primarily on seismic data, which are sound waves traveling through and being reflected by underground layers of rock. The data revealed faults and geologic structures that seismologists and geologists interpreted differently. They knew the region hosted a major fault zone, but scientists had proposed different ways parts of the fault are connected, how deep it extends, and how steeply it cuts through the bedrock.
Anderson and her co-authors set out to test the existing hypotheses of the fault zone’s geometry by mapping kilometers-deep bedrock across western Washington and building a more complete picture of the region’s geologic structure. Gravity and magnetic fields vary across Earth’s surface based on rocks’ density and composition, so Anderson compiled those data for western Washington and paired them with seismic data. The researchers also collected rock samples from geologic formations that correspond to different parts of the ancient fault and mountain system.
The researchers used computer models to see which, if any, of the hypotheses matched up with the gravity, magnetic and seismic data. The gravity data did not show a complex pattern, but the magnetic data revealed a key secret seismic data missed: deep in the crust, the bedrock consistently alternates between being more and less magnetic, suggesting slanted layers of changing rock type. And in map view, features on either side of the Seattle fault zone angle away from each other; north of the Seattle fault zone, structures are angled north-northwest, while in the south, they’re oriented north-northeast.
Those wonky orientations gave Anderson pause; they hinted at an ancient mountain range, but to check that, Anderson needed to match up the map-view data with deeper rocks. To connect the map view with known, deeper bedrock geology, Anderson modeled a vertical profile of rocks underground and found some of those structures dip at different orientations underground, too.
“These are all very different orientations,” Anderson said. “It’s very hard to do that unless there’s a place where the structures get disconnected from each other and then restart.”
Anderson had stumbled upon a new possible explanation for the Seattle fault zone’s early history and why it’s reactivated today.
A tear in the crustal continuum
The data suggested that about 55 million years ago, as the subduction zone pulled in a string of oceanic islands, the northern half of the island chain was subducted, but the southern half was added to the top of the crust, or obducted. Over a couple million years, as the islands were obducted, they crumpled into a fold-and-thrust mountain belt with topography similar to the Blue Ridge Mountains of Appalachia today.
The zone where the islands switched from being subducted to being accreted would have been under incredible strain and been ripped apart.
“It would have been this slow, ongoing tear, almost like the crust unzipping itself,” Anderson said. “As this progressed, the tear fault got longer and longer.”
And that “torn” region overlaps perfectly with the modern Seattle fault zone.
The intense tearing would have stopped after the islands were crunched into the continent, but the damage was done. The zone of intense tearing created fragmented, weakened crust, setting the geologic stage for the modern Seattle fault zone.
Beyond offering a possible explanation for why the fault zone exists, the study’s results about the geometry of Washington’s more ancient faults and geologic structures provide valuable details about the bedrock under and within the Seattle basin. This basin is filled with kilometers of looser sedimentary rock which make seismic ground shaking stronger, and the new data can help scientists make more accurate models of future ground shaking in the area.
Anderson is excited to use her findings to study western Washington’s active faults next.
“This buried tectonic story was so much fun to discover, and now it will provide a great basis for getting back to answering our original questions about active fault geometry for the Seattle fault and other faults in western Washington,” Anderson said.
Reference:
M. L. Anderson, R. J. Blakely, R. E. Wells, J. D. Dragovich. Deep Structure of Siletzia in the Puget Lowland: Imaging an Obducted Plateau and Accretionary Thrust Belt With Potential Fields. Tectonics, 2024 DOI: 10.1029/2022TC007720
Three types of granitoid rocks—tonalite, trondhjemite and granodiorite (TTG).
Geoscientists have uncovered a missing link in the enigmatic story of how the continents developed — a revised origin story that doesn’t require the start of plate tectonics or any external factor to explain their formation. Instead, the findings published last week in Nature Communications, rely solely on internal geological forces that occurred within oceanic plateaus that formed during the first few hundred million years of Earth’s history.
A major hurdle in understanding how the continents formed during the Archean Eon (four to 2.5 billion years ago) has been identifying the building blocks of Earth’s early crust.
Much of the “new” Archean crust formed during this period comprised a very distinct association of three types of granitoid rocks — tonalite, trondhjemite and granodiorite (TTG).
Understanding what went into making TTGs and the magmas they formed from has been difficult, because so many geological processes occurred between their initial melting and ultimate crystallization.
Earlier researchers focused on the trace element composition of these rocks, hoping to find clues about TTG magmas and their source.
“We tracked a specific set of trace elements that aren’t affected by alteration and pristinely preserve signatures from the original magma that made new TTG crust,” said Dr. Matthijs Smit, associate professor and Canada Research Chair at the University of British Columbia’s (UBC) Department of Earth, Ocean and Atmospheric Sciences.
“These elements allowed us to look back through the chemical changes that TTG magmas go through and trace the melt compositions back to their initial state and source — most likely a sort of gabbro.”
“Funnily enough, many people have varieties of this type of rock as a kitchen countertop,” Dr. Smit says.
“In a way, many people are preparing their dinner on the type of rock that was responsible for making our modern continents.”
The Archean TTG crust is still part of the continents today.
For instance, in North America they make up much of the Canadian Interior between the Cordillera mountain belt in the west and the Grenville and Appalachian mountain belts in the east.
The majority of Ontario, Quebec, Manitoba, Saskatchewan, Northwest Territories and Nunavut is made up of Archean crustal fragments that are dominated by TTGs and their slightly younger and more evolved granite counterparts.
“All of these rocks — and especially their combination — can be explained by the model we present,” said Dr. Smit.
“Ours is a simple model in which TTGs, as well as the younger rocks that TTGs are typically associated with, resulted from the slow burial, thickening and melting of precursor crust that likely resembled oceanic plateaus. The continental crust was destined to develop the way it did, because it kept getting buried further and the rocks at its base had no choice but to melt. In doing so, they made the TTGs that proved a winning recipe for continental survival and growth.”
The UBC researchers’ discovery of a stand-alone “intra-crustal” mechanism to make TTGs dispels the long-standing theory that Archean TTGs are formed in Earth’s first subduction zones and mark the start of plate tectonics.
“There’s always been a ‘chicken-and-egg’ question of which came first — the start of plate tectonics or TTG magmatism to make new continental crust,” says Dr. Smit.
“We show that these things may actually not be directly related. The recognition of the type of source rock makes this leap possible and also takes away the need to have other mechanisms, such as meteorite impact, explain the growth of the first real continents.”
The study by Dr. Smit and his UBC-based team used data from all the TTG samples ever analyzed — samples from Archean cratonic fragments exposed worldwide scrutinized by researchers over the past 30 years. This allowed Dr. Smit and his team to filter out local anomalies and analytical issues, and get at the actual trends in composition that the rocks capture. The study used a huge volume of data, now available in the open-source Geochemistry of Rocks of the Oceans and Continents geochemical data repository hosted by the Georg-August-Universität, Göttingen.
Reference:
Matthijs A. Smit, Kira A. Musiyachenko, Jeroen Goumans. Archaean continental crust formed from mafic cumulates. Nature Communications, 2024; 15 (1) DOI: 10.1038/s41467-024-44849-4
Shears — or breaks caused by strain — in rock outcrops like the one pictured here could shed new light on tectonics that occur between major earthquakes in the subduction zone, according to new research. A camera lens shows the scale of the features of the rock. Credit: Provided by Donald Fisher . All Rights Reserved.
Rocks once buried deep in ancient subduction zones — where tectonic plates collide — could help scientists make better predictions of how these zones behave during the years between major earthquakes, according to a research team from Penn State and Brown University.
Clues from rock formations in Alaska and Japan allowed the scientists to develop a new model to predict the pressure solution activity in subduction zones, the researchers reported in the journal Science Advances. Sedimentary rocks comprise grains surrounded by water-containing pores.
When rocks are squeezed together under great pressure, the grains dissolve at their boundaries into the water present in pores, forming pressure solution.
This allows the rocks to deform, or change shape, influencing how the tectonic plates slide past each other.
“It’s like when you go ice skating — the blade on the surface ends up melting the ice, which allows you to glide along,” said corresponding author Donald Fisher, professor of geosciences at Penn State.
“In rocks, what happens is quartz grains dissolve at stressed contacts and the dissolved material moves to cracks where it precipitates.”
The world’s most powerful earthquakes happen in subduction zones, where one tectonic plate slides beneath the other.
When these plates become stuck together, stress builds in the crust of the Earth — like a rubber band being stretched.
When enough stress builds up to overcome the friction holding the plates together — like a rubber band snapping — an earthquake occurs.
“We’ve shown that pressure solution is a fundamental process during the interseismic period in subduction zones,” Fisher said.
“The occurrence of this pressure solution can really affect the amount of elastic strain that accumulates in different parts of the seismogenic zone.”
