Biology Paleontology

[Snake_Baker]

GTFoutta here

 

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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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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]

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.

Canada Unveils 'Dinosaur Mummy' Found With Skin And Gut Contents Intact | ARCHAEOLOGY WORLD

"We don't just have a skeleton," said one of the nodosaur researchers involved. "We have a dinosaur as it would have been."

www.archaeology-world.com

 

[Wizard17]

Giant lost carnivore found in museum drawer

A palaeontologist went rummaging around in some drawers in a Kenyan museum and found the biggest African meat-eating mammal of its day: Simbakubwa kutokaafrika.

www.abc.net.au

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."

 

[CD Xbow]

A fabulous series of mammalian fossils from the Colorado Denver Basin have been discovered https://www.nationalgeographic.com/...wth-spurt-after-dinosaurs-died-corral-bluffs/ which show the increase in size of mammals after the impact event that finished the Dinos. After the impact the surviving mammals were small, < 0.5kg, within 300,000 years they had got to 5-10 kg and by 700,000 years they had reached nearly 50kg.

Slightly off topic, my friend Peter Trusler is doing a reconstruction of a small mammal from the mid cretaceous period, which is based on a tiny piece of tail found in Burmese amber from about 90 mya. The paper hasn't been published yet. I've only seen pictures of the specimen, its about the last 1cm of tail, with skin and fur but no bone. You can see fleas and other insects in the amber. It's pretty mind blowing.

Burmese amber has been a rich source of fossils from many periods, there are even ammonite fossil in amber. How does an ammonite get into amber you may ask? Amber that gets into the sea though flooding or a vigorous geological event softens in salt water and is then thus able to catch sea creatures, a much better explanation than the famous 'Tree Climbing Ammonite of Myanmar'.

I spent a day at the SA museum last week, thoroughly recommend seeing the Ediacaran fossils and the marsupial megafauna. The Ediacaran fossils are really amazing, more than 600 million years old and magnificently detailed with incredible resolution.

 

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These will be real history makers if verified. Alleged Dino DNA - Dinosaur DNA and proteins found in fossils, paleontologists claim, and probably from even longer ago, the first alleged extra-terrestrial protein - put up at arxiv Hemolithin: a Meteoritic Protein containing Iron and Lithium. This comes from the re-examination of 2 meterorites, Acfer 086 and Allende with new technology.
Both awaiting peer review & official publishing

At a guess, the first won't be proven and the second, the extraterrestrial protein will be.

 

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Spinosaurus features in this visually impressive article.

Reconstructing Spinosaurus, a gigantic aquatic predator

Explore how scientists discovered the largest predator ever lived and hunted almost entirely in the water.

www.nationalgeographic.com

Shows the changes in reconstruction over time very nicely as more bones were found and the spines along the back have become a dorsal fin. All obvious...…now.

 

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Adalatherium, an oddball mammal from Madagascar in the late cretaceous, an absolutely magnificent find, extremely well-preserved and almost complete skeleton that amounts to the most complete fossil of a Gondwanan Mesozoic mammal ever found. It was cat sized, which despite the ScienceAlert article calling it small, it was actually big for mammals in the cretaceous, most were mouse to rat sized. See - https://www.sciencealert.com/crazy-...-mammal-skeleton-found-in-southern-hemisphere. Madagascar was part of Gondwana at the start of the Mesozoic, after which the whole continent just went to pieces - Africa, Antarctica, S. America, Australia etc.

Note The link title is incorrect, if you read the earlier post about mammals you will know that here in Oz we have Ausktribosphenos nyktos, which appears to be a placental mammal and is around 115 million years old and the earliest monotreme (monotremes are mammals, too) is 123 mya, Teinolophos trusslei. Nonetheless this is a real spectacular oddball for a number of archaic anatomical reasons.

Original at Nature if you have a subscription - https://www.nature.com/articles/s41586-020-2234-8

 

[CD Xbow]

For more than 50 years the 'Tully Monster' has been an mystery. It has some very unusual features, the long proboscis and the weird eyes on sticking out on stilts from a body a bit like a squid. It has remained unclassified, variously being called a mollusc, arthropod or vertebrate. These folks believe it's a vertebrate on biochemical grounds (evidence of collagen and no evidence of chiton) I liked the comment that looking at anatomic specimens of it is like looking at a Rorschach test. You see what you want to see. Note it's from the US, not from Tully in Oz.

Ancient 'Tully monster' was a vertebrate, not a spineless blob, study claims

An odd carboniferous creature with eyes like a hammerhead was this: a vertebrate.

www.livescience.com

Mind you it may not be definitive evidence and we will have to wait as see what other evidence turns up. It is a good example of modern techniques can shed new light on old specimens.

