T-rex ancestor found in China

 

The earliest known forerunner of the Tyrannosaurus rex, Guanlong wucaii, has been found in China.

AFP/Zhongda Zhang-IVPP

Fossil hunters in China say they have found the earliest known forerunner of the Tyrannosaurus rex, the mighty flesh-ripping dinosaur beloved of children and Hollywood.

Uncovered in Wucaiwan in the western province of Xinjiang, the species has been dubbed Guanlong wucaii, "crowned dragon of the five-coloured rocks", a reference to the tint of the earth in which it was found.

It hails from the Late Jurassic Period, around 161 million to 156 million years ago, according to the discoverers, led by Xu Xing of the Institute of Vertebrate Palaeontology and Palaeoanthropology in Beijing.

By comparison, the T-rex lived much later, in the Late Cretaceous era, enjoying a 20-million-year reign of terror that ended with the extinction of the dinosaurs some 65 million years ago.

Nose to tail, T-rex measured up to 13 metres in length, whereas the best preserved of the two fossils unearthed in Wucaiwan suggest a creature that was about three metres long.

Despite these differences, the "crowned dragon" shows all the key ancestral hallmarks of the tyrannosaurids.

It shares their enlarged skull, two powerful rear feet, stubby forelimbs that end in a powerful three-fingered hand and long, blade-like teeth that suggests it too was a predator to be reckoned with.

But palaeontologist believe the "primitive" look of the pelvis also suggests something else.

It supports a theory first put forward in the 1990s that the tyrannosaurids, despite their great size, evolved from a species of swift, small-bodied dinosaurs called coelurosaurs.

Guanlong also had a highly elaborate, fragile crest, a "crown" that ran almost the entirely length of its long upper jaw.

This crest is "surprising," given that it would have surely hampered the beast in its hunt for food, the palaeontologists say.

They speculate that it was an ornament that may have been used to lure a mate or show off status. Many vertebrate species today use these tools, such as peacocks with their tails and elks with their antlers, even if the device carries a cost in movement.

Xu has earned a reputation for being the world's most successful fossil finder, unearthing extraordinary specimens that have shed light in particular on birds, spurring the theory that modern birds are the descendants of dinosaurs.

Most of his big finds have come from lake deposits in Liaoning province, in the north east of China, that are between 128 and 110 million years old.

Their study is published in Nature, the British weekly science journal.

 

Carnivorous baby dinosaurs were born with teeth and 'ready to hunt', scientists find

 

A baby tyrannosaur from the Cretaceous Period of North America, based on partial fossils unearthed in the US. (Reuters: Julius Csotonyi)

Silhouettes of two baby tyrannosaurs based on partial fossils unearthed in the US state of Montana and in the Canadian province of Alberta.(Reuters: Greg Funston/University of Edinburgh)

Scientists for the first time have found embryonic remains from a group of ferocious meat-eating dinosaurs that includes the Tyrannosaurus rex.

They found fossilised jaw and claw bones that show these record-size babies looked a lot like adults and were "born ready" to hunt.

The fossils, the researchers said, represented two species from the tyrannosaurs group, the apex predators in Asia and North America during the Cretaceous Period toward the end of the dinosaur age.

The bones indicated these were bigger than any other known dinosaur babies — 1 metre long, or the size of a medium dog — and hatched from what must have been enormous eggs, perhaps exceeding the 43-centimetres in length of the largest dinosaur eggs currently known.

University of Edinburgh palaeontologist Greg Funston, lead author of the research published in the Canadian Journal of Earth Sciences, said the scientists were amazed at how similar the embryonic bones were to older juvenile and adult tyrannosaurs.

He also noted that the jaws boasted functional teeth.

"So although we can't get a complete picture, what we can see looks very similar to the adults," Mr Funston said.

He added it appears that tyrannosaurs were "already possessing some of the key adaptations that gave tyrannosaurs their powerful bites".