Pressure solution is difficult to explore in the laboratory because it typically occurs very slowly over thousands to millions of years, Fisher said.
Speeding up the process in the lab requires higher temperatures, which produces other changes in rocks that impact the experiments.
The scientists instead turned to rocks that once experienced these tectonic pressures and were later brought to the surface by geological processes.
The rocks show microscopic shears — or breaks caused by strain — that contain textures that provide evidence for pressure solution, the scientists said.
“This work allows us to test a flow law, or model, that describes the rate of pressure solution in ancient rocks that were once down at the plate boundary and have been exhumed to the surface,” Fisher said.
“And we can apply this to active margins that are moving today.”
A previous study by another team of scientists linked stress the rocks experienced and strain rate — or how much they deformed.
In the new work, Fisher and his colleague, Greg Hirth, professor at Brown University, created a more detailed model that considers factors like the rocks’ grain size and solubility, or how much of the rock material can dissolve into liquid.
“We were able to parameterize the solubility as a function of temperature and pressure, in a practical way that hadn’t been done before,” Fisher said.
“So now we can plug in numbers — different grain sizes, different temperatures, different pressures and get the strain rate out of that.”
The results can help reveal where in the seismogenic layer — the range of depths at which most earthquakes occur — that strain is occurring.
The researchers applied their model to the Cascadia Subduction Zone, an active fault that runs from northern California to Canada and by major cities like Portland, Oregon, Seattle and Vancouver, British Columbia.
The temperature along the plate boundary and the amount of strain built up is well studied there, and the results of their model match crustal movements based on satellite observations, the scientists said.
“Cascadia is a great example because it’s late in the interseismic period — it’s been 300 years since the last major earthquake,” Fisher said.
“We may experience one in our lifetime, which would be the biggest natural disaster that North America can anticipate in terms of the potential for shaking and resulting tsunami.”
The National Science Foundation supported this work.
Reference:
Donald M. Fisher, Greg Hirth. A pressure solution flow law for the seismogenic zone: Application to Cascadia. Science Advances, 2024; 10 (4) DOI: 10.1126/sciadv.adi7279
Note: The above post is reprinted from materials provided by Penn State. Original written by Matthew Carroll.
Sanfordiacaulis densifolia fossil (Scale is 1 m). Credit: Matthew Stimson
In the fossil record, trees typically are preserved with only their trunks. They don’t usually include any leaves to show what their canopies and overall forms may have looked like. But now, researchers reporting in the journal Current Biology on February 2 describe fossilized trees from New Brunswick, Canada with a surprising and unique three-dimensional crown shape.
“The way in which this tree produced hugely long leaves around its spindly trunk, and the sheer number over a short length of trunk, is startling,” says Robert Gastaldo of Colby College in Waterville, Maine.
The forms taken by these 350-million-year-old trees look something like a fern or palm, even though palms didn’t arise until 300 million years later, he explains.
However, the functional leaves in ferns or palm trees cluster at the top and are relatively few.
“In contrast, Sanfordiacaulis preserves more than 250 leavesaround its trunk, with each partially preserved leaf extending 1.75 meters from it,” Gastaldo says.
“We estimate that each leaf grew at least another meter before terminating. This means that the ‘bottle brush’ had a dense canopy of leaves that extended at least 5.5 meters (or 18 feet) around a trunk that was non-woody and only 16 centimeters (or 0.5 feet) in diameter. Startling to say the least.”
This work was made possible by a long-term international collaboration with Matthew Stimson and Olivia King of the New Brunswick Museum, Saint John, and Saint Mary’s University in Halifax.
The researchers’ findings offer important insights into the evolution of plants and arborescence, meaning plants that grow to a tree height, or at least 15 feet at maturity.
They’re also a reminder that over the history of life on Earth, there have existed trees that look unlike any we’ve ever seen before and some that look as though they may come from the imagination of Dr. Seuss, the researchers say.
“We all have a mental concept of what a tree looks like, depending on where we live on the planet, and we have a vision of what is familiar,” Gastaldo says.
The fossils in question were preserved by earthquake-induced, catastrophic burial of trees and other vegetation along the margin of a rift lake.
The first fossil tree was unearthed about 7 years ago from a quarry, but it only included one partial sample.
It took several years for another four specimens of the same plant, in close spatial proximity, to also be found, Gastaldo says.
One of the specimens revealed how the leaves departed from the top of the tree, which makes it “absolutely unique.” It’s one of only a few in a fossil record spanning more than 400 million years in which a trunk is preserved around which the crown leaves are still attached, the researchers say.
“Any fossil tree with an intact crown is a rarity in the history of life,” Gastaldo says.
“Having the crown leaves attached to a trunk, by itself, begs the questions what kind of plant is it, how is that plant organized, And is it some form that continues to the present, or is it outside of the ‘normal’ concept of a tree? All of these questions, and more, led to this multi-year endeavor.”
The researchers report that the tree likely relied on its unusual growth form to maximize the amount of light it could capture and reduce its competition with other plants on the ground.
They suggest that the tree now represents the earliest evidence of smaller trees growing beneath a taller forest canopy.
It means that plant life in the Early Carboniferous period was more complex than expected, suggesting Sanfordiacaulis lived at a time when plants were “experimenting” with a variety of possible forms or architectures.
“The history of life on land consists of plants and animals that are unlike any of those that live at the present,” Gastaldo says. “Evolutionary mechanisms operating in the deep past resulted in organisms that successfully lived over long periods of time, but their shapes, forms, growth architectures, and life histories undertook different trajectories and strategies. Rare and unusual fossils, such as the New Brunswick tree, is but one example of what colonized our planet but was an unsuccessful experiment.”
Reference:
Robert A. Gastaldo, Patricia G. Gensel, Ian J. Glasspool, Steven J. Hinds, Olivia A. King, Duncan McLean, Adrian F. Park, Matthew R. Stimson, Timothy Stonesifer. Enigmatic fossil plants with three-dimensional, arborescent-growth architecture from the earliest Carboniferous of New Brunswick, Canada. Current Biology, 2024; DOI: 10.1016/j.cub.2024.01.011
Note: The above post is reprinted from materials provided by Cell Press.
Showing partial skeleton of gliding reptile Kuehneosaurus on rock from Emborough. Image credit: David Whiteside
Gliding winged-reptiles were amongst the ancient crocodile residents of the Mendip Hills in Somerset, researchers at the University of Bristol have revealed.
Kuehneosaurs looked like lizards, but were more closely related to the ancestors of crocodilians and dinosaurs.
They were small animals, which could fit neatly on the palm of a hand, and there were two species, one with extensive wings, the other with shorter wings, made from a layer of skin stretched over their elongated side ribs, which allowed them to swoop from tree to tree.
Like the modern flying lizard Draco from southeast Asia, they most likely wandered about on the ground and climbed trees in search of insect prey.
When startled, or if they spotted a tasty insect flying by, they could launch themselves into the air, and land safely 10m away.
The discovery was made by University of Bristol Masters student Mike Cawthorne, researching numerous reptile fossils from limestone quarries, which formed the biggest sub-tropical island at the time, called the Mendip Palaeo-island.
The study, published today in Proceedings of the Geologists’ Association, also records the presence of reptiles with complex teeth, the trilophosaur Variodens and the aquatic Pachystropheus that probably lived a bit like a modern-day otter likely eating shrimps and small fish.
The animals either fell or their bones were washed into caves and cracks in the limestone.
“All the beasts were small,” said Mike.
“The collections I studied had been made in the 1940s and 1950s when the quarries were still active, and palaeontologists were able to visit and see fresh rock faces and speak to the quarrymen.”
Professor Mike Benton Bristol’s School of Earth Sciences explained: “It took a lot of work identifying the fossil bones, most of which were separate and not in a skeleton.
“However, we have a lot of comparative material, and Mike Cawthorne was able to compare the isolated jaws and other bones with more complete specimens from the other sites around Bristol.
“He has shown that the Mendip Palaeo-island, which extended from Frome in the east to Weston-super-Mare in the west, nearly 30 km long, was home to diverse small reptiles feeding on the plants and insects.
“He didn’t find any dinosaur bones, but it’s likely that they were there because we have found dinosaur bones in other locations of the same geological age around Bristol.”
The area around Bristol 200 million years ago in the Late Triassic was an archipelago of small islands set in a warm sub-tropical sea.
Bristol’s Dr David Whiteside added: “The bones were collected by some great fossil finders in the 1940s and 1950s including Tom Fry, an amateur collector working for Bristol University and who generally cycled to the quarries and returned laden with heavy bags of rocks.
“The other collectors were the gifted researchers Walter Kühne, a German who was imprisoned in Great Britain in the 2nd world war, and Pamela L. Robinson from University College London. They gave their specimens to the Natural History Museum in London and the Geological collections of the University of Bristol.”