 

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This is a good BBC article about mammalian evolution - https://www.sciencefocus.com/nature/the-secret-world-of-mammal-evolution/
The really interesting bit is the yet to be officially described fossil from China of a probable furred mammal from the Mesozoic Era, from around 125 million years ago. Incredible specimen. Look at the detail of the fur. Large for a mammalian fossil of it's ilk. Those Chinese sediments that revealed all the feathered and fluffy dino's may do the same for Mesozoic mammals.

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[Werewolf]

A 10 metre long, 5 tonne crocodile with banana sized teeth! You wouldn't want to go swimming with that bad boy

'Terror crocodile' with banana-sized teeth ate dinosaurs

New specimens reveal further details of a 10-metre long prehistoric beast which scientists call the "terror crocodile" and which ate everything it encountered, including the largest of contemporary dinosaurs.

www.abc.net.au

 

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Scelidosaurus, was collected more than 160 years ago on west Dorset's Jurassic Coast from rocks that are around 193 million y.o. Richard Owen kept it in his cupboard after doing a cursory examination. I guess Sir Richard had bigger fish to fry. Scelidosaurus has recently been re-examined and is recognised as a basal ankylosaur, following on not much later than the it's ancestors the earliest ornithopods - https://phys.org/news/2020-08-dinosaur-skeleton-ready-closeup.html Unfortunately the link to the published article is behind a pay wall, you can read the abstract.

It was also the first complete dino specimen, seen here in it's death pose.

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This article https://phys.org/news/2020-08-fossil-evidence-hibernation-like-state-million-year-old.html describes evidence of a hibernation-like state in a Lystrosaurus that lived in Antarctica during the Early Triassic, some 250 million years ago. This is the oldest evidence of a hibernation-like state in a vertebrate animal, and indicates that torpor, a general term for hibernation and similar states in which animals temporarily lower their metabolic rate. Antarctica during Lystrosaurus' time lay largely within the Antarctic Circle, like today, and experienced extended periods without sunlight each winter.

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Lystrosaurus was a herbivorous genus of dicynodont therapsids (mammal precursors) from the late Permian and Early Triassic epochs that has been found all over the world. After surviving the end Permian extinction event, a significant achievement in itself, Lystrosaurus came to dominate the early Triassic. Why Lystrosaurus survived the extinction event and prospered in the early Triassic has been a mystery. It looks a rather unimpressive sort of animal. It may be it's physiology was it's trick. Undergoing hibernation suggests it is endothermic, there is evidence for fur in coprolites of other dicynodonts and microscopic bone structure looks like an endotherm. The ability to burrow probably also helped. It's certainly looking like many fundamental things that make our ideas of a mammal go back a very, very long time. The Triassic dried and warmed the archosaurs eventually displaced Lystrosaurus, the dicynodonts and cynodonts as the dominate vertebrates on land.

 

[CD Xbow]

Well, this is very good timing. See post above. Why Lystrosaurus and a whole lot of species went extinct in the early Triassic has been solved. Really solved. There was an event in the early Triassic called the Carnian Pluvial Episode (CPE). For many years it was thought to be a regional event, not global, however more data has been accumulated and it seems these Wrangellia eruptions may have killed as many species as the giant asteroid did. Ecosystems on land and sea were profoundly changed, as the planet got warmer and drier, and more suited to the archosaurs. Readable article by one of scientists, https://theconversation.com/newly-d...nt-triggered-the-dawn-of-the-dinosaurs-146248, link to the source in first para.

"The massive Wrangellia (Eastern Canada) eruptions pumped carbon dioxide, methane and water vapour into the atmosphere, leading to global warming and an increase in rainfall worldwide. There were as many as five pulses of eruptions associated with warming peaks from 233 million years ago. The eruptions led to acid rain as the volcanic gases mixed with rainwater to shower the Earth in dilute acid. Shallow oceans also became acidified. The sharp warming drove plants and animals from the tropics and the acid rain killed plants on land, while ocean acidification attacked all marine organisms with carbonate skeletons. "

So the Wrangellia eruptions ended Lystrosaurus rule of the land, and set the stage for the rise of the dino's (and friends).

 

[Werewolf]

World's most-complete triceratops skeleton to go on display in Melbourne in 2021

The 67-million-year-old fossil now being dug from rock on private land in the United States is the most complete and finely preserved triceratops ever found, comprising hundreds of bones.

www.abc.net.au