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2025-05-13 14:55:16 ·

#333;">Ancient 300-foot-tall mud waves gave rise to Atlantic Ocean

Researchers reviewed ocean floor samples collected during the Deep Sea Drilling Project in 1975.
Credit: Deposit Photos / Oleg Dorokhin
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There was a time long ago when the Atlantic Ocean didn’t exist.
The general understanding among geologists is that the body of water originated between 83 to 113 million years ago, when South America and Africa split into their two respective continents to form the Equatorial Atlantic Gateway.
However, Earth’s marine history appears to require a multimillion-year revision thanks to a recent discovery roughly half a mile beneath the ocean floor.
The evidence is explored in a study published in the June edition of the journal Global and Planetary Change.
According to geologists at the UK’s Heriot Watt University, gigantic waves of mud and sand sediment about 250 miles off the coast of Guinea-Bissau in West Africa indicate the Atlantic Ocean actually formed around four million years earlier than previous estimates.
To understand just how intense all of this movement was, imagine waves that are about half a mile long and over 300 feet high.
“A whole field formed in one particular location to the west of the Guinea Plateau, just at the final ‘pinch-point’ of the separating continents of South America and Africa,” study co-author Uisdean Nicholson explained in a statement.
Nicholson and their colleagues initially came across these layers of mud waves after comparing seismic data with core samples collected from wells during the Deep Sea Drilling Project (DSDP) of 1975.
Five layers in particular were utilized to recreate the tectonic processes that broke apart the ancient supercontinent of Gondwana during the Mesozoic Era.
“One layer was particularly striking: it included vast fields of sediment waves and ‘contourite drifts’—mud mounds that form under strong bottom currents,” said Nicholson.
These waves initially formed as dense, salty water poured out from the newly created Equatorial Atlantic Gateway, “like a giant waterfall that formed below the ocean surface,” he added.
Just before the geologic event, huge salt deposits formed at the bottom of what is now the South Atlantic.
After the gateway opened, the underground mudfall occurred when dense, relatively fresh Central Atlantic water in the north combined with very salty waters in the south.
The resulting sedimentary evidence examined by the study’s authors now indicates this opening seems to have started closer to 117 million years ago.
“This was a really important time in Earth’s history when the climate went through some major changes,” explained study co-author Débora Duarte.
“Up until 117 million years ago, the Earth had been cooling for some time, with huge amounts of carbon being stored in the emerging basins, likely lakes, of the Equatorial Atlantic.
But then the climate warmed significantly from 117 to 110 million years ago.”
Duarte and Nicholson believe part of that major climatic change helped from the Atlantic Ocean, as seawater inundated the newly formed basins.
“As the gateway gradually opened, this initially reduced the efficiency of carbon burial, which would have had an important warming effect,” said Duarte.
“And eventually, a full Atlantic circulation system emerged as the gateway grew deeper and wider, and the climate began a period of long-term cooling during the Late Cretaceous period.”
The ramifications go beyond revising Earth’s geological timeline or the gateway’s role in Mesozoic climate change.
Better understanding the influence of oceanic evolutionary journeys on ancient climate patterns can help to predict what the future holds for the planet.
“Today’s ocean currents play a key role in regulating global temperatures,” explained Nicholson.
“Disruptions, such as those caused by melting ice caps, could have profound consequences.”

#666;">المصدر: https://www.popsci.com/environment/how-old-is-atlantic-ocean/" style="color: #0066cc; text-decoration: none;">www.popsci.com