Reference:
Michael Cawthorne, David I. Whiteside, Michael J. Benton. Latest Triassic terrestrial microvertebrate assemblages from caves on the Mendip palaeoisland, S.W. England, at Emborough, Batscombe and Highcroft Quarries. Proceedings of the Geologists’ Association, 2024; DOI: 10.1016/j.pgeola.2023.12.003
Study sheds new light on the body form of the Megalodon, and its role in shaping ancient marine life. (DePaul University/Kenshu Shimada)
A new study shows the Megalodon, a gigantic shark that went extinct 3.6 million years ago, was more slender than earlier studies suggested. This finding changes scientists’ understanding of Megalodon behavior, ancient ocean life, and why the sharks went extinct.
The Megalodon or megatooth shark is typically portrayed as a super-sized monster in popular culture, with recent examples in the sci-fi films “The Meg” (2018) and “Meg 2: The Trench” (2023). Previous studies assume that the shark likely reached lengths of at least 50 feet and possibly as much as 65 feet.
However, the Megalodon is largely known only from its teeth and vertebrae in the fossil record — a rather incomplete set of data from which to draw assumptions.
Thus, the modern great white shark was traditionally used as a model for Megalodon bodies in previous studies.
That model led researchers to conclude that the shark was round and stocky like great whites.
“Our team reexamined the fossil record, and discovered the Megalodon was more slender and possibly even longer than we thought. Therefore, a better model might be the modern mako shark,” said UCR biologist and paper first author Phillip Sternes.
“It still would have been a formidable predator at the top of the ancient marine food chain, but it would have behaved differently based on this new understanding of its body.”
For the new study published in the journal Palaeontologia Electronica, a team of 26 scientists from around the world, co-led by Sternes and DePaul University paleobiology professor Kenshu Shimada, was inspired by differences in previously estimated body lengths for the Megalodon.
“It was a ‘eureka-moment’ when our research team realized the discrepancy between two previously published lengths for the same Megalodon specimen,” said Shimada.
The team then weighed in on a new comparison of Megalodon vertebra fossils to those of living lamniform shark relatives.
“We measured the whole vertebral skeleton of a living great white shark with a CT scanner and compared that to the previous reconstruction of the Megalodon vertebral column,” Sternes said.
“It was still a giant, predatory shark. But the results strongly suggest that the Megalodon was not merely a larger version of the modern great white shark.”
A revised understanding of the Megalodon body type would in turn affect scientists’ understanding not only of the giant shark itself, but also of its impact on the ecology and evolution of marine ecosystems that shaped the present-day oceans.
There is no doubt the Megalodon is one of the largest marine predators ever to have lived.
But a slimmer and more elongated body would suggest the Megalodon also had a longer digestive canal.
Sternes explained that in this case, the sharks might have enjoyed enhanced absorption of nutrients, and may not have had to eat as often as previously believed.
“With increased ability to digest its food, it could have gone for longer without needing to hunt. This means less predation pressure on other marine creatures,” Sternes said.
“If I only have to eat one whale every so often, whale populations would remain more stable over time.”
Some shark scientists have theorized that a natural decrease in prey led to the extinction of Megalodons.
However, Sternes has another theory, in part supported by the revised understanding of its shape.
“I believe there were a combination of factors that led to the extinction, but one of them may have been the emergence of the great white shark, which was possibly more agile, making it an even better predator than the Megalodon,” Sternes said.
“That competition for food may have been a major factor in its demise.”
The research team of shark experts from the U.S., UK, Austria, France, Japan, Mexico, Brazil, and Australia all feel that a revised understanding of ancient marine life would have a cascading effect on the oceans that are still visible today.
“Now that we know it was a thinner shark, we need to reinvestigate its lifestyle, how it really lived, and what caused it to die,” Sternes said. “This study represents a major stepping stone for others to follow up on.”
Reference:
Phillip C. Sternes, Patrick L. Jambura, Julia Türtscher, Jürgen Kriwet, Mikael Siversson, Iris Feichtinger, Gavin J.P. Naylor, Adam P. Summers, John G. Maisey, Taketeru Tomita, Joshua K. Moyer, Timothy E. Higham, João Paulo C.B. da Silva, Hugo Bornatowski, Douglas J. Long, Victor J. Perez, Alberto Collareta, Charlie Underwood, David J. Ward, Romain Vullo, Gerardo González-Barba, Harry M. Maisch IV, Michael L. Griffiths, Martin A. Becker, Jake J. Wood, and Kenshu Shimada. White shark comparison reveals a slender body for the extinct megatooth shark, Otodus megalodon (Lamniformes: Otodontidae). Palaeontologia Electronica, 2024 DOI: 10.26879/1345
Researchers have linked the travels of a 14,000-year-old woolly mammoth with the oldest known human settlements in Alaska, providing clues about the relationship between the iconic species and some of the earliest people to travel across the Bering Land Bridge.
Scientists made those connections by using isotope analysis to study the life of a female mammoth, named Élmayųujey’eh, by the Healy Lake Village Council.
A tusk from Elma was discovered at the Swan Point archaeological site in Interior Alaska.
Samples from the tusk revealed details about Elma and the roughly 1,000-kilometer journey she took through Alaska and northwestern Canada during her lifetime.
Isotopic data, along with DNA from other mammoths at the site and archaeological evidence, indicates that early Alaskans likely structured their settlements to overlap with areas where mammoths congregated.
Those findings, highlighted in the new issue of the journal Science Advances, provide evidence that mammoths and early hunter-gatherers shared habitat in the region.
The long-term predictable presence of woolly mammoths would have attracted humans to the area.
“She wandered around the densest region of archaeological sites in Alaska,” said Audrey Rowe, a University of Alaska Fairbanks Ph.D. student and lead author of the paper.
“It looks like these early people were establishing hunting camps in areas that were frequented by mammoths.”
The mammoth tusk was excavated and identified in 2009 by Charles Holmes, affiliate research professor of anthropology at UAF, and François Lanoë, research associate in archaeology at the University of Alaska Museum of the North.
They found Elma’s tusk and the remains of two related juvenile mammoths, along with evidence of campfires, the use of stone tools, and butchered remains of other game.
All of this “indicates a pattern consistent with human hunting of mammoths,” said Ben Potter, an archaeologist and professor of anthropology at UAF.
Researchers at UAF’s Alaska Stable Isotope Facility then analyzed thousands of samples from Elma’s tusk to recreate her life and travels.
Isotopes provide chemical markers of an animal’s diet and location.
The markers are then recorded in the bones and tissues of animals and remain even after they die.
Mammoth tusks are well-suited to isotopic study because they grew throughout the ancient animals’ lives, with clearly visible layers appearing when split lengthwise.
Those growth bands give researchers a way to collect a chronological record of a mammoth’s life by studying isotopes in samples along the tusk.
Much of Elma’s journey overlapped with that of a previously studied male mammoth who lived 3,000 years earlier, demonstrating long-term movement patterns by mammoths over several millennia.
In Elma’s case, they also indicated she was a healthy 20-year-old female.
“She was a young adult in the prime of life. Her isotopes showed she was not malnourished and that she died in the same season as the seasonal hunting camp at Swan Point where her tusk was found,” said senior author Matthew Wooller, who is director of the Alaska Stable Isotope Facility and a professor at UAF’s College of Fisheries and Ocean Sciences.
The era in which Elma lived may have compounded the challenges posed by the relatively recent appearance of humans.
The grass- and shrub-dominated steppe landscape that had been common in Interior Alaska was beginning to shift toward more forested terrain.
“Climate change at the end of the ice age fragmented mammoths’ preferred open habitat, potentially decreasing movement and making them more vulnerable to human predation,” Potter said.
Other contributors to the study included the University of Alaska Anchorage, University of Ottawa, McMaster University, University of Alaska Museum of the North, University of Michigan Museum of Paleontology, Adelphi University, University of Arizona, Hakai Institute and the Healy Lake Village Council.
Reference:
Audrey G. Rowe, Clement P. Bataille, Sina Baleka, Evelynn A. Combs, Barbara A. Crass, Daniel C. Fisher, Sambit Ghosh, Charles E. Holmes, Kathryn E. Krasinski, François Lanoë, Tyler J. Murchie, Hendrik Poinar, Ben Potter, Jeffrey T. Rasic, Joshua Reuther, Gerad M. Smith, Karen J. Spaleta, Brian T. Wygal, Matthew J. Wooller. A female woolly mammoth’s lifetime movements end in an ancient Alaskan hunter-gatherer camp. Science Advances, 2024; 10 (3) DOI: 10.1126/sciadv.adk0818
Curtin-led research has for the first time precisely dated some of the oldest fossils of complex multicellular life in the world, helping to track a pivotal moment in the history of Earth when the seas began teeming with new lifeforms — after four billion years of containing only single-celled microbes.
