A nondescript 115-million-year-old fragment of leg bone has yielded spectacularly preserved red blood cells, which may be the earliest ever found in dinosaurs.

Red blood cells have previously been found in dinosaur remains, including 75-million-year-old bone fragments collected in Canada in 2015 and the femur of a Tyrannosaurus rex that died 68 million years ago, found in Montana in 2005.

Now, at Curtin University in Perth, Australia, and her colleagues say they have isolated the oldest-ever dinosaur red blood cells from the hind-limb of a theropod dinosaur, Aratasaurus museunacionali, found in Brazil in 2008.

The Aratasaurus individual studied by the team wasn’t yet fully grown, with an estimated body length of just over 3 metres, and weighed about 34 kilograms.

“The fossils we worked on are not display specimens by any means, so they don’t look very interesting,” says Grice. ���� you look at them, you think there’s just a bunch of bones and there’s probably not much in there.”

Grice cut thin sections of bone, mounted them onto glass slides and used hydrochloric acid to remove surrounding rock – and she was shocked at what she saw.

“I was jumping up and down,” says Grice. “I ran up to my head of school’s office and was so excited that he gave me a whisky to calm me down. No one has ever seen dinosaur red blood cells in high resolution before.”

The cells she found were abundant: in a single slide, just a fifth of a millimetre wide, there were 20 blood cells. All of the cells were within fossilised blood vessels, providing further evidence that they really were red blood cells.

Liquid chromatography–mass spectrometry analysis revealed the presence of haem B, a constituent of haemoglobin that binds to oxygen, adding molecular evidence of the type of cell.

The team also had to rule out the possibility of any contamination, especially from the sediments in which the fossil was preserved, which were dominated by algae.

The cells found outside the bone were dominated by chlorophyll-derived compounds, whereas those inside contained haem-derived molecules, which strongly suggests that the latter cells weren’t a result of contamination.

The researchers also compared the blood cells to those of the closest living relatives of the dinosaur fossil, birds and crocodiles. The Aratasaurus red blood cells are significantly larger. This could indicate that the cells swelled during fossilisation, or that the species grew much bigger than the fossilised specimen.

at the Natural History Museum in London says previous studies reporting red blood cells in fossils tens of millions of years old are contentious, with some researchers suggesting they could be the result of bacteria or artefacts of the fossilisation process. “This paper is further evidence that fossilised soft tissues such as red blood cells can preserve over geological timescales,” she says.

Grice says the discovery may mean that other nondescript dinosaur fossils that have been locked away in museum collections may hold profound secrets. “There’s drawers and drawers of fossil material, which don’t look very nice,” she says. “This kind of work opens up a whole new opportunity to unlock those collections and bring modern technology and molecular techniques to these specimens.”

Meet Invictibellatrix amberina, the unconquered female warrior – a new species of predatory dinosaur related to Tyrannosaurus rex that hails from the Isle of Wight in southern England.

The fossil used to identify it – a partial braincase – has been lying in the archives of the Natural History Museum in London since it was acquired from a Reverend Reginald Hooley in 1924. “It was sitting unstudied in the museum for about 100 years, which is very surreal,” says , now at the University of Leeds, UK.

Morrison and his colleagues used CT scans to create a 3D scan of the fossil and compared it with features of other dinosaurs.

The closest match was the Argentinian megaraptoran from about 80 million years ago. So, the researchers suggest that the skull, originally found in 120-million-year-old rocks from the Lower Cretaceous Wessex Formation on the south-west coast of the Isle of Wight, is from a new species belonging to the Megaraptora group of carnivorous dinosaurs. If so, it is the first time a megaraptoran has been discovered in Europe.

A similar-looking dinosaur is known from a few million years earlier in the Wessex Formation: the 5-metre-long . However, the parts we have hint that it belonged to the sister group of tyrannosaurs and none of the fossilised remains of the two individuals directly overlap, so it is hard to compare them.

The genus name Morrison and his colleagues have given to the newly described fossil, Invictibellatrix, means female unconquered warrior. They estimate that it was an agile, two-legged carnivore that was about 3 to 4 metres long, some 1.5 metres tall and weighing between 200 and 300 kilograms. It is likely to have had feathers and claws 10 to 20 centimetres long for attacking small dinosaurs, lizards and mammals, says Morrison.

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Had we been around then, “humans would have been perfect-sized prey, about a third of their body weight,” he says.