"So it's likely that they were capable of hunting fairly quickly after birth, but we need more fossils to tell exactly how fast that was," he said.

The roughly 77 million-year-old jawbone, about 3 centimetres in length, was unearthed in the US state of Montana, and may belong to a species called Daspletosaurus.

The roughly 72 million-year-old wedge-shaped claw came from Canada's Alberta province and may belong to a species called Albertosaurus.

Both are slightly smaller cousins of Tyrannosaurus rex. The largest-known tyrannosaurs topped 12 meters-long and 8 tonnes in weight.

However, the jaw possesses distinctive tyrannosaur traits, including a deep groove inside and a prominent chin.

Reuters

 

 

 

Winton dinosaur field reveals biggest carnivorous dinosaur ever found in Australia

 

An artist's impression of Australovenator preparing to eat its prey.(Travis Tischler)

Bones from the largest theropod dinosaur ever discovered in Australia have been uncovered in western Queensland.

Key points:

• Theropods could be up to 2 metres high and 7 metres long
• The latest discovery closely resembles a species found nearby in 2006
• It had large hands with what Dr White called "recurved claws"

They were initially uncovered in 2017 at the now world-famous dinosaur fossil field in Winton, but were only recently identified as most likely belonging to the Australovenator wintonensis species, discovered in 2006.

Lead researcher Dr Matt White from the University of New England said when the bones were first uncovered "they didn't look like much at all".

"We had a really good look through all of the fragments and that's when I got quite excited because we started to find the distal elements of bones that resembled a theropod, which are extremely rare," he said.

Theropods are a large group of bipedal and largely carnivorous dinosaurs, including the Velociraptor and Tyrannosaurus rex.

The bones cannot be definitively identified to a species, but closely resemble an Australovenator wintonensis specimen found less than 2 kilometres away in 2006.

Dr White said the dinosaurs could be up to 2 metres high, between 5 to 7 metres long, and were similar in appearance to the velociraptors depicted in the film Jurassic Park.

"Except the claws are on the hands, not the feet," he said.

"It had quite large hands, but on each hand it had two recurved claws that were quite large … and like birds you have a horny sheath over the top so they would have ended up round about close to 25 to 30 centimetres."

Hunter or scavenger?

Dr White said while it was hard to determine a dinosaur's hunting behaviour based on its skeleton, Australovenator was probably some kind of predator.

He said it had two claws on each hand "used for grappling prey".

Dr White said they may also have done some scavenging.

"If they've got an easy feed, they probably would have had an easy feed."

He said there were almost certainly many of them hunting the same prey.

"Given the amount of teeth we've found [it is] probably not just one feasting on a carcass, it would have been two or three."

Dr White said sauropods — long-necked, quadrupedal herbivores — were almost certainly Australovenator's main prey.

"Every sauropod site that we have dug in over the years, we find these isolated shed teeth," he said.

"We haven't really found teeth that are much bigger than Australovenator, so these things would have been the top carnivore.

"We just haven't found any other evidence of anything larger than these guys, Australia-wide."

Did dinosaurs have feathers?

Dr White said whether this group of dinosaurs had feathers was still hotly debated among members of the scientific community.

"There's two major groups [of theropods] — you've got your more primitive Tetanurans where Allosaurus is, and then have your Coelurosaurs where you have Tyrannosaurus."

He said the Tyrannosaurus was a member of the group that probably had feathers.

"I suspect it is within the more primitive group, but it is still heavily debated."

Dr White said this was one of the reasons each new dinosaur find was important, because it brought scientists closer to answering such questions.

"We can start to work out, well — did they have feathers? Which group they sat in, and unfortunately the preservation out at Winton is not good enough to preserve feathers."

The newly identified theropod bones are on display at the Australian Age of Dinosaurs Museum near Winton.