#0066cc;">#ancient #300foottall #mud #waves #gave #rise #atlantic #ocean #researchers #reviewed #floor #samples #collected #during #the #deep #sea #drilling #project #1975credit #deposit #photos #oleg #dorokhinget #popular #science #daily #newsletter #breakthroughs #discoveries #and #diy #tips #sent #every #weekdaythere #was #time #long #ago #when #didnt #existthe #general #understanding #among #geologists #that #body #water #originated #between #million #years #south #america #africa #split #into #their #two #respective #continents #form #equatorial #gatewayhowever #earths #marine #history #appears #require #multimillionyear #revision #thanks #recent #discovery #roughly #half #mile #beneath #floorthe #evidence #explored #study #published #june #edition #journal #global #planetary #changeaccording #uks #heriot #watt #university #gigantic #sand #sediment #about #miles #off #coast #guineabissau #west #indicate #actually #formed #around #four #earlier #than #previous #estimatesto #understand #just #how #intense #all #this #movement #imagine #are #over #feet #higha #whole #field #one #particular #location #guinea #plateau #final #pinchpoint #separating #coauthor #uisdean #nicholson #explained #statementnicholson #colleagues #initially #came #across #these #layers #after #comparing #seismic #data #with #core #from #wells #dsdp #1975five #were #utilized #recreate #tectonic #processes #broke #apart #supercontinent #gondwana #mesozoic #eraone #layer #particularly #striking #included #vast #fields #contourite #driftsmud #mounds #under #strong #bottom #currents #said #nicholsonthese #dense #salty #poured #out #newly #created #gateway #like #giant #waterfall #below #surface #addedjust #before #geologic #event #huge #salt #deposits #what #now #atlanticafter #opened #underground #mudfall #occurred #relatively #fresh #central #north #combined #very #waters #souththe #resulting #sedimentary #examined #studys #authors #indicates #opening #seems #have #started #closer #agothis #really #important #climate #went #through #some #major #changes #débora #duarteup #until #earth #had #been #cooling #for #amounts #carbon #being #stored #emerging #basins #likely #lakes #atlanticbut #then #warmed #significantly #agoduarte #believe #part #climatic #change #helped #seawater #inundated #basinsas #gradually #reduced #efficiency #burial #which #would #warming #effect #duarteand #eventually #full #circulation #system #emerged #grew #deeper #wider #began #period #longterm #late #cretaceous #periodthe #ramifications #beyond #revising #geological #timeline #gateways #role #changebetter #influence #oceanic #evolutionary #journeys #patterns #can #help #predict #future #holds #planettodays #play #key #regulating #temperatures #nicholsondisruptions #such #those #caused #melting #ice #caps #could #profound #consequences

Ancient 300-foot-tall mud waves gave rise to Atlantic Ocean

Researchers reviewed ocean floor samples collected during the Deep Sea Drilling Project in 1975. Credit: Deposit Photos / Oleg Dorokhin Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent every weekday. There was a time long ago when the Atlantic Ocean didn’t exist. The general understanding among geologists is that the body of water originated between 83 to 113 million years ago, when South America and Africa split into their two respective continents to form the Equatorial Atlantic Gateway. However, Earth’s marine history appears to require a multimillion-year revision thanks to a recent discovery roughly half a mile beneath the ocean floor. The evidence is explored in a study published in the June edition of the journal Global and Planetary Change. According to geologists at the UK’s Heriot Watt University, gigantic waves of mud and sand sediment about 250 miles off the coast of Guinea-Bissau in West Africa indicate the Atlantic Ocean actually formed around four million years earlier than previous estimates. To understand just how intense all of this movement was, imagine waves that are about half a mile long and over 300 feet high. “A whole field formed in one particular location to the west of the Guinea Plateau, just at the final ‘pinch-point’ of the separating continents of South America and Africa,” study co-author Uisdean Nicholson explained in a statement. Nicholson and their colleagues initially came across these layers of mud waves after comparing seismic data with core samples collected from wells during the Deep Sea Drilling Project (DSDP) of 1975. Five layers in particular were utilized to recreate the tectonic processes that broke apart the ancient supercontinent of Gondwana during the Mesozoic Era. “One layer was particularly striking: it included vast fields of sediment waves and ‘contourite drifts’—mud mounds that form under strong bottom currents,” said Nicholson. These waves initially formed as dense, salty water poured out from the newly created Equatorial Atlantic Gateway, “like a giant waterfall that formed below the ocean surface,” he added. Just before the geologic event, huge salt deposits formed at the bottom of what is now the South Atlantic. After the gateway opened, the underground mudfall occurred when dense, relatively fresh Central Atlantic water in the north combined with very salty waters in the south. The resulting sedimentary evidence examined by the study’s authors now indicates this opening seems to have started closer to 117 million years ago. “This was a really important time in Earth’s history when the climate went through some major changes,” explained study co-author Débora Duarte. “Up until 117 million years ago, the Earth had been cooling for some time, with huge amounts of carbon being stored in the emerging basins, likely lakes, of the Equatorial Atlantic. But then the climate warmed significantly from 117 to 110 million years ago.” Duarte and Nicholson believe part of that major climatic change helped from the Atlantic Ocean, as seawater inundated the newly formed basins. “As the gateway gradually opened, this initially reduced the efficiency of carbon burial, which would have had an important warming effect,” said Duarte. “And eventually, a full Atlantic circulation system emerged as the gateway grew deeper and wider, and the climate began a period of long-term cooling during the Late Cretaceous period.” The ramifications go beyond revising Earth’s geological timeline or the gateway’s role in Mesozoic climate change. Better understanding the influence of oceanic evolutionary journeys on ancient climate patterns can help to predict what the future holds for the planet. “Today’s ocean currents play a key role in regulating global temperatures,” explained Nicholson. “Disruptions, such as those caused by melting ice caps, could have profound consequences.”