At the time, the Isle of Wight was still firmly attached to both mainland Britain and the rest of Europe, and the environment would have been subtropical, says Morrison.

Megaraptoran fossils have been found in Asia, Australia and South America, and finding one in Europe would begin to tie their story together.

Morrison suggests that Invictibellatrix evolved from Asian megaraptorans that dispersed into Europe some 130 million years ago. Then megaraptorans spread from Europe to Africa, then to South America and Australia before the continents completely separated.

at Monash University in Melbourne says it is a shame more detailed comparisons couldn’t be made with Eotyrannus, which has previously been considered a relative of megaraptorans.

���� Invictibellatrix is indeed a megaraptoran, it expands the palaeobiogeographic range of the group and plugs a significant gap in our knowledge, linking those from South-East Asia to Australia and South America via Europe and Africa,” he says. “However, more fossils are required to support or reject this hypothesis.”

The world’s most famous dinosaur, Tyrannosaurus rex, was probably warm-blooded like birds and mammals, new evidence, obtained from 66-million-year-old tooth enamel, suggests, adding weight to previous findings.

at South Carolina State Museum, who wasn’t involved in the new study, says the research means “the opening to the last Jurassic World flick was one big pile of Hollywood bunk”.

“That film premised that dinosaurs could not survive in the modern world, except near the equator,” says Persons. “Not so. The evidence indicates that a Tyrannosaurus would be comfortable in subtropical and even mild climates.”

at the University of California, Los Angeles, and his colleagues analysed the chemistry in the enamel of three T. rex teeth and compared them with five similarly aged fossilised crocodile teeth.

The researchers also compared their results with data from mammals such as elephants and mammoths to try to determine whether T. rex was also an endotherm – an animal that can regulate its body heat through its metabolism. Ectothermic, or so-called cold-blooded animals like crocodiles, often warm up by basking in the sun instead.

Endothermy is common in large animals and even some fish, says Eagle, allowing them to move around and exhibit more sustained activity to find food and migrate, and to live in colder environments. It has long been thought that many dinosaurs, including T. rex, were also warm-blooded.

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“It comes at a cost though – higher metabolic rates mean higher food requirements and potentially more active hunting to acquire it,” he says.

Within the enamel chemistry, the researchers focused on the abundance of bonds between rare heavy isotopes of carbon and oxygen, known as carbon-13-oxygen-18 bonds. These bonds are more abundant in minerals that form at cold temperatures than minerals that form at warm temperatures.

“Therefore, in a very old tooth we can measure carbon-13-oxygen-18 bond abundance and figure out whether it formed in a hot or cold body.”

He says T. rex had a body temperature of around 36°C, similar to large modern mammals but below many modern birds.

“We also found that the reconstructed temperature of T. rex was significantly elevated compared to temperatures derived from crocodile teeth from the same geological formation – Hell Creek in Montana,” Eagle says.

The researchers also say that T. rex body temperatures were higher than the ambient temperatures in prehistoric Montana, reconstructed both from isotopic estimates and climate models.

“Using thermal performance curves and climate modelling based on these results, we found that the entire North American continent would have been habitable for T. rex in the Cretaceous Period,” he says.

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Persons says there was already extensive evidence that T. rex was warm-blooded, including bone growth rates and predator-prey ratios – with energy-hungry endotherms than ectotherms – and a “slew of anatomical traits consistent with high-performance athleticism”.

at Carthage College in Wisconsin says the new work is an “example of science in action, converging upon a single, robust hypothesis, which in this case reveals T. rex as an active top predator”.

The researchers “make the case for a wide geographic distribution for T. rex, showing that it could tolerate cool temperatures in the north of its range and tolerate the tropical temperatures in the south”, says Carr. “And in both cases, T. rex‘s body temperature is higher than the average air temperature. That result is consistent with the hypothesis that T. rex might have migrated from Asia into North America at high latitudes.”

A bird that was eaten and partially excreted by a dinosaur 66 million years ago has left behind the best-preserved feathers ever recovered by scientists from dinosaur-age rock. This pushes the evolution of feathers, like the ones on modern birds, back by 10 million years and may tell us more about why most birds didn’t survive the post-asteroid mass extinction.

“This is the best feather we’ve ever seen in a Mesozoic [252 million to 66 million years ago] deposit,” says at the Field Museum in Chicago. “[It’s] like a feather you could pick up off the ground.”