Lead author PhD student Anthony Clarke, from the Timescales of Mineral Systems Group within Curtin’s School of Earth and Planetary Sciences, said to determine the age of the fossils, researchers used volcanic ash layers like bookmarks in the geological sequence.
“Located in the Coed Cochion Quarry in Wales, which contains the richest occurrence of shallow marine life in Britain, we used outfall from an ancient volcano that blanketed the animals as a time marker to accurately date the fossils to 565 million years, accurate down to 0.1 per cent,” Mr Clarke said.
“With similar Ediacaran fossils found at sites around the world including in Australia, dating the fossils identifies them as being part of an ancient living community that developed as Earth thawed out from a global ice age.
“These creatures would in some ways resemble modern day marine species such as jellyfish, yet in other ways be bizarre and unfamiliar. Some appear fern-like, others like cabbages, whereas others resembled sea pens.”
Study co-author Professor Chris Kirkland, also from the Timescales of Mineral Systems Group at Curtin, said the fossils are named after the Ediacara Hills in South Australia’s Flinders Ranges, where they were first discovered, leading to the first new geological period established in over a century.
“These Welsh fossils appear directly comparable to the famous fossils of Ediacara in South Australia,” Professor Kirkland said.
“The fossils, including creatures like the disc-shaped Aspidella terranovica, showcase some of the earliest evidence of large-scale multicellular organisms, marking a transformative moment in Earth’s biological history.
“Ediacaran fossils record the response of life to the thaw out from a global glaciation, which shows the deep connection between geological processes and biology.
“Our study underscores the importance of understanding these ancient ecosystems in order to unravel the mysteries of Earth’s past and shape our comprehension of life’s evolution.”
Reference:
Anthony J. I. Clarke, Christopher L. Kirkland, Latha R. Menon, Daniel J. Condon, John C. W. Cope, Richard E. Bevins, Stijn Glorie. U–Pb zircon–rutile dating of the Llangynog Inlier, Wales: constraints on an Ediacaran shallow-marine fossil assemblage from East Avalonia. Journal of the Geological Society, 2024; 181 (1) DOI: 10.1144/jgs2023-081
Note: The above post is reprinted from materials provided by Curtin University. Original written by Lucien Wilkinson.
For decades, paleontologists have debated whether Nanotyrannus is a separate species or simply a juvenile T. rex. (Credit Raul Martin)
A new analysis of fossils believed to be juveniles of T. rex now shows they were adults of a small tyrannosaur, with narrower jaws, longer legs, and bigger arms than T. rex. The species, Nanotyrannus lancensis, was first named decades ago but later reinterpreted as a young T. rex.
The first skull of Nanotyrannus was found in Montana in 1942, but for decades, paleontologists have gone back and forth on whether it was a separate species, or simply a juvenile of the much larger T. rex.
Dr Nick Longrich, from the Milner Centre for Evolution at the University of Bath (UK), and Dr Evan Saitta, from the University of Chicago (USA) re-analysed the fossils, looking at growth rings, the anatomy of Nanotyrannus, and a previously unrecognized fossil of a young T. rex.
Measuring the growth rings in Nanotyrannus bones, they showed that they became more closely packed towards the outside of the bone — its growth was slowing. It suggests these animals were nearly full size; not fast-growing juveniles.
Modelling the growth of the fossils showed the animals would have reached a maximum of around 900-1500 kilograms and five metres — about 15 per cent of the size of the giant T. rex, which grew to 8,000 kilograms and nine metres or more.
The researchers have published their findings in Fossil Studies.
“When I saw these results I was pretty blown away,” said Longrich. “I didn’t expect it to be quite so conclusive.
“If they were young T. rex they should be growing like crazy, putting on hundreds of kilograms a year, but we’re not seeing that.
“We tried modeling the data in a lot of different ways and we kept getting low growth rates. This is looking like the end for the hypothesis that these animals are young T. rex.”
Supporting the existence of distinct species, the researchers found no evidence of fossils combining features of both the Nanotyrannus and T. rex – which would exist if the one turned into the other. Every fossil they examined could be confidently identified as one species or the other.
Neither did the patterns of growth in other tyrannosaurs fit with the hypothesis that these were young T. rex.
Dr Longrich said: “If you look at juveniles of other tyrannosaurs, they show many of the distinctive features of the adults. A very young Tarbosaurus – a close relative of T. rex – shows distinctive features of the adults.
“In the same way that kittens look like cats and puppies look like dogs, the juveniles of different tyrannosaurs are distinctive. And Nanotyrannus just doesn’t look anything like a T. rex.
“It could be growing in a way that’s completely unlike any other tyrannosaur, or any other dinosaur- but it’s more likely it’s just not a T. rex.”
But that raises a mystery — if Nanotyrannus isn’t a juvenile Tyrannosaurus, then why hasn’t anyone ever found a young T. rex?
“That’s always been one of the big questions. Well, it turns out we actually had found one,” said Longrich. “But the fossil was collected years ago, stuck in a box of unidentified bones in a museum drawer, and then forgotten.”
The research led Longrich and co-author Evan Saitta to a previous fossil discovery, stored in a museum in San Francisco which they identified as a juvenile Tyrannosaurus.
That young T. rex is represented by a skull bone — the frontal bone — with distinctive features that ally it with Tyrannosaurus, but which aren’t seen in Nanotyrannus. It comes from a small animal, one with a skull about 45 cm long and a body length of around 5 metres.
Dr Longrich said: “Yes, it’s just one specimen, and just one bone, but it only takes one. T. rex skull bones are very distinctive, nothing else looks like it. Young T. rex exist, they’re just incredibly rare, like juveniles of most dinosaurs.”
The researchers argue these findings are strong evidence that Nanotyrannus is a separate species, one not closely related to Tyrannosaurus. It was more lightly-built and long-limbed than its thick-set relative. It also had larger arms, unlike the famously short-armed T. rex.
“The arms are actually longer than those of T. rex. Even the biggest T. rex, has shorter arms and smaller claws than in these little Nanotyrannus. This was an animal where the arms were actually pretty formidable weapons. It’s really just a completely different animal — small, fast, agile.
“T. rex relied on size and strength, but this animal relied on speed.”
The long arms and other features suggest it was only distantly related to T. rex – and may have sat outside the family Tyrannosauridae, which T. rex is part of, in its own family of predatory dinosaurs.
The new study is the latest in a series of publications on the problem, going back decades.
Longrich said: “Nanotyrannus is highly controversial in paleontology. Not long ago, it seemed like we’d finally settled this problem, and it was a young T. rex.
“I was very skeptical about Nanotyrannus myself until about six years ago when I took a close look at the fossils and was surprised to realise we’d gotten it wrong all these years.”
The authors suggest that, given how difficult it is to tell dinosaurs apart based on their often-incomplete skeletons, we may be underestimating the diversity of dinosaurs, and other fossil species.
Longrich said: “It’s amazing to think how much we still don’t know about the most famous of all the dinosaurs. It makes you wonder what else we’ve gotten wrong.”
Reference:
Nicholas R. Longrich, Evan T. Saitta. Taxonomic Status of Nanotyrannus lancensis (Dinosauria: Tyrannosauroidea)—A Distinct Taxon of Small-Bodied Tyrannosaur. Fossil Studies, 2024; 2 (1): 1 DOI: 10.3390/fossils2010001
A mosasaur discovered in Japan was the most complete skeleton ever found in Japan or the northwestern Pacific. Graphic/Takuya Konishi
Researchers have described a Japanese mosasaur the size of a great white shark that terrorized Pacific seas 72 million years ago.
Extra-long rear flippers might have aided propulsion in concert with its long finned tail.
And unlike other mosasaurs, or large extinct marine reptiles, it had a dorsal fin like a shark’s that would have helped it turn quickly and with precision in the water.
University of Cincinnati Associate Professor Takuya Konishi and his international co-authors described the mosasaur and placed it in a taxonomic context in the Journal of Systematic Palaeontology.
The mosasaur was named for the place where it was found, Wakayama Prefecture.
Researchers call it the Wakayama Soryu, which means blue dragon.
Dragons are creatures of legend in Japanese folklore, Konishi said.
“In China, dragons make thunder and live in the sky. They became aquatic in Japanese mythology,” he said.
The specimen was discovered along the Aridagawa River in Wakayama by co-author Akihiro Misaki in 2006.
The specimen is the most complete skeleton of a mosasaur ever found in Japan or the northwestern Pacific, Konishi said.
“In this case, it was nearly the entire specimen, which was astounding,” Konishi said.
He has dedicated his career to studying these ancient marine reptiles.
But the Japanese specimen has unique features that defies simple classification, he said.