المصدر: www.popsci.com

#ancient #300foottall #mud #waves #gave #rise #atlantic #ocean #researchers #reviewed #floor #samples #collected #during #the #deep #sea #drilling #project #1975credit #deposit #photos #oleg #dorokhinget #popular #science #daily #newsletter #breakthroughs #discoveries #and #diy #tips #sent #every #weekdaythere #was #time #long #ago #when #didnt #existthe #general #understanding #among #geologists #that #body #water #originated #between #million #years #south #america #africa #split #into #their #two #respective #continents #form #equatorial #gatewayhowever #earths #marine #history #appears #require #multimillionyear #revision #thanks #recent #discovery #roughly #half #mile #beneath #floorthe #evidence #explored #study #published #june #edition #journal #global #planetary #changeaccording #uks #heriot #watt #university #gigantic #sand #sediment #about #miles #off #coast #guineabissau #west #indicate #actually #formed #around #four #earlier #than #previous #estimatesto #understand #just #how #intense #all #this #movement #imagine #are #over #feet #higha #whole #field #one #particular #location #guinea #plateau #final #pinchpoint #separating #coauthor #uisdean #nicholson #explained #statementnicholson #colleagues #initially #came #across #these #layers #after #comparing #seismic #data #with #core #from #wells #dsdp #1975five #were #utilized #recreate #tectonic #processes #broke #apart #supercontinent #gondwana #mesozoic #eraone #layer #particularly #striking #included #vast #fields #contourite #driftsmud #mounds #under #strong #bottom #currents #said #nicholsonthese #dense #salty #poured #out #newly #created #gateway #like #giant #waterfall #below #surface #addedjust #before #geologic #event #huge #salt #deposits #what #now #atlanticafter #opened #underground #mudfall #occurred #relatively #fresh #central #north #combined #very #waters #souththe #resulting #sedimentary #examined #studys #authors #indicates #opening #seems #have #started #closer #agothis #really #important #climate #went #through #some #major #changes #débora #duarteup #until #earth #had #been #cooling #for #amounts #carbon #being #stored #emerging #basins #likely #lakes #atlanticbut #then #warmed #significantly #agoduarte #believe #part #climatic #change #helped #seawater #inundated #basinsas #gradually #reduced #efficiency #burial #which #would #warming #effect #duarteand #eventually #full #circulation #system #emerged #grew #deeper #wider #began #period #longterm #late #cretaceous #periodthe #ramifications #beyond #revising #geological #timeline #gateways #role #changebetter #influence #oceanic #evolutionary #journeys #patterns #can #help #predict #future #holds #planettodays #play #key #regulating #temperatures #nicholsondisruptions #such #those #caused #melting #ice #caps #could #profound #consequences

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Ancient 300-foot-tall mud waves gave rise to Atlantic Ocean

Researchers reviewed ocean floor samples collected during the Deep Sea Drilling Project in 1975. Credit: Deposit Photos / Oleg Dorokhin Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent every weekday. There was a time long ago when the Atlantic Ocean didn’t exist. The general understanding among geologists is that the body of water originated between 83 to 113 million years ago, when South America and Africa split into their two respective continents to form the Equatorial Atlantic Gateway. However, Earth’s marine history appears to require a multimillion-year revision thanks to a recent discovery roughly half a mile beneath the ocean floor. The evidence is explored in a study published in the June edition of the journal Global and Planetary Change. According to geologists at the UK’s Heriot Watt University, gigantic waves of mud and sand sediment about 250 miles off the coast of Guinea-Bissau in West Africa indicate the Atlantic Ocean actually formed around four million years earlier than previous estimates. To understand just how intense all of this movement was, imagine waves that are about half a mile long and over 300 feet high. “A whole field formed in one particular location to the west of the Guinea Plateau, just at the final ‘pinch-point’ of the separating continents of South America and Africa,” study co-author Uisdean Nicholson explained in a statement. Nicholson and their colleagues initially came across these layers of mud waves after comparing seismic data with core samples collected from wells during the Deep Sea Drilling Project (DSDP) of 1975. Five layers in particular were utilized to recreate the tectonic processes that broke apart the ancient supercontinent of Gondwana during the Mesozoic Era. “One layer was particularly striking: it included vast fields of sediment waves and ‘contourite drifts’—mud mounds that form under strong bottom currents,” said Nicholson. These waves initially formed as dense, salty water poured out from the newly created Equatorial Atlantic Gateway, “like a giant waterfall that formed below the ocean surface,” he added. Just before the geologic event, huge salt deposits formed at the bottom of what is now the South Atlantic. After the gateway opened, the underground mudfall occurred when dense, relatively fresh Central Atlantic water in the north combined with very salty waters in the south. The resulting sedimentary evidence examined by the study’s authors now indicates this opening seems to have started closer to 117 million years ago. “This was a really important time in Earth’s history when the climate went through some major changes,” explained study co-author Débora Duarte. “Up until 117 million years ago, the Earth had been cooling for some time, with huge amounts of carbon being stored in the emerging basins, likely lakes, of the Equatorial Atlantic. But then the climate warmed significantly from 117 to 110 million years ago.” Duarte and Nicholson believe part of that major climatic change helped from the Atlantic Ocean, as seawater inundated the newly formed basins. “As the gateway gradually opened, this initially reduced the efficiency of carbon burial, which would have had an important warming effect,” said Duarte. “And eventually, a full Atlantic circulation system emerged as the gateway grew deeper and wider, and the climate began a period of long-term cooling during the Late Cretaceous period.” The ramifications go beyond revising Earth’s geological timeline or the gateway’s role in Mesozoic climate change. Better understanding the influence of oceanic evolutionary journeys on ancient climate patterns can help to predict what the future holds for the planet. “Today’s ocean currents play a key role in regulating global temperatures,” explained Nicholson. “Disruptions, such as those caused by melting ice caps, could have profound consequences.”

