Paleontology

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CD Xbow

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I found something similar on my plate after my roast last night, bit smaller than that though. Dinosaur anatomy had an amazing ability to scale down to birds (= therapod dino) and scale up to a sauropod femur like in the picture.

Even more amazing though than the ability of the anatomy to scale, is what vastly different physiologies such different beasties must of had. 'Reptiles' including dinos & birds encompass every sort of different energetic strategy, from small low energy lizards, though to the super high performance metabolism of birds, including the giantism of low metabolism sauropods, and the big therapods with an 'in between' sort of metabolism.

The survivors we see today are small animals reflecting two ends of the metabolic spectrum amongst reptiles. The cretaceous giants all died, always a bad time to be big when the biosphere collapses. At the low metabolism end there are the 'classic' reptiles, lizards/snakes/turtles along with our degenerate low metabolism crocs. The other survivors were the naturally small but high metabolism & high performance birds. All the great archosaurs with physiologies falling between these two patterns died. Small high performance maniraptors couldn't cut despite having an almost bird like size, metabolism, feathers gliding and possibly even flying. Pterosaurs couldn't make it, despite flying. Ancestral crocodilians with their fully four chambered circulation didn't make it, only those crocs that evolved low metabolic physiology and matching lifestyle.

Palaeontologists identify things other than small size amongst the cretaceous survivors. Semiaquatic life style, generally carnivores or omnivores with a bit of a penchant for insects, and presumably, in the case of reptiles, us furballs. Interestingly lizards seem to be especially adept at catching insects while snakes seem especially adapted to catching mammals (infrared, fast acting poisons on mammalian muscle). Whoops, that's my PhD.
 
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CD Xbow

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https://phys.org/news/2019-08-dinosaurs-linked-oxygen.html
This paper links the rise of dinos 215 million years ago to an increase in oxygen levels in the late Triassic, which went up to 19%. Oxygen levels over time have been a bit controversial, many techniques use isotope ratios and from that O2 levels are 'derived'. This technique is seemingly a direct one and should be more reliable. Measured 02 from atmospheric bubbles in amber
 

Snake_Baker

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Canada Unveils ‘Dinosaur Mummy’ Found With Skin And Gut Contents Intact

August 16, 2019

Scientists hail it as perhaps the best-preserved dinosaur specimen ever uncovered. You can’t even see its bones.

That’s because, 110 million years later, those bones remain covered by the creature’s intact skin and armor.

Indeed, the Royal Tyrrell Museum of Palaeontology in Alberta, Canada recently unveiled a dinosaur so well-preserved that many have taken to calling it not a fossil, but an honest-to-goodness “dinosaur mummy.” With the creature’s skin, armor, and even some of its guts intact, researchers are astounded at its nearly unprecedented level of preservation. “We don’t just have a skeleton,” Caleb Brown, a researcher at the Royal Tyrrell Museum, told National Geographic. “We have a dinosaur as it would have been.”




When this dinosaur — a member of a new species named nodosaur — was alive, it was an enormous four-legged herbivore protected by a spiky, plated armor and weighing in at approximately 3,000 pounds.

Today, the mummified nodosaur is so intact that it still weighs 2,500 pounds.

How the dinosaur mummy could remain so intact is still something of a mystery, although as CNN says, researchers suggest that the creature “may have been swept away by a flooded river and carried out to sea, where it eventually sank. Over millions of years on the ocean floor, minerals took the place of the dinosaur’s armor and skin, preserving it in the lifelike form now on display.”

Although the nodosaur dinosaur mummy was so well-preserved, getting it into its current display form was still an arduous undertaking. The creature was, in fact, first discovered in 2011 when a crude oil mine worker accidentally discovered the specimen while on the job.

Since that lucky moment, it has taken researchers 7,000 hours over the course of the last six years to both tests the remains and prepare them for display at the Royal Tyrrell Museum, where visitors now have the chance to see the closest thing to a real-life dinosaur that the world has likely ever seen.





 

Wizard17

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Of all the places you could imagine discovering a giant meat-eating mammal, a drawer is probably not one.

Matthew Borths was studying fossils at the Nairobi National Museum in Kenya when he decided to have a poke around.

"On a lunch break I decided to pull open some different drawers just to kind of see what else was there," Dr Borths said.

"And one of the drawers I pulled out had this gigantic fossil in it."

Luckily for Dr Borths — and the world of palaeontology — his area of expertise just so happened to be an order of extinct meat-eating mammals called the hyaenodonta.

While he immediately recognised the lower jaw bone as a hyaenodont, he knew it was from a species that had not been described before.

"I was like, 'how did I not know this was here?' I felt really responsible," he said.

"I'm one of the few people on the planet that really cares about this group of animals."


Knowing he was onto something special, he contacted his research adviser who put him in touch with a colleague at Ohio University, Nancy Stevens, who had also done some palaeontology work in Kenya.

"When I contacted her, I discovered that yeah, she'd been in Nairobi about three years earlier than I had, and she'd had the exact same experience," Dr Borths said.

"She'd opened this drawer and was like, 'What is this? This is amazing!'

"She's also interested in all kinds of mammals ... but doesn't have as much insider knowledge of the carnivore evolution. That's kind of my little niche."

Together, they identified the species and figured out where it sat in the hyaenodonta order. They've published their findings on Thursday in the Journal of Vertebrate Palaeontology.

After six years, they concluded that the animal was the biggest meat-eating beast in Africa of its time, between about 23 and 20 million years ago.

A mammal with a head about the size of a rhino's and weighing in at around 1,500 kilograms, they called their discovery Simbakubwa kutokaafrika.

While "Simbakubwa" is a Swahili word meaning "big lion", the hyaenodonts aren't related to any modern-day African mammals.

How did a giant carnivore fly under the radar for so long?

The fossils were found decades before by a group of researchers on the hunt for ancient ape remains at a western Kenyan dig site called Meswa Bridge.

The palaeoanthropologists who found it were experts in apes, not quadripedal carnivores, and so put it away in a museum drawer for someone else to get to.

In their research into the Simbakubwa, Dr Borths and Dr Stevens discovered that plenty of other researchers had also opened the drawer before them.

But while they all expressed astonishment at what lay inside, they had other projects to get to and didn't possess the particular knowledge needed to recognise the find.

This highlights not only how niche a field of expertise can be in palaeontology, but the importance of museums.

Around the world, it's likely that there are millions of undescribed species sitting in collections awaiting classification.

In Australia, we name around 2,500 new species each year, according to Museums Victoria senior curator Kevin Rowe.

"We've described about 30 per cent of species in Australia," Dr Rowe said.

"That's around 192,000 species, but we estimate there's another 420,000 awaiting description."

Many of those are sitting in drawers of their own.

But at the current rate, it will take around 400 years to classify all of Australia's species, by which time many will be extinct.

In 2018, the Australian Academy of Science launched the Decadal Plan, which detailed a roadmap to radically boost the rate of taxonomic research in Australia.


The plan was endorsed by Sir David Attenborough, who said at the time that palaeontology around the world was being stripped of funding at a time when species are under the greatest threat.

"This has serious consequences for the future of life on Earth," he said.

While serendipity led to the discovery of Simbakubwa, we may end up losing many species before we even know they exist, Dr Rowe said.

"It's increasingly difficult because funding for taxonomy is getting harder and harder to get," he said.

"If you lose museums, you lose the ability to name and define species, [but] it's about getting the time and people to do that."
 

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