 Australoventors fed on larger herbivores.(Travis Tischler)

Murusraptor

By Gemma Tarlach

Sexy Beast of the Week: Murusraptor barrosaensis, the newest member of the megaraptor gang. The Patagonian predator of 80 million years ago was larger but had a more fine-boned build than other megaraptorids. Credit: Jan Sovak. Want to find some awesome dinosaur species new to science? Head south. South America is clearly the place to be these days, with Patagonian predator Murusraptor barrosaensis the latest intriguingly odd animal to stomp onto the paleoscene. Like fellow Argentine Gualicho shinyae, announced last week, Murusraptor is known from the partial skeleton of a single specimen. And while Gualicho made headlines for its shorty-short forelimbs, Murusraptor is like those models in perfume ads: a leggy mystery that's got people intrigued.

Murusraptor is a large, slender megaraptorid. You may read "raptor" and think oh, velociraptor*, bitey bitey, clever girl, but, while megaraptorids did have big ol' claws, they're not closely related to the stars of the Jurassic Park movies. (*Yes, I know Hollywood's idea of a velociraptor is, shall we say, just a bit outsized when compared with the fossil record, but let's not have that discussion right here and right now, 'k?) Megaraptorids were a group of carnivorous dinosaurs from the Cretaceous that, in addition to those claws, had some sweet pneumatization action going on. A number of their bones were essentially hollow, or at least partly so, full of air pockets. Murusaptor is notably, shall we say, aerated. It's a trait also seen in most modern birds and some other dinosaurs, particularly those most closely related to birds. (Don't feel too left out, puny human: those sinus cavities of yours, currently all stuffed up from summer allergies, are another example of pneumatization.) Airy bones are one reason paleontologists have found it challenging to determine where megaraptorids sit in the family tree of theropods, a diverse bunch of mostly carnivorous, bipedal dinosaurs spanning more than 230 million years, from the earliest dinos to that chicken you're eating for dinner. Within Theropoda, the megaraptorids have variously been classified as allosaurid, coelurosaurid and, more specifically within the coelurosaurs, as tyrannosaurids. Without getting too deep into the -id of it all, megaraptors are all over the map in terms of how they might be related to other dinosaurs. More on that in a bit. Murusraptor presented additional opportunities for head-scratching. Even the authors of the first paper on the animal, published today in the open-access journal PLOS One, weren't sure what they'd dug up.

Co-author Philip Currie of the University of Alberta, one of the world's leading paleontologists, admits Murusraptor initially had him stumped. Sending a quick email as he headed back into the field, Currie shared the team's process of figuring out what they had on their hands: "The animal completely puzzled us when we found it because it is an animal as large as a tyrannosaur like Albertosaurus [about 30 feet long], but was as pneumatic as an oviraptorosaur [a very bird-like bunch of dinos]...." Currie went on to explain that the dinosaur had other traits that might have placed it as a primitive, or basal, maniraptor (the line which eventually led to birds) or even a spinosaurid, a particularly whacky group of crocodilian-skulled dinosaurs that includes the largest predatory dinosaur ever known.

The fossilized bones of Murusraptor found by the team and shown here in white include much of the rear cranium. The braincase in particular is well-preserved and allowed researchers to determine the animal was not fully mature at time of death. Credit: Coria et al (2016) Only after all the fossils of the specimen — unearthed more than a decade ago — were prepped and analyzed did the team feel comfortable assigning Murusraptor to the megaraptor group. Currie and lead author Rodolfo Coria, another megafigure in paleontology, used the new data gleaned from analyzing Murusraptor to see if it would help them answer, once and for all, where on the family tree megaraptorids belonged. Spoiler alert: it didn't. When they compared specific traits of megaraptorids, including Murusraptor, with those of other dinosaurs, slight tweaks to the modeling process yielded two very different results. In other words, the jury is still out on whether these animals are allosaurids or tyrannosaurids.