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2025-05-13 14:55:01 ·

#333;">First Ever Pregnant Ichthyosaur from the Early Cretaceous Reveals Life in Prehistoric Seas

During an excavation, amidst the Patagonian winds and hard rock, a fossil began to turn green.
It was an unexpected reaction: the adhesive applied to protect the bones, fragile after millions of years beneath the ice, had interacted with plant matter trapped in the rock’s cracks.
This greenish hue earned the fossil the nickname Fiona, like the ogre from Shrek.But Fionais much more than a ogre-themed name.
It is the first complete ichthyosaur ever excavated in Chile and, even more remarkably, the only known pregnant female from the Hauterivian — a stage of the Early Cretaceous dating back 131 million years.
Her skeleton, discovered at the edge of the Tyndall Glacier in Torres del Paine National Park — an area increasingly exposed by glacial retreat — belongs to the species Myobradypterygius hauthali, originally described in Argentina from fragmentary remains.The discovery, led by Judith Pardo-Pérez, a researcher at the University of Magallanes and the Cabo de Hornos International Center (CHIC), and published in the Journal of Vertebrate Paleontology, offers an unprecedented glimpse into ancient marine life — from how these majestic reptiles reproduced to how they adapted to oceans vastly different from those of today.An Ichthyosaur Maternity Ward in Patagonia(Image Courtesy of Irene Viscor)So far, 88 ichthyosaurs have been found on the Tyndall Glacier.
Most of them are adults and newborns.
Two key facts stand out: food was abundant, and no other predators were competing with them.Fiona, who measures nearly 13 feet long, is still encased in five blocks of rock.
Despite the challenge, she was transported to a local clinic, where CT scans allowed researchers to study her skull and body.
Her species was identified thanks to one of her fins.
“There’s no other like it in the world,” says Pardo-Pérez.
The limbs were remarkably elongated, suggesting this animal was built for long-distance swimming.Inside her, there were more surprises.
One of them was her stomach contents, which revealed what may have been her last meal: tiny fish vertebrae.
But the most striking find was a fetus, about 20 inches long, already in a position to be born.“We believe these animals came to Magallanes — the southern tip of Chilean Patagonia — from time to time to give birth, because it was a safe refuge,” Pardo-Pérez says.
“We don't know how long they stayed, but we do know that mortality was high during the first few days of life.”One of the big unanswered questions is where they went next, as there are no records of Myobradypterygius hauthali, apart from a piece of fin found in Argentina.
The most abundant remains come from southern Germany, but those date back to the Jurassic period, meaning they’re older.Palaeontologist Erin Maxwell suggests, “In many modern ecosystems, species migrate to higher latitudes during the summer to take advantage of seasonally abundant resources and then move to lower latitudes in winter to avoid harsh conditions,” she explains.
“We believe Mesozoic marine reptiles may have followed similar seasonal patterns.”Sea Dragon GraveyardThe environment where Fiona was discovered — dubbed the "sea dragon graveyard" — also has much to reveal.According to geologist Matthew Malkowski of the University of Texas at Austin, the Hauterivian age is particularly intriguing because it coincided with major planetary changes: the breakup of continents, intense volcanic episodes, and phenomena known as "oceanic anoxic events," during which vast areas of the ocean were depleted of dissolved oxygen for hundreds of thousands of years.One such poorly understood event, the Pharaonic Anoxic Event, occurred around 131 million years ago, near the end of the Hauterivian, and still raises questions about its true impact on marine life.
“We don't have a firm grasp of how significant these events were for marine vertebrates, and geological records like that of the Tyndall Glacier allow us to explore the relationship between life, the environment, and Earth’s past conditions,” Malkowski notes.Evolution of IchthyosaursReconstruction of Fiona.
(Image Courtesy of Mauricio Álvarez)Don't be misled by their body shape.
“Ichthyosaurs are not related to dolphins,” clarifies Pardo-Pérez.
Although their hydrodynamic silhouettes may look nearly identical, the former were marine reptiles, while the latter are mammals.
This resemblance results from a phenomenon known as convergent evolution: when species from different lineages develop similar anatomical features to adapt to the same environment.Ichthyosaurs evolved from terrestrial reptiles that, in response to ecological and climatic changes, began spending more time in the water until they fully adapted to a marine lifestyle.
However, they retained traces of their land-dwelling ancestry, such as a pair of hind flippers — absent in dolphins — passed down from their walking forebears.