Its rear flippers are longer than its front ones. These enormous flippers are even longer than its crocodile-like head, which is unique among mosasaurs.
“I thought I knew them quite well by now,” Konishi said. “Immediately it was something I had never seen before.”
Mosasaurs were apex predators in prehistoric oceans from about 100 million years ago to 66 million years ago.
They were contemporaries of Tyrannosaurus rex and other late Cretaceous dinosaurs that ruled the Earth.
Mosasaurs were victims of the same mass extinction that killed off nearly all dinosaurs when an asteroid struck what is now the Gulf of Mexico.
Researchers placed the specimen in the subfamily Mosasaurinae and named it Megapterygius wakayamaensis to recognize where it was found.
Megapterygius means “large winged” in keeping with the mosasaur’s enormous flippers.
Konishi said those big paddle-shaped flippers might have been used for locomotion.
But that type of swimming would be extraordinary not only among mosasaurs but among virtually all other animals.
“We lack any modern analog that has this kind of body morphology — from fish to penguins to sea turtles,” he said.
“None has four large flippers they use in conjunction with a tail fin.”
Researchers speculated that the large front fins might have helped with rapid maneuvering while its large rear fins might have provided pitch to dive or surface.
And presumably like other mosasaurs, its tail would have generated powerful and fast acceleration as it hunted fish.
“It opens a whole can of worms that challenges our understanding of how mosasaurs swim,” Konishi said.
Reference:
Takuya Konishi, Masaaki Ohara, Akihiro Misaki, Hiroshige Matsuoka, Hallie P. Street, Michael W. Caldwell. A new derived mosasaurine (Squamata: Mosasaurinae) from south-western Japan reveals unexpected postcranial diversity among hydropedal mosasaurs. Journal of Systematic Palaeontology, 2023; 21 (1) DOI: 10.1080/14772019.2023.2277921
What wiped out the dinosaurs? A meteorite plummeting to Earth is only part of the story, a new study suggests. Climate change triggered by massive volcanic eruptions may have ultimately set the stage for the dinosaur extinction, challenging the traditional narrative that a meteorite alone delivered the final blow to the ancient giants.
That’s according to a study published in Science Advances, co-authored by Don Baker, a professor in McGill University’s Department of Earth and Planetary Sciences.
The research team delved into volcanic eruptions of the Deccan Traps — a vast and rugged plateau in Western India formed by molten lava.
Erupting a staggering one million cubic kilometres of rock, it may have played a key role in cooling the global climate around 65 million years ago.
The work took researchers around the world, from hammering out rocks in the Deccan Traps to analyzing the samples in England and Sweden.
A new season?: ‘Volcanic winters’
In the lab, the scientists estimated how much sulfur and fluorine was injected into the atmosphere by massive volcanic eruptions in the 200,000 years before the dinosaur extinction.
Remarkably, they found the sulfur release could have triggered a global drop in temperature around the world — a phenomenon known as a volcanic winter.
“Our research demonstrates that climatic conditions were almost certainly unstable, with repeated volcanic winters that could have lasted decades, prior to the extinction of the dinosaurs. This instability would have made life difficult for all plants and animals and set the stage for the dinosaur extinction event. Thus our work helps explain this significant extinction event that led to the rise of mammals and the evolution of our species,” said Prof.
Don Baker.
New technique
Uncovering clues within ancient rock samples was no small feat.
In fact, a new technique developed at McGill helped decode the volcanic history.
The technique for estimating sulfur and fluorine releases-a complex combination of chemistry and experiments-is a bit like cooking pasta.
“Imagine making pasta at home. You boil the water, add salt, and then the pasta. Some of the salt from the water goes into the pasta, but not much of it,” explains Baker.
Similarly, some elements become trapped in minerals as they cool following a volcanic eruption.
Just as you could calculate salt concentrations in the water that cooked the pasta from analyzing salt in the pasta itself, the new technique allowed scientists to measure sulfur and fluorine in rock samples.
With this information, the scientists could calculate the amount of these gases released during the eruptions.
The study involved researchers from Italy, Norway, Sweden, the UK, the United States and Canada.
Their findings mark a step forward in piecing together Earth’s ancient secrets and pave the way for a more informed approach to our own changing climate.
Reference:
Sara Callegaro, Don R. Baker, Paul R. Renne, Leone Melluso, Kalotina Geraki, Martin J. Whitehouse, Angelo De Min, Andrea Marzoli. Recurring volcanic winters during the latest Cretaceous: Sulfur and fluorine budgets of Deccan Traps lavas. Science Advances, 2023; 9 (40) DOI: 10.1126/sciadv.adg8284
Fossilized Trisauropodiscus tracks and modern bird tracks. Credit: Abrahams et al., CC-BY 4.0 (creativecommons.org/licenses/by/4.0/)
Ancient animals were walking around on bird-like feet over 210 million years ago, according to a study published November 29, 2023 in the open-access journal PLOS ONE by Miengah Abrahams and Emese M. Bordy of the University of Cape Town, South Africa.
Numerous fossil sites in southern Africa preserve distinctive three-toed footprints that have been named Trisauropodiscus. For many years, researchers have debated what animals might have left these tracks, as well as precisely how many different species (technically called ichnospecies) of Trisauropodiscus there are.
In this study, the researchers reassessed the fossil record of these footprints, examining physical fossil traces alongside published materials documenting Trisauropodiscus at four sites in Lesotho dating to the Late Triassic and Early Jurassic Periods.
The authors also provided a detailed field-based description of footprints from an 80-meter-long tracksite in Maphutseng.
They identified two distinct morphologies among Trisauropodiscus footprints, the first of which is similar to certain non-bird dinosaur tracks, and the second of which is very similar in size and proportions to the footprints of birds.
These tracks aren’t a direct match for any fossil animals known from this region and time period.
The most ancient of these footprints, at over 210 million years old, are 60 million years older than the earliest known body fossils of true birds.
It’s possible that these tracks were produced by early dinosaurs, and potentially even early members of a near-bird lineage, but the authors note that there could also have been other reptiles, cousins of dinosaurs, that convergently evolved bird-like feet.
Whoever the trackmakers are, these footprints establish the origin of bird-like feet at least as early as the Late Triassic Period.
The authors add: “Trisauropodiscus tracks are known from numerous southern African sites dating back to approximately 215 million years ago. The shape of the tracks is consistent with modern and more recent fossil bird tracks, but it is likely a dinosaur with a bird-like foot produced Trisauropodiscus.”
Reference:
Miengah Abrahams, Emese M. Bordy. The oldest fossil bird-like footprints from the upper Triassic of southern Africa. PLOS ONE, 2023; 18 (11): e0293021 DOI: 10.1371/journal.pone.0293021
Note: The above post is reprinted from materials provided by PLOS.
Ancient plate tectonics in the Archean period differs from modern plate tectonics in the Phanerozoic period because of the higher mantle temperatures inside the early Earth, the thicker basaltic crust, and the non-depletion of melt-mobile incompatible trace elements in the mantle. Credit: Science China Press
The plate tectonics theory established in the 20th century has been successful in interpreting many geological phenomena, processes, and events that have occurred in the Phanerozoic.
However, the theory has often struggled to provide a coherent framework for interpreting geological records not only in the continental interior but also in the Precambrian period. In the traditional plate tectonics theory dealing with the relationship between plate tectonics and continental geology, continental interior tectonics was often separated from continental margin tectonics in the inheritance and development of their structure and composition.
This separation led to the illusion as if the plate tectonics theory is not applicable to Precambrian geology, particularly in interpreting the fundamental geological characteristics of Archean cratons.
This integrated study is presented by Prof. Yong-Fei Zheng at the University of Science and Technology of China. It focuses on available observations from Archean geology and inspects their interpretations against the following three characteristic features in the Archean Earth:
(1) convective mantle temperatures were as high as 1500-1700°C,
(2) newly formed basaltic oceanic crust was as thick as 30-40 km, and
(3) the asthenosphere had a composition similar to the primitive mantle rather than the depleted mantle at present. On this basis, the author has successfully applied the plate tectonics theory in the 21st century to the interpretation of major geological phenomena on Archean cratons. The results eliminate the illusion that the Archean continental crust did not originate from a regime of plate tectonics.
By upgrading the plate tectonics theory from the traditional kinematic model in the 20th century to a holistic kinematic-dynamic model in the 21st century and systematically examining the vertical transport of matter and energy at plate margins, it is evident that plate tectonics can interpret the common geological characteristics of Archean cratons, such as lithological associations, structural patterns, and metamorphic evolution.
By deciphering the structure and composition of convergent plate margins as well as their dynamics, the formation and evolution of continental crust since the Archean can be divided into ancient plate tectonics in the Precambrian and modern plate tectonics in the Phanerozoic.