Birds were the only dinosaurs to survive the mass extinction triggered by an asteroid strike 66 million years ago. But, puzzlingly, only one branch made it through: neornithes, the ancestors of every bird alive today.

In 2016, at the University of Washington in Seattle was collecting fish fossils in north-eastern Montana’s Hell Creek Formation when he discovered a broken coprolite, a fossilised dropping, with a feather clearly visible along its fractured surface. “I couldn’t believe what I was seeing,” he says.

A few years later, he invited O’Connor to team up with him and his colleagues to analyse the coprolite using micro-CT scans and 3D surface scanning. Two leg-bone fragments, 18 and 12 millimetres long, resembled some previously found at Hell Creek and attributed to hesperornithiformes. These were flightless, short-winged diving birds, similar to modern loons (Gaviiformes) or grebes (Podicipediformes), and were related to Neornithes.

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Further analyses showed that the 9.3-millimetre-long primary feather had a water-repellent structure, similar to that of modern pelicans, says O’Connor. Both this and a second, smaller wing feather also had lightweight, spongy cores surrounded by a harder outer layer. This combination makes them both light and stiff, which is typical of modern feathers.

“What is exciting is to push the occurrence of modern feathers into non-modern birds,” says O’Connor. Differences in plumage are emerging as a major contributing factor as to why some birds survived while others didn’t, she says.

The team also found two fluffy body feathers with loosely arranged branches, echoing in a lineage that didn’t survive the extinction event.

Combined, this suggests that the bird the feather belonged to – and hesperornithiformes in general – had a “middle ground” of primitive and modern plumage, says O’Connor. While the wing and tail feathers might have allowed for successful diving, for example, the less advanced body feathers would have been relatively poor insulators, making the animals more vulnerable to the “winter” that occurred after the asteroid impact.

“These are the feathers that are responsible for keeping the body warm, right?” says O’Connor. “So maybe these primitive feathers were good enough to keep them warm during the greenhouse world of the Mesozoic, but not good enough to keep them warm during this environmental catastrophe that was triggered by this impact event.”

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The dropping – which probably came from a Nanotyrannus or a young Tyrannosaurus rex – also contained two rigid, diamond-shaped scales, 3 to 4 millimetres long. The researchers think this came from a gar (Lepisosteidae), a narrow-bodied fish that still exists today. This would have been too small for the dinosaur predator and thus was probably eaten by the bird.

“This discovery is really exciting,” says at the University of Connecticut. “It opens up so many questions about how feathers evolved, what they were originally used for, and how they came to perform so many different functions in modern birds.”

The links among the different animals involved are also fascinating, says Muzio. “Discoveries like this really make the imagination run wild,” he says. “From a single coprolite, we are learning about at least three individual species – morphologically, ecologically and evolutionarily. What more can you ask for?”

Dinosaurs are the biggest creatures to have ever walked on land, dominating Earth for over 130 million years. But how could such extraordinary creatures have simply vanished in the blink of a geological eye? For decades, we’ve assumed these prehistoric megafauna – a staple of our childhoods and Hollywood movies – went extinct for one simple reason: the asteroid that hit Earth was so unimaginably large that it changed everything in one single blow. But now, thanks to new research, an even more intriguing idea has emerged: size alone doesn’t explain what happened.

The real reason the impact was so devastating may have been its angle. Had the asteroid arrived a little steeper, the outcome might have been different. A little shallower, different again. And for life on Earth at the time, predominantly dinosaurs on land, marine creatures in the sea and pterosaurs in the air, it appears to have struck at almost the worst possible angle imaginable, launching vast quantities of rock, dust and climate-altering gases high into the atmosphere and triggering one of the greatest mass extinctions in Earth’s history.

With jaws like these, who needs big arms? A new analysis suggests dinosaurs like Tyrannosaurus rex had shrunken forelimbs because their massive, powerful heads became their primary tool for killing large prey, rendering their arms redundant. It is an evolutionary approach that five different lineages of large theropod dinosaurs took independently.

Researchers are well aware that a number of large, predatory theropods followed a trend towards bigger bodies, bigger heads and smaller, shorter arms over time. But it wasn’t known why this pattern repeated across multiple predatory dinosaur families, scattered across the globe and separated by many millions of years, says at University College London. There was also little understanding of how the bones in their ever-heftier skulls changed as their arms became proportionally smaller.