They lived and thrived in prehistoric oceans for about 180 million years, giving them ample time to refine a highly specialized body: their forelimbs and hindlimbs transformed into flippers; they developed a crescent-shaped tail for propulsion, a dorsal fin for stability, and a streamlined body to reduce drag in the water.
Remarkably, like whales and dolphins, “ichthyosaurs had a thick layer of blubber as insulation to maintain a higher body temperature than the surrounding seawater and gave birth to live young, which meant they didn’t need to leave the water to reproduce,” explains Maxwell.Whales and dolphins also descend from land-dwelling ancestors, but their transition happened over a comparatively short evolutionary timespan, especially when measured against the long reign of the ichthyosaurs.
“Their evolution hasn't had as much time as that of ichthyosaurs,” notes Pardo-Pérez.
“And yet, they look so similar.
That’s the wonderful thing about evolution.”Read More: Did a Swimming Reptile Predate the Dinosaurs?Fossils on the Verge of DisappearanceOne of the key factors behind the remarkable preservation of the fossils found in the Tyndall Glacier is the way they were buried.
According to Malkowski, Fiona and her contemporaries were either trapped or swiftly covered by underwater landslides and turbidity currents — geological processes that led to their sudden entombment.But the good fortune that protected them for millions of years may now be running out.
As the glacier retreats, exposing fossils that were once unreachable, those same remains are now vulnerable to wind, rain, and freeze-thaw cycles, which crack the surrounding rock.
As vegetation takes hold, roots accelerate erosion and eventually conceal the fossils once again.“While climate change has allowed these fossils to be studied, continued warming will also eventually lead to their loss,” Maxwell warns.
In Fiona’s story, scientists find not only a record of ancient life, but also a warning etched in stone and bone: what time reveals, climate can reclaim.Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards.
Review the sources used below for this article:María de los Ángeles Orfila is a science journalist based in Montevideo, Uruguay, focusing on long-form storytelling.
Her work has appeared in Discover Magazine, Science, National Geographic, among other outlets, and in leading Uruguayan publications such as El País and El Observador.
She was a fellow in the 2023 Sharon Dunwoody Mentoring Program by The Open Notebook and often explores the intersections of science, culture, and Latin American identity.

#666;">المصدر: https://www.discovermagazine.com/the-sciences/first-ever-pregnant-ichthyosaur-from-the-early-cretaceous-reveals-life-in" style="color: #0066cc; text-decoration: none;">www.discovermagazine.com

#0066cc;">#first #ever #pregnant #ichthyosaur #from #the #early #cretaceous #reveals #life #prehistoric #seas #during #excavation #amidst #patagonian #winds #and #hard #rock #fossil #began #turn #greenit #was #unexpected #reaction #adhesive #applied #protect #bones #fragile #after #millions #years #beneath #ice #had #interacted #with #plant #matter #trapped #rocks #cracksthis #greenish #hue #earned #nickname #fiona #like #ogre #shrekbut #fionais #much #more #than #ogrethemed #nameit #complete #excavated #chile #even #remarkably #only #known #female #hauterivian #stage #dating #back #million #yearsher #skeleton #discovered #edge #tyndall #glacier #torres #del #paine #national #park #area #increasingly #exposed #glacial #retreat #belongs #species #myobradypterygius #hauthali #originally #described #argentina #fragmentary #remainsthe #discovery #led #judith #pardopérez #researcher #university #magallanes #cabo #hornos #international #center #chic #published #journal #vertebrate #paleontology #offers #unprecedented #glimpse #into #ancient #marine #how #these #majestic #reptiles #reproduced #they #adapted #oceans #vastly #different #those #todayan #maternity #ward #patagoniaimage #courtesy #irene #viscorso #far #ichthyosaurs #have #been #found #glaciermost #them #are #adults #newbornstwo #key #facts #stand #out #food #abundant #other #predators #were #competing #themfiona #who #measures #nearly #feet #long #still #encased #five #blocks #rockdespite #challenge #she #transported #local #clinic #where #scans #allowed #researchers #study #her #skull #bodyher #identified #thanks #one #finstheres #world #says #pardopérezthe #limbs #elongated #suggesting #this #animal #built #for #longdistance #swimminginside #there #surprisesone #stomach #contents #which #revealed #what #may #last #meal #tiny #fish #vertebraebut #most #striking #find #fetus #about #inches #already #position #bornwe #believe #animals #came #southern #tip #chilean #patagonia #time #give #birth #because 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First Ever Pregnant Ichthyosaur from the Early Cretaceous Reveals Life in Prehistoric Seas

