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What fossil eggs found in Alberta reveal about how dinosaurs became birds

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Seventy-five million years ago in southern Alberta, a river flooded, burying the eggs of bird-like dinosaurs nesting on the nearby plain. Now, tiny pieces of those fossil egg shells offer new evidence about how dinosaurs lived, bred and evolved into birds.

A new study shows emu-sized, meat-eating troodons were as warm-blooded as birds, with body temperatures of more than 40 C. But unlike modern birds such as chickens that can produce one egg a day, troodons used a very slow egg-forming process similar to the one used by reptiles like crocodiles.

That supports a previous hypothesis that nests found containing up to two dozen eggs were shared by multiple troodons, similar to the way ostriches share communal nests today.

“So essentially, from an eggshell … we were able to get and deduct information about their reproductive system and also their behaviour,” said Mattia Tagliavento, lead author of the study published Monday in Proceedings of the National Academy of Sciences.

François Therrien, curator of dinosaur paleobiology at the Royal Tyrell Museum in Alberta and co-author of the study, said he was surprised by just how much information could be gleaned from tiny fragments of eggshell no bigger than a fingernail.

How to read an eggshell

Eggshells have previously been used to estimate the body temperatures of some other kinds of dinosaurs, which vary from species to species.

Such estimates rely on the fact that eggshells contain carbonates — minerals made of carbon and oxygen atoms. Heavier forms of carbon and oxygen tend to cluster together more when the temperature is lower. So analyzing the amount of clustering reveals the temperature the eggshells formed in — that is, the dinosaur’s body temperature.

Both University of Calgary professor Darla Zelenitsky and Francois Therrien, a curator at the Royal Tyrell Museum, were part of teams that found troodon nests in southern Alberta. (Darla Zelenitsky)

Tagliavento, a postdoctoral researcher at Goethe University Frankfurt, said the technique can be accurate to within plus or minus 4 C.

In the new study, Tagliavento wanted to compare the eggshells of bird-like dinosaurs to modern birds and reptiles. He and his collaborators collected chicken eggs from a local farm, along with turtle and crocodile eggs, mostly from zoos. Knowing the the Royal Tyrell Museum in Alberta had a good collection of Late Cretaceous dinosaur eggs, he reached out to Therrien, who had collected troodon eggs himself in southern Alberta in the early 2000s.

Some had previously been collected in the 1990s by other paleontologists, including Darla Zelenitsky, an associate professor and paleontologist at the University of Calgary.

The nests and eggs were found in an area of Alberta that had a subtropical climate during the Late Cretaceous, but wasn’t as humid or forested as Dinosaur Provincial Park was at the time. Therrien said it would have been more open, with lower-growing vegetation, although grasses hadn’t yet evolved.

Zelenitsky said troodons would have roamed and hunted among birds, turtles, crocodiles, horned and duck-billed dinosaurs, and other small meat-eating bird-like dinosaurs.

Both Therrien and Zelenitsky ended up helping Tagliavento and co-authoring the study.

An illustration shows a troodon sitting on a nest. Fossil nests have been found with up to 24 eggs. A new study adds to evidence that such nests were shared by multiple females, and that troodons were warm-blooded and may have brooded their eggs. (Masato Hattori)

How birds and reptiles make and lay eggs

Therrien sent Tagliavento a small collection of fingernail-sized troodon eggshell fragments.

When Tagliavento first analyzed the dinosaur, bird and reptile eggshells, he found that they didn’t all follow the same pattern. It turned out that the measurements were affected not just by the temperature at which the eggshells formed, but how quickly.

Birds are very speedy egg producers. While a female has only one ovary, it can produce an egg a day. And within that day, the bird’s body can coat that egg with an eggshell, and lay it in a nest.

In contrast, reptiles have two ovaries, meaning they can produce two eggs at once. But they can’t make eggs as fast as birds. The reptilian process for coating the egg with an eggshell takes a week or two before the egg can be laid.

The researchers managed to correct for those differences by making some changes to their analytical technique.

In doing so, they saw that troodons produced eggs slowly like a reptile. Zelenitsky says a troodon female likely produced two eggs per ovary, every week or two. But its eggs were large (about the diameter of a goose egg, but twice as long), and unlike reptiles, researchers don’t think a troodon could accumulate eggs inside its body for weeks.

That means it would likely only lay four to six eggs per season — just a fraction of the two dozen eggs in a given nest.

This is a piece of eggshell from a troodon dinosaur. The fragments that were analyzed were roughly the size of a fingernail. (Darla Zelenitsky)

“Twenty-four eggs of that size looked a bit ambitious for a single individual,” Tagliavento said.

In fact, other researchers had previously suggested that troodon eggs were laid in communal nests.

“Now we have some analytical support to say that now yes, probably these troodons were sharing their nest,” Tagliavento said. “Which is a behaviour that now is observed in nature” among some birds such as ostriches.

Therrien said the combination of bird-like and reptile-like traits in such a bird-like dinosaur shows the transition from reptiles to birds was very gradual.

Just how warm-blooded was troodon?

From the eggshell analysis, the researchers were also able to read the body temperature at which the troodon eggs were formed.

Interestingly, they got two different results — some of the eggs formed at 42 C, similar to the body temperature of modern birds and a temperature previously reported for troodon.

But one appears to have formed at 29 C, which has also been reported for both troodon and related dinosaurs. That adds to evidence that troodon may have been able to lower its body temperature like some birds in order to save energy.

David Varricchio, a professor of paleobiology at Montana State University, wasn’t involved in the new study, but wrote a previous study proposing that troodons laid their eggs in pairs, based on their arrangement within the nest.

He thought they therefore had two ovaries, unlike birds, although he thought they had a more bird-like reproductive tract, based on the shape of the eggs and their appearance under a microscope.

He had also proposed that troodon sat on their eggs to hatch them, an activity known as brooding. Varricchio says this idea has become less controversial since then due to growing evidence.

In an email, he said the body temperatures found in the new study “would be consistent with brooding as we argued.”

But he said it was “curious” that the researchers found two different body temperatures, and he questioned whether an animal would produce an egg while trying to conserve energy by lowering its body temperature.

Eggshell analysis has great potential: researchers

Varricchio said the eggshell analysis technique used by the researchers holds great potential, but is still early in its application.

“I expect we will see many more eggshell and other fossil studies using this technique in the near future.”

An illustrated reconstruction of troodon, shows that it had feathers, and scientists believe it to be extremely bird-like. However, the new study shows it had a reptile-like way of producing eggs. (Alex Boersma/PNAS)

Tagliavento noted that in general, long-extinct animals such as dinosaurs don’t leave behind much more than fossil bones. “They don’t really give access or full access to the original biology.”

He said the eggshell analysis gives them “a window into these dinosaurs’ biology using something that before our work, we didn’t really imagine we could.”

 

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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