“This paper tackles one of the big evolutionary questions in theropod dinosaurs,” says at the University of Bristol, UK, who wasn’t involved with the research.

Scherer and his colleagues compiled data on the proportions of the forelimbs and skulls of 85 theropod species, along with body-mass data. This allowed them to calculate a ratio between the skull dimensions and forelimb lengths, quantifying just how small the arms were compared with the head. The researchers then compared this ratio with other measurements of the dinosaurs’ bodies, along with a measure of the skulls’ strength based on factors such as bite force and skull rigidity.

The team found that skull durability was associated with smaller arms, regardless of where the species sat in the theropod evolutionary tree. ���� it’s a predatory theropod and has a very robust skull, it will most likely have relatively small forelimbs,” says Scherer.

The researchers found this head-arm divergence evolved independently in five theropod groups: tyrannosaurids, the short-snouted abelisaurids, the knife-toothed carcharodontosaurids, ceratosaurids and megalosaurids. This evolutionary pattern hadn’t been identified in the last two groups until this study, points out at the Beipiao Pterosaur Museum of China, who wasn’t involved in the research. This shows how hidden evolutionary signals can be revealed when traits are quantified in this way, she says.

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The findings provide clues as to why the dinosaurs’ arms kept shrinking. These predators’ increasing skull strength and body size coincided with the rising mass of their quarries. The theropods evolved huge, sturdy skulls for subduing their large, difficult-to-control prey. Their heads were clearly doing the majority of the work, says Scherer, reducing the need for strong, grappling arms.

“Nature doesn’t like to have everything all at once,” he says. A big, powerful head plus strong forelimbs would require a lot of energy to maintain.

This creates a trade-off between jaws and claws. Other theropods like the megaraptorans and spinosaurs were also very large predators, but they took the opposite route to dinosaurs like T. rex, coupling long arms with slender skulls.

Rowe is curious about the mechanical function of the jaw-centric theropods’ arms, even in their shortened state. “Yes, tyrannosaurs had tiny, vestigial arms, but that does not necessarily mean they were completely useless,” he says.

He adds that the study emphasises the evolutionary diversity of dinosaurs. “It reminds me of why I fell in love with dinosaurs in the first place,” he says. “They were some of the most innovative and successful animals to ever exist.”

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HOW could we talk about David Attenborough’s best documentaries without featuring the photo perhaps most associated with the broadcaster, whose 100th birthday is on 8 May?

Life on Earth, the groundbreaking 1979 series containing that iconic gorilla sequence, pictured above, introduced a wider audience to the calm narration and stunning nature shots for which Attenborough is known today. His many documentaries would go on to move from the ocean depths to the lives of plants, and from the distant past to the fight against climate change.

Read on to discover which made the biggest impact on our staff, and which they deem worth watching today.

(1979)

Life on Earth is special to me for so many reasons. There is that famous encounter with gorillas. It was also the first ambitious nature series of its kind – without its success, we might never have had the many great series that followed it. Then there’s the brilliant way Attenborough tells the story of deep time as he descends the Grand Canyon, and then back up again. There’s probably as much science here as in the rest of his programmes put together – I don’t think I’ve seen a better TV series on the evolution of life. OK, from today’s perspective it is a bit lectury at times, but who would you rather be lectured by?

Last but not least, for me, it has personal meaning, as I’m sure it does for many other people who saw it in their youth and were influenced by it. That wonky opening music by Edward Williams is just so evocative.

Michael Le Page, reporter

(1995)

Plants live on another plane of existence. Every morning, drooping wood anemones lift their heads and nod at the sun, while brambles grapple across the forest floor with slow aggression. Exploding pods launch seeds in a millisecond; on mountain tops, bristlecone pines gnarl into stumps over thousands of years.

Time-lapse and high-speed photography weren’t new when The Private Life of Plants was filmed, but this was the first series to use them at scale. They allowed Attenborough to explore the agency and the intelligence of flora like never before.

When I rewatch the series today, the lurid colour grade, bespoke plant-themed typeface and rudimentary CGI bring me as much joy as the plants’ private lives. I would also recommend the behind-the-scenes for the plants of Life, which lays bare the painstaking ingenuity of the film-makers who capture these other worlds.

Thomas Lewton, features editor

(2001)

As the first in-depth look at what is happening beneath the rarely explored waves, The Blue Planet