During an excavation, amidst the Patagonian winds and hard rock, a fossil began to turn green. It was an unexpected reaction: the adhesive applied to protect the bones, fragile after millions of years beneath the ice, had interacted with plant matter trapped in the rock’s cracks. This greenish hue earned the fossil the nickname Fiona, like the ogre from Shrek.But Fionais much more than a ogre-themed name. It is the first complete ichthyosaur ever excavated in Chile and, even more remarkably, the only known pregnant female from the Hauterivian — a stage of the Early Cretaceous dating back 131 million years. Her skeleton, discovered at the edge of the Tyndall Glacier in Torres del Paine National Park — an area increasingly exposed by glacial retreat — belongs to the species Myobradypterygius hauthali, originally described in Argentina from fragmentary remains.The discovery, led by Judith Pardo-Pérez, a researcher at the University of Magallanes and the Cabo de Hornos International Center (CHIC), and published in the Journal of Vertebrate Paleontology, offers an unprecedented glimpse into ancient marine life — from how these majestic reptiles reproduced to how they adapted to oceans vastly different from those of today.An Ichthyosaur Maternity Ward in Patagonia(Image Courtesy of Irene Viscor)So far, 88 ichthyosaurs have been found on the Tyndall Glacier. Most of them are adults and newborns. Two key facts stand out: food was abundant, and no other predators were competing with them.Fiona, who measures nearly 13 feet long, is still encased in five blocks of rock. Despite the challenge, she was transported to a local clinic, where CT scans allowed researchers to study her skull and body. Her species was identified thanks to one of her fins. “There’s no other like it in the world,” says Pardo-Pérez. The limbs were remarkably elongated, suggesting this animal was built for long-distance swimming.Inside her, there were more surprises. One of them was her stomach contents, which revealed what may have been her last meal: tiny fish vertebrae. But the most striking find was a fetus, about 20 inches long, already in a position to be born.“We believe these animals came to Magallanes — the southern tip of Chilean Patagonia — from time to time to give birth, because it was a safe refuge,” Pardo-Pérez says. “We don't know how long they stayed, but we do know that mortality was high during the first few days of life.”One of the big unanswered questions is where they went next, as there are no records of Myobradypterygius hauthali, apart from a piece of fin found in Argentina. The most abundant remains come from southern Germany, but those date back to the Jurassic period, meaning they’re older.Palaeontologist Erin Maxwell suggests, “In many modern ecosystems, species migrate to higher latitudes during the summer to take advantage of seasonally abundant resources and then move to lower latitudes in winter to avoid harsh conditions,” she explains. “We believe Mesozoic marine reptiles may have followed similar seasonal patterns.”Sea Dragon GraveyardThe environment where Fiona was discovered — dubbed the "sea dragon graveyard" — also has much to reveal.According to geologist Matthew Malkowski of the University of Texas at Austin, the Hauterivian age is particularly intriguing because it coincided with major planetary changes: the breakup of continents, intense volcanic episodes, and phenomena known as "oceanic anoxic events," during which vast areas of the ocean were depleted of dissolved oxygen for hundreds of thousands of years.One such poorly understood event, the Pharaonic Anoxic Event, occurred around 131 million years ago, near the end of the Hauterivian, and still raises questions about its true impact on marine life. “We don't have a firm grasp of how significant these events were for marine vertebrates, and geological records like that of the Tyndall Glacier allow us to explore the relationship between life, the environment, and Earth’s past conditions,” Malkowski notes.Evolution of IchthyosaursReconstruction of Fiona. (Image Courtesy of Mauricio Álvarez)Don't be misled by their body shape. “Ichthyosaurs are not related to dolphins,” clarifies Pardo-Pérez. Although their hydrodynamic silhouettes may look nearly identical, the former were marine reptiles, while the latter are mammals. This resemblance results from a phenomenon known as convergent evolution: when species from different lineages develop similar anatomical features to adapt to the same environment.Ichthyosaurs evolved from terrestrial reptiles that, in response to ecological and climatic changes, began spending more time in the water until they fully adapted to a marine lifestyle. However, they retained traces of their land-dwelling ancestry, such as a pair of hind flippers — absent in dolphins — passed down from their walking forebears. They lived and thrived in prehistoric oceans for about 180 million years, giving them ample time to refine a highly specialized body: their forelimbs and hindlimbs transformed into flippers; they developed a crescent-shaped tail for propulsion, a dorsal fin for stability, and a streamlined body to reduce drag in the water. Remarkably, like whales and dolphins, “ichthyosaurs had a thick layer of blubber as insulation to maintain a higher body temperature than the surrounding seawater and gave birth to live young, which meant they didn’t need to leave the water to reproduce,” explains Maxwell.Whales and dolphins also descend from land-dwelling ancestors, but their transition happened over a comparatively short evolutionary timespan, especially when measured against the long reign of the ichthyosaurs. “Their evolution hasn't had as much time as that of ichthyosaurs,” notes Pardo-Pérez. “And yet, they look so similar. That’s the wonderful thing about evolution.”Read More: Did a Swimming Reptile Predate the Dinosaurs?Fossils on the Verge of DisappearanceOne of the key factors behind the remarkable preservation of the fossils found in the Tyndall Glacier is the way they were buried. According to Malkowski, Fiona and her contemporaries were either trapped or swiftly covered by underwater landslides and turbidity currents — geological processes that led to their sudden entombment.But the good fortune that protected them for millions of years may now be running out. As the glacier retreats, exposing fossils that were once unreachable, those same remains are now vulnerable to wind, rain, and freeze-thaw cycles, which crack the surrounding rock. As vegetation takes hold, roots accelerate erosion and eventually conceal the fossils once again.“While climate change has allowed these fossils to be studied, continued warming will also eventually lead to their loss,” Maxwell warns. In Fiona’s story, scientists find not only a record of ancient life, but also a warning etched in stone and bone: what time reveals, climate can reclaim.Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:María de los Ángeles Orfila is a science journalist based in Montevideo, Uruguay, focusing on long-form storytelling. Her work has appeared in Discover Magazine, Science, National Geographic, among other outlets, and in leading Uruguayan publications such as El País and El Observador. She was a fellow in the 2023 Sharon Dunwoody Mentoring Program by The Open Notebook and often explores the intersections of science, culture, and Latin American identity.