This approach provides a new perspective on and deep insights into early Earth’s evolution and continental crust’s origin. It leads to the development of alternative tectonic models, envisaging vertical movements in the realm of stagnant lid tectonics, including not only bottom-up processes such as mantle plumes and heat pipes but also top-down processes such as lithospheric foundering and subduction.
In fact, these vertical processes were not unique to the Archean but persisted into the Phanerozoic. They result from mantle poloidal convection at different depths, not specific to any particular period in Earth’s history.
Furthermore, Archean tonalite-trondhjemite-granodiorite (TTG) rocks would result from partial melting of the over-thick basaltic oceanic crust at convergent plate margins. The structural patterns of gneissic domes and greenstone keels would result from the buoyancy-driven emplacement of TTG magmas and its interaction with the basaltic crust at fossil convergent margins, and komatiites in greenstone belts would be the product of mantle plume activity in the regime of ancient plate tectonics.
The widespread distribution of high-grade metamorphic rocks in a planar fashion, rather than in zones, is ascribed to the separation of the gneissic domes from the greenstone belts.
In addition, volcanic associations in the Archean are short of calc-alkaline andesites, suggesting the shortage of sediment accretionary wedges derived from weathering of granitic continental crust above oceanic subduction zones. Penrose-type ophiolites are absent in Archean igneous associations, which can be ascribed to the formation of basalt accretionary wedges during the subduction initiation of microplates when only the upper volcanic rocks of mid-ocean ridges were offscrapped from the incipiently subducting slab.
The absence of blueschist and eclogite, as well as classic paired metamorphic belts, suggests that convergent plate margins were over-thickened through either warm subduction or hard collision of the thick oceanic crust at moderate geothermal gradients. Therefore, only by correctly recognizing and understanding the nature of Archean cartons can plate tectonics reasonably interpret their fundamental geological characteristics.
As soon as the upgraded version of plate tectonic theory in the 21st century is integrated with the three characteristic features of Archean Earth, it can make revolutionary progress in resolving the previous challenges to interpretations of the Archean continental geology.
Therefore, this article provides robust arguments for deciphering the inheritance and development relationships between ancient and modern plate tectonics regimes. The results not only contribute to the origin and evolution of continental crust on early Earth but also shed light on the geodynamic mechanism of how early Earth evolved from stagnant lid tectonics to mobile lid tectonics.
Reference:
YongFei Zheng, Plate tectonics in the Archean: Observations versus interpretations, Science China Earth Sciences (2023). DOI: 10.1007/s11430-023-1210-5
Note: The above post is reprinted from materials provided by Science China Press.
Fossil of Timorebestia koprii—the largest known specimen, almost 30 cm or 12 inches long. Image Credit: Dr Jakob Vinther
Fossils of a new group of animal predators have been located in the Early Cambrian Sirius Passet fossil locality in North Greenland. These large worms may be some of the earliest carnivorous animals to have colonised the water column more than 518 million years ago, revealing a past dynasty of predators that scientists didn’t know existed.
The new fossil animals have been named Timorebestia, meaning ‘terror beasts’ in Latin.
Adorned with fins down the sides of their body, a distinct head with long antennae, massive jaw structures inside their mouth and growing to more than 30cm in length, these were some of the largest swimming animals in the Early Cambrian times.
“We have previously known that primitive arthropods were the dominant predators during the Cambrian, such as the bizarre-looking anomalocaridids,” said Dr Jakob Vinther from the University of Bristol’s Schools of Earth Sciences and Biological Sciences, a senior author on the study.
“Our research shows that these ancient ocean ecosystems were fairly complex with a food chain that allowed for several tiers of predators.
“Timorebestia were giants of their day and would have been close to the top of the food chain. That makes it equivalent in importance to some of the top carnivores in modern oceans, such as sharks and seals back in the Cambrian period.”
Inside the fossilised digestive system of Timorebestia, the researchers found remains of a common, swimming arthropod called Isoxys. “We can see these arthropods was a food source many other animals,” said Morten Lunde Nielsen, a former PhD student at Bristol and part of the current study.
“They are very common at Sirius Passet and had long protective spines, pointing both forwards and backwards. However, they clearly didn’t completely succeed in avoiding that fate, because Timorebestia munched on them in great quantities.”
Arrow worms are one of the oldest animal fossils from the Cambrian.
While arthropods appear in the fossil record about 521 to 529 million years ago, arrow worms can be traced back at least 538 million years back in time.
Dr Vinther explained: “Both arrow worms, and the more primitive Timorebestia, were swimming predators. We can therefore surmise that in all likelihood they were the predators that dominated the oceans before arthropods took off. Perhaps they had a dynasty of about 10-15 million years before they got superseded by other, and more successful, groups.”
Luke Parry from Oxford University, who was part of the study, added “Timorebestia is a really significant find for understanding where these jawed predators came from. Today, arrow worms have menacing bristles on the outside of their heads for catching prey, whereas Timorebestia has jaws inside its head. This is what we see in microscopic jaw worms today — organisms that arrow worms shared an ancestor with over half a billion years ago. Timorebestia and other fossils like it provide links between closely related organisms that today look very different.”
“Our discovery firms up how arrow worms evolved,” added Tae Yoon Park from the Korean Polar Research Institute, the other senior author and field expedition leader.
“We have found this preserved in Timorebestia and another fossil called Amiskwia. People have debated whether or not Amiskwia was closely related to arrow worms, as part of their evolutionary stem lineage. The preservation of these unique ventral ganglia gives us a great deal more confidence in this hypothesis.
“We are very excited to have discovered such unique predators in Sirius Passet. Over a series of expeditions to the very remote Sirius Passet in the furthest reaches of North Greenland more than 82,5? north, we have collected a great diversity of exciting new organisms. Thanks to the remarkable, exceptional preservation in Sirius Passet we can also reveal exciting anatomical details including their digestive system, muscle anatomy, and nervous systems.
“We have many more exciting findings to share in the coming years that will help show how the earliest animal ecosystems looked like and evolved.” Dr Park concludes.
Reference:
Tae-Yoon S. Park, Morten Lunde Nielsen, Luke A. Parry, Martin Vinther Sørensen, Mirinae Lee, Ji-Hoon Kihm, Inhye Ahn, Changkun Park, Giacinto de Vivo, M. Paul Smith, David A. T. Harper, Arne T. Nielsen, Jakob Vinther. A giant stem-group chaetognath. Science Advances, 2024; 10 (1) DOI: 10.1126/sciadv.adi6678
Limbunyasphaera operculata is a new species that shows a small door opening into the cell. Photo Credit: Riedman et al.
The sun has just set on a quiet mudflat in Australia’s Northern Territory; it’ll set again in another 19 hours. A young moon looms large over the desolate landscape. No animals scurry in the waning light. No leaves rustle in the breeze. No lichens encrust the exposed rock. The only hint of life is some scum in a few puddles and ponds. And among it lives a diverse microbial community of our ancient ancestors.
In a new account of exquisitely preserved microfossils, researchers at UC Santa Barbara and McGill University revealed that eukaryotic organisms had already evolved into a diverse array of forms even 1.64 billion years ago. The paper, published in the journal Papers in Paleontology, recounts an assemblage of eukaryotic fossils from an era early in the group’s evolutionary history. The authors describe four new taxa, as well as evidence of several advanced characteristics already present in these early eukaryotes.
“These are among the oldest eukaryotes that have ever been discovered,” explained lead author Leigh Anne Riedman, an assistant researcher in UCSB’s Department of Earth Science. “Yet, even in these first records we’re seeing a lot of diversity.”
Eukarya forms one of the major domains of life, encompassing the plant, animal and fungi clades, as well as all other groups whose cells have a membrane-bound nucleus, like protists and seaweeds. Many scientists had thought early eukaryotes were all fairly similar during the late Paleoproterozoic, and that diversification took place around 800 million years ago. But Riedman and her co-authors found fossils of a delightfully diverse, and complex, cast of characters in rock nearly twice as old.
Scientists knew from previous studies that eukaryotes had evolved by this time, but their diversity in this era was poorly understood. So Riedman headed to the Outback in late 2019. Within one week, she had collected about 430 samples from eight cores drilled by a prospecting company; they now reside in the library of the Northern Territory Geological Survey. The two cores used for this study spanned roughly 500 meters of stratigraphy, or 133 million years, with around 15 million years of significant deposition.
Riedman returned to the United States with shale and mudstone: remnants of an ancient coastal ecosystem that alternated between shallow, subtidal mudflats and coastal lagoons. A dip in hydrofluoric acid dissolved the matrix rock, concentrating the precious microfossils which she then analyzed under the microscope.
“We were hoping to find species with interesting and different characteristics to their cell walls,” Riedman said. She hoped that these features could shed light on what was happening within the cells during this time period. Reaching any conclusions about the cellular interior would require a great deal of sleuthing, though, since the fossils preserve only the exterior of the cells.