While we're still not sure where Murusraptor and the other megaraptorids fit in the dinosaur evolution story, this specimen is exciting because it includes a fair chunk of the cranium. In particular, the braincase is beautifully preserved. In fact, it was in such great shape that the team was able to see signs of infection on the left side of the skull — no word on whether the boo-boo was responsible for the animal's death, however. Believed to be just over 21 feet long, the Murusraptor specimen was a juvenile — researchers were able to determine that because the bones of the rear skull, while knitted together as in adults, still showed their seams. That's a tip-off that the animal had not yet reached full maturity. Look for more news about that gorgeous braincase soon. For now, initial analysis of the cranium suggests Murusraptor may have had a crest on the top of its head. Show-off.

Murusraptor and last week's dino-breakout Gualicho were found in the same large basin in west-central Argentina, an area centered around the small city of Plaza Huincul. The animals were separated by millions of years, however: Murusraptor is about 80 million years old, while Gualicho is 10-14 million years older. The animals also represent different branches of the theropod family tree. They're just the latest pair of predators to emerge from the neighborhood, in addition to a number of other dinosaurs and other extinct animals discovered there. "Off the top of my head I would guess that the sites are within a hundred kilometers of each other," notes Currie. "This area (about 200 km radius around Plaza Huincul) is definitely the hot spot for dinosaurs in South America."

African Dinosaur Spinosaurus

Fossil discovery proves massive African dinosaur Spinosaurus was actually a semi-aquatic 'river monster'

Newly discovered bones from the huge African predator Spinosaurus prove it could swim, scientists say, and that the existence of this "river monster" shows some non-bird dinosaurs invaded the aquatic realm.

Scientists this week announced the discovery of fossil bones from the tail of ​Spinosaurus ("spine lizard"), found in south-east Morocco, which they said provided a deeper understanding of the appearance, lifestyle and capabilities of the longest meat-eating dinosaur on record.

"Spinosaurus had a highly specialised tail — a propulsive structure that would have allowed this river monster to actively pursue prey in the water column," University of Detroit Mercy palaeontologist and anatomist Nizar Ibrahim, lead author of the study published in the journal Nature, said.

Spinosaurus, which lived 95 million years ago during the Cretaceous Period, was a highly unusual dinosaur and not just because of its staggering dimensions of up to 15 meters long and more than 6,000 kilograms.

The anatomy of Spinosaurus had remained mysterious for decades after crucial fossils were destroyed during World War II, until the 2008 discovery of the Morocco skeleton. Extraction of these additional tail bones has been ongoing since 2015.

Its tail was flexible, with a large surface area thanks to a series of tall neural spines — different from the stiff and tapering tails of other carnivorous dinosaurs like Tyrannosaurus rex — indicating Spinosaurus and its close relatives engaged in tail-propelled locomotion unlike any other dinosaurs.

Laboratory experiments in which a plastic model of the Spinosaurus tail was attached to a robotic swimming device showed that the tail could move laterally to create thrust and power the animal through water like a crocodile, according to Harvard University fish biologist and biomechanist George Lauder, a study co-author.

This indicates Spinosaurus terrorised rivers and river banks as a semi-aquatic animal, not merely wading into the water waiting for fish to swim by. It may have eaten huge fish, including sharks.

"This discovery overturns decades-old ideas that non-bird dinosaurs were restricted to terrestrial environments," Harvard University vertebrate palaeontologist and biomechanist Stephanie Pierce, another study co-author, said.

    "So, yes, we believe that this discovery does indeed revolutionise our understanding of dinosaur biology."

Spinosaurus still was able to move on land and lay eggs there, perhaps walking on four legs rather than two like other meat-eating dinosaurs.

"But it had so many adaptations to an aquatic existence — nostrils high on the skull and further back from the tip, flat-bottomed toe bones and claws, dense and thickened bone for buoyancy control, and this newly discovered tail form — that it would have been at least as aquatic as Nile Crocodiles," University of Portsmouth palaeontologist and study co-author David Martill said.

Ms Pierce said it "just might topple T-rex as the most famous and exciting meat-eating dinosaur".