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First Ever Pregnant Ichthyosaur from the Early Cretaceous Reveals Life in Prehistoric Seas

During an excavation, amidst the Patagonian winds and hard rock, a fossil began to turn green. It was an unexpected reaction: the adhesive applied to protect the bones, fragile after millions of years beneath the ice, had interacted with plant matter trapped in the rock’s cracks. This greenish hue earned the fossil the nickname Fiona, like the ogre from Shrek.But Fionais much more than a ogre-themed name. It is the first complete ichthyosaur ever excavated in Chile and, even more remarkably, the only known pregnant female from the Hauterivian — a stage of the Early Cretaceous dating back 131 million years. Her skeleton, discovered at the edge of the Tyndall Glacier in Torres del Paine National Park — an area increasingly exposed by glacial retreat — belongs to the species Myobradypterygius hauthali, originally described in Argentina from fragmentary remains.The discovery, led by Judith Pardo-Pérez, a researcher at the University of Magallanes and the Cabo de Hornos International Center (CHIC), and published in the Journal of Vertebrate Paleontology, offers an unprecedented glimpse into ancient marine life — from how these majestic reptiles reproduced to how they adapted to oceans vastly different from those of today.An Ichthyosaur Maternity Ward in Patagonia(Image Courtesy of Irene Viscor)So far, 88 ichthyosaurs have been found on the Tyndall Glacier. Most of them are adults and newborns. Two key facts stand out: food was abundant, and no other predators were competing with them.Fiona, who measures nearly 13 feet long, is still encased in five blocks of rock. Despite the challenge, she was transported to a local clinic, where CT scans allowed researchers to study her skull and body. Her species was identified thanks to one of her fins. “There’s no other like it in the world,” says Pardo-Pérez. The limbs were remarkably elongated, suggesting this animal was built for long-distance swimming.Inside her, there were more surprises. One of them was her stomach contents, which revealed what may have been her last meal: tiny fish vertebrae. But the most striking find was a fetus, about 20 inches long, already in a position to be born.“We believe these animals came to Magallanes — the southern tip of Chilean Patagonia — from time to time to give birth, because it was a safe refuge,” Pardo-Pérez says. “We don't know how long they stayed, but we do know that mortality was high during the first few days of life.”One of the big unanswered questions is where they went next, as there are no records of Myobradypterygius hauthali, apart from a piece of fin found in Argentina. The most abundant remains come from southern Germany, but those date back to the Jurassic period, meaning they’re older.Palaeontologist Erin Maxwell suggests, “In many modern ecosystems, species migrate to higher latitudes during the summer to take advantage of seasonally abundant resources and then move to lower latitudes in winter to avoid harsh conditions,” she explains. “We believe Mesozoic marine reptiles may have followed similar seasonal patterns.”Sea Dragon GraveyardThe environment where Fiona was discovered — dubbed the "sea dragon graveyard" — also has much to reveal.According to geologist Matthew Malkowski of the University of Texas at Austin, the Hauterivian age is particularly intriguing because it coincided with major planetary changes: the breakup of continents, intense volcanic episodes, and phenomena known as "oceanic anoxic events," during which vast areas of the ocean were depleted of dissolved oxygen for hundreds of thousands of years.One such poorly understood event, the Pharaonic Anoxic Event, occurred around 131 million years ago, near the end of the Hauterivian, and still