The researchers were surprised by the diversity and complexity preserved in these fossils. They recorded 26 taxa, including 10 previously undescribed species. The team found indirect evidence of cytoskeletons, as well as platy structures that suggest the presence of internal vesicles in which the plates were formed — perhaps ancestral to Golgi bodies, present in modern eukaryotic cells. Other microbes had cell walls made of bound fibers, similarly suggestive of the presence of a complex cytoskeleton.
The authors also found cells with a tiny trapdoor, evidence of a degree of sophistication. Some microbes can form a cyst to wait out unfavorable environmental conditions. In order to emerge, they need to be able to etch an opening in their protective shell. Making this door is a specialized process. “If you’re going to produce an enzyme that dissolves your cell wall, you need to be really careful about how you use that enzyme,” Riedman said. “So in one of the earliest records of eukaryotes, we’re seeing some pretty impressive levels of complexity.”
Many people in the field had thought this ability emerged later, and the evidence for it in this assemblage further emphasizes how diverse and advanced eukaryotes were even at this early juncture. “The assumption has always been that this is around the time that eukaryotes appeared. And now we think that people just haven’t explored older rocks,” said co-author Susannah Porter, an Earth science professor at UC Santa Barbara.
This paper is part of a larger project investigating early eukaryote evolution. Riedman and Porter want to know in what environments early eukaryotes were diversifying, why they were there, when they migrated to other places, and what adaptations they needed in order to fill those new niches.
A big part of this effort involves understanding when different characteristics of eukaryotes first arose. For instance, the authors are quite interested to learn whether these organisms were adapted to oxygenated or anoxic environments. The former would suggest that they had an aerobic metabolism, and possibly mitochondria. Every modern eukaryote that’s been found descends from ancestors that possessed mitochondria. This suggests that eukaryotes acquired the organelle very early on, and that it provided a significant advantage.
Riedman and Porter are currently working on a fresh account of eukaryote diversity through time. They’ve also collected even older samples from Western Australia and Minnesota. Meanwhile, their geochemist collaborators at McGill are spearheading a study on oxygen levels and preferred eukaryote habitats, aspects that could shed light on their evolution.
“These results are a directive to go look for older material, older eukaryotes, because this is clearly not the beginning of eukaryotes on Earth,” Riedman said.
Reference:
Leigh Anne Riedman, Susannah M. Porter, Maxwell A. Lechte, Angelo dos Santos, Galen P. Halverson. Early eukaryotic microfossils of the late Palaeoproterozoic Limbunya Group, Birrindudu Basin, northern Australia. Papers in Palaeontology, 2023; 9 (6) DOI: 10.1002/spp2.1538
Fossilized skin. Credit: Current Biology/Mooney et al.
Researchers have identified a 3D fragment of fossilized skin that is at least 21 million years than previously described skin fossils. The skin, which belonged to an early species of Paleozoic reptile, has a pebbled surface and most closely resembles crocodile skin. It’s the oldest example of preserved epidermis, the outermost layer of skin in terrestrial reptiles, birds, and mammals, which was an important evolutionary adaptation in the transition to life on land. The fossil is described on January 11 in the journal Current Biology along with several other specimens that were collected from the Richards Spur limestone cave system in Oklahoma.
“Every now and then we get an exceptional opportunity to glimpse back into deep time,” says first author Ethan Mooney, a paleontology graduate student at the University of Toronto who worked on the project as an undergraduate with paleontologist Robert Reisz at the University of Toronto.
“These types of discoveries can really enrich our understanding and perception of these pioneering animals.”
Skin and other soft tissues are rarely fossilized, but the researchers think that skin preservation was possible in this case because of the cave system’s unique features, which included fine clay sediments that slowed decomposition, oil seepage, and a cave environment that was likely an oxygenless environment.
“Animals would have fallen into this cave system during the early Permian and been buried in very fine clay sediments that delayed the decay process,” says Mooney.
“But the kicker is that this cave system was also an active oil seepage site during the Permian, and interactions between hydrocarbons in petroleum and tar are likely what allowed this skin to be preserved.”
The skin fossil is tiny — smaller than a fingernail. Microscopic examination undertaken by coauthor Tea Maho of the University of Toronto Mississauga revealed epidermal tissues, a hallmark of the skin of amniotes, the terrestrial vertebrate group that includes reptiles, birds, and mammals and which evolved from amphibian ancestors during the Carboniferous Period.
“We were totally shocked by what we saw because it’s completely unlike anything we would have expected,” says Mooney.
“Finding such an old skin fossil is an exceptional opportunity to peer into the past and see what the skin of some of these earliest animals may have looked like.”
The skin shares features with ancient and extant reptiles, including a pebbled surface similar to crocodile skin, and hinged regions between epidermal scales that resemble skin structures in snakes and worm lizards.
However, because the skin fossil is not associated with a skeleton or any other remains, it is not possible to identify what species of animal or body region the skin belonged to.
The fact that this ancient skin resembles the skin of reptiles alive today shows how important these structures are for survival in terrestrial environments.
“The epidermis was a critical feature for vertebrate survival on land,” says Mooney.
“It’s a crucial barrier between the internal body processes and the harsh outer environment.”
The researchers say that this skin may represent the ancestral skin structure for terrestrial vertebrates in early amniotes that allowed for the eventual evolution of bird feathers and mammalian hair follicles.
The skin fossil and other specimens were collected by lifelong paleontology enthusiasts Bill and Julie May at Richards Spur, a limestone cave system in Oklahoma that is an active quarry. The unique conditions at Richards Spur preserved many of the oldest examples of early terrestrial animals. The specimens are housed at the Royal Ontario Museum.
Reference:
Ethan D. Mooney, Tea Maho, R. Paul Philp, Joseph J. Bevitt, Robert R. Reisz. Paleozoic cave system preserves oldest-known evidence of amniote skin. Current Biology, 2024; DOI: 10.1016/j.cub.2023.12.008
Note: The above post is reprinted from materials provided by Cell Press.
Three-dimensional model of the only known picrodontid skull in top (left) and bottom (right) views. CT scan technology revealed previously unknown bones of the skull (colored on the right) that helped demonstrate that picrodontids are not primates as previously believed. Three-dimensional model of the only known picrodontid skull in top (left) and bottom (right) views. CT scan technology revealed previously unknown bones of the skull (colored on the right) that helped demonstrate that picrodontids are not primates as previously believed.
A research paper published in Royal Society’s Biology Letters on January 10 has revealed that picrodontids — an extinct family of placental mammals that lived several million years after the extinction of the dinosaurs — are not primates as previously believed.
The paper — co-authored by Jordan Crowell, an Anthropology Ph.D. candidate at the CUNY Graduate Center; Stephen Chester, an Associate Professor of Anthropology at Brooklyn College and the Graduate Center; and John Wible, Curator of Mammals at the Carnegie Museum of Natural History — is significant in that it settled a paleontological debate that has been brewing for over 100 years while helping to paint a more clear picture of primate evolution.
For the last 50 years, paleontologists have believed picrodontids, which were no larger than a mouse and likely ate foods such as fruit, nectar, and pollen, were primates, based on features of their teeth that they share with living primates.
But by using modern CT scan technology to analyze the only known preserved picrodontid skull in Brooklyn College’s Mammalian Evolutionary Morphology Laboratory, Crowell, the lead author on the paper, worked with Chester, the paper’s senior author, and Wible to determine they are not closely related to primates at all.
“While picrodontids share features of their teeth with living primates, the bones of the skull, specifically the bone that surrounds the ear, are unlike that of any living primate or close fossil relatives of primates,” Crowell said.
“This suggests picrodontids and primates independently evolved similarities of their teeth likely for similar diets. This study also highlights the importance of revisiting old specimens with updated techniques to examine them.”
Chester, who serves as Crowell’s Ph.D. adviser, has both a professional and personal interest in this research.
It was Chester’s colleague and “academic grandfather,” Professor Emeritus Frederick Szalay from CUNY’s Hunter College and the Graduate Center, who in 1968 first convincingly classified picrodontids as primates based on evidence from fossilized teeth.
Szalay studied the teeth of the only known picrodontid skull, Zanycteris paleocenus, for his research — the same skull this team examined with the new technology that led to their discovery.
“The Zanycteris cranium was prepared and partially submerged in plaster around 1917, so researchers studying this important specimen at the American Museum of Natural History were not aware of how much cranial anatomy was hidden over the last 100 years” Chester said.
“Micro-CT scanning has revolutionized the field of paleontology and allows researchers to discover so much more about previously studied fossils housed in natural history museum collections.”