raises questions about its true impact on marine life. “We don't have a firm grasp of how significant these events were for marine vertebrates, and geological records like that of the Tyndall Glacier allow us to explore the relationship between life, the environment, and Earth’s past conditions,” Malkowski notes.Evolution of IchthyosaursReconstruction of Fiona. (Image Courtesy of Mauricio Álvarez)Don't be misled by their body shape. “Ichthyosaurs are not related to dolphins,” clarifies Pardo-Pérez. Although their hydrodynamic silhouettes may look nearly identical, the former were marine reptiles, while the latter are mammals. This resemblance results from a phenomenon known as convergent evolution: when species from different lineages develop similar anatomical features to adapt to the same environment.Ichthyosaurs evolved from terrestrial reptiles that, in response to ecological and climatic changes, began spending more time in the water until they fully adapted to a marine lifestyle. However, they retained traces of their land-dwelling ancestry, such as a pair of hind flippers — absent in dolphins — passed down from their walking forebears. They lived and thrived in prehistoric oceans for about 180 million years, giving them ample time to refine a highly specialized body: their forelimbs and hindlimbs transformed into flippers; they developed a crescent-shaped tail for propulsion, a dorsal fin for stability, and a streamlined body to reduce drag in the water. Remarkably, like whales and dolphins, “ichthyosaurs had a thick layer of blubber as insulation to maintain a higher body temperature than the surrounding seawater and gave birth to live young, which meant they didn’t need to leave the water to reproduce,” explains Maxwell.Whales and dolphins also descend from land-dwelling ancestors, but their transition happened over a comparatively short evolutionary timespan, especially when measured against the long reign of the ichthyosaurs. “Their evolution hasn't had as much time as that of ichthyosaurs,” notes Pardo-Pérez. “And yet, they look so similar. That’s the wonderful thing about evolution.”Read More: Did a Swimming Reptile Predate the Dinosaurs?Fossils on the Verge of DisappearanceOne of the key factors behind the remarkable preservation of the fossils found in the Tyndall Glacier is the way they were buried. According to Malkowski, Fiona and her contemporaries were either trapped or swiftly covered by underwater landslides and turbidity currents — geological processes that led to their sudden entombment.But the good fortune that protected them for millions of years may now be running out. As the glacier retreats, exposing fossils that were once unreachable, those same remains are now vulnerable to wind, rain, and freeze-thaw cycles, which crack the surrounding rock. As vegetation takes hold, roots accelerate erosion and eventually conceal the fossils once again.“While climate change has allowed these fossils to be studied, continued warming will also eventually lead to their loss,” Maxwell warns. In Fiona’s story, scientists find not only a record of ancient life, but also a warning etched in stone and bone: what time reveals, climate can reclaim.Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:María de los Ángeles Orfila is a science journalist based in Montevideo, Uruguay, focusing on long-form storytelling. Her work has appeared in Discover Magazine, Science, National Geographic, among other outlets, and in leading Uruguayan publications such as El País and El Observador. She was a fellow in the 2023 Sharon Dunwoody Mentoring Program by The Open Notebook and often explores the intersections of science, culture, and Latin American identity.

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First Ever Pregnant Ichthyosaur from the Early Cretaceous Reveals Life in Prehistoric Seas