The research was funded by grants Chester and Crowell secured through Brooklyn College from the National Science Foundation and The Leakey Foundation. Chester and Crowell are also currently working on several additional externally funded research projects focused on how primates and other mammals evolved following the extinction of the dinosaurs. They encourage undergraduates to contact them regarding funded research opportunities in the Mammalian Evolutionary Morphology Laboratory.
Reference:
Jordan W. Crowell, John R. Wible, Stephen G. B. Chester. Basicranial evidence suggests picrodontid mammals are not stem primates. Biology Letters, 2024; 20 (1) DOI: 10.1098/rsbl.2023.0335
The map of Nankai Trough in southeast Japan, where one of the team’s ongoing project is to image the fluids underneath seafloor. (Credit: Dr Lina GAO)
An international team of scientists led by Dr Xin LIU, Assistant Professor of the Department of Earth Sciences, The University of Hong Kong (HKU), along with seismologists from the USA and China, has recently introduced a new method called ambient noise differential adjoint tomography, which allows researchers to visualise rocks with fluids better, leading to potential advancements in the discovery of water and oil resources, as well as applications in urban geologic hazard and early warning systems for tsunamis and the understanding of the water cycle. Their findings have been published in the journal Nature Communications.
The method utilises a portable instrument called ‘seismometer’ to record the Earth’s natural vibrations, making it a cost-effective and easy way to study areas in cities and oceans.
Seismometers record ground motion in three dimensions: up-down, north-south, and east-west.
In the study, 42 seismometers were placed along a line across the Los Angeles basin from Long Beach to Whittier Narrows.
Researchers found that rocks about 1-2 km beneath the surface near the Newport-Inglewood Fault, a fault that causes earthquakes, contain a significant amount of fluids.
These rocks have tiny holes filled with fluids, which may explain the occurrence of small earthquakes in Long Beach, California.
The abundance of fluids within these tiny holes reduces friction along the fault plane, allowing the two rock blocks on either side to slide past each other more easily and generate small earthquakes.
The paper suggests that ambient noise differential adjoint tomography can be used to find water and oil resources without the need for expensive drilling.
This novel method generates images of the ground covered by seismometers, revealing how fast seismic waves travel in soils and rocks.
In some locations, the seismic wave travels much slower compared to other regions at the same depth, indicating the presence of fluid.
As water and oil are fluids in rocks, this method can identify rocks containing such fluids.
“Previously, groundwater aquifers or deep fluid reservoirs were difficult to find without drilling multiple expensive wells or costly seismic surveys with loud artificial sound that are not environmentally friendly on land or ocean. Using just weak seismic noise recordings by two dozen seismometers on land or seafloor, our new technique can create images containing fluid information within rocks, and pinpoint the location and depth of fluid-rich rocks,” said Dr Liu, who is also the first author of the journal paper.
Additionally, this innovative method can be used to create detailed images of the ground in urban areas and the deep ocean, serving various purposes such as assessing urban geologic hazards, implementing early warning systems for tsunamis and enhancing our understanding of the water cycle under the seafloor.
In urban settings, a series of land seismometers can be deployed over the area of interest.
In the ocean, a line of Ocean Bottom Seismometers (OBS) can be installed on the seafloor to record background vibrations.
In both cases, a detailed image is created right underneath the line of seismometers, providing information about the locations of loose soil/sediments and fluid-bearing rocks that directly relate to regions with slow seismic wave velocity.
“In conclusion, this innovative method has the potential to revolutionise our approach to discovering and utilising water and oil resources, enhancing urban safety measures, and deepening our understanding of the environment. Its direct impact on our daily lives spans from efficient resource exploration to effective disaster preparedness and promoting sustainable environmental management practices. This scientific breakthrough holds excellent promise in shaping a better future for us all,” Dr Liu added.
Reference:
Xin Liu, Gregory C. Beroza, Hongyi Li. Ambient noise differential adjoint tomography reveals fluid-bearing rocks near active faults in Los Angeles. Nature Communications, 2023; 14 (1) DOI: 10.1038/s41467-023-42536-4
Roman DiBiase, associate professor of geosciences at Penn State, stands on a boulder in a river channel in central Taiwan. Credit: Provided by Julia Carr . All Rights Reserved.
Drones flying along miles of rivers in the steep, mountainous terrain of central Taiwan and mapping the rock properties have revealed new clues about how water helps shape mountains over geological time, according to a team led by Penn State scientists.
The researchers found a link between the size of boulders in the rivers and the steepness of the rivers. The link shows how rock properties can influence the relationship between tectonic processes happening deep underground and how mountainous landscapes change shape. They reported in the journal Science Advances.
“Over the course of a mountain belt developing, we’re seeing differences in how rivers incise, or cut down into the bedrock, in the younger and older sections,” said Julia Carr, lead author of the study who earned her doctorate in geosciences from Penn State in 2022. “It means that as a mountain belt evolves, erosion is changing at the surface.”
As tectonic plates collide and form mountain ranges, rocks that were previously buried in the Earth’s crust are pushed to the surface in a process called uplift. The temperature and pressure that these rocks experience leads to variability in rock properties — like rock hardness or the spacing and orientation of fractures — that then affect how easily they are eroded by elements at the surface, the scientists said.
In Taiwan, the scientists found the main signature of rock strength of the mountains was the size of boulders in rivers, which were larger and stronger in locations where rocks had been buried deeper in Earth’s crust. And the size of boulders correlated with the steepness of the rivers, which must be powerful enough to move these boulders downstream before eroding the mountain, the scientists said.
“When the boulders in the channels are larger, the river needs to steepen to be able to erode at the same rate,” said Roman DiBiase, associate professor of geosciences at Penn State and co-author of the study. “This is because in order to erode rock, the sediment covering a river channel needs to move out of the way. The larger the boulders in the channel, the steeper the channel needs to be to move them.”
Models can account for how things like storms and floods impact erosion rates, but it’s harder to factor the role of rock strength on the process, the scientists said.
“Determining the controls on river incision into rock is important for understanding how mountain ranges evolve over geologic time,” DiBiase said. “But some key parameters for testing models of river incision, such as flow depth and sediment cover, are difficult to measure at large scales.”
The researchers turned to drones to avoid obstacles like hazardous river crossings and waterfalls to collect data. During these surveys, the scientists collected hundreds of thousands of measurements of river channel morphology and more than 22,000 measurements of boulders along roughly 18 miles of rivers.
“That’s where it’s really unprecedented — something of this scale is really unusual,” said Carr, who conducted the research at Penn State and is now a postdoctoral fellow at Simon Fraser University in British Columbia. “It’s exciting to be able to survey at this scale — it helps us see patterns we really would otherwise never see. If you just went into the field and surveyed the few spots you could get to easily, you would not observe this pattern.”
Taiwan’s central mountain range is one of the steepest landscapes on Earth and has one of the highest erosion rates of any place outside glaciated or human-influenced areas, Carr said. In addition, the tectonic setting of Taiwan is well known and has systematic burial depth patterns that can be used to evaluate the connection between subsurface history of rocks and their current condition at the surface.
“It’s this great unique place because unlike somewhere like the Himalayas or the Alps, where there’s so many complex tectonic histories, Taiwan can be a relatively simple landscape to study because the same collision forces that created it millions of years ago are still active today,” Carr said. “And these lessons learned from Taiwan can help inform erosion models that are applied to other mountain ranges with fewer constraints.”
Because of how the range formed, younger rocks are found in the south and west, while older rocks that were buried deeper — up to 24 miles underground — are found further east and north, the scientists said.
In the younger sections, rivers have fewer, smaller boulders that cover less of the area of the channels. And as you travel toward the older sections, the boulders increase to a median size of more than six feet, the scientists said.
These boulders aren’t sitting in the rivers waiting to be broken down over time, according to the researchers. Instead, boulders in each of the sections of rivers were close to the threshold of mobility — meaning the water was nearly powerful enough to move them downstream. During high flows after storms, these boulders may be fully mobile, and as they move, they help incise the river.
“One way you can think about how rivers incise long term — you need to be able to move sediment, and once you cross over some threshold, you can incise the river,” Carr said. “If we apply this, it implies this primary rock strength signal controlling boulder size is setting river incision in the landscape. And that matches with the local steepness of the rivers.”
Also contributing were Donald Fisher, professor of geosciences at Penn State; En-Chao Yeh, associate professor at National Taiwan Normal University; and Eric Kirby, professor at University of North Carolina at Chapel Hill.
The National Science Foundation supported this work.
Reference:
Julia C. Carr, Roman A. DiBiase, En-Chao Yeh, Donald M. Fisher, Eric Kirby. Rock properties and sediment caliber govern bedrock river morphology across the Taiwan Central Range. Science Advances, 2023; 9 (46) DOI: 10.1126/sciadv.adg6794
Note: The above post is reprinted from materials provided by Penn State. Original written by Matthew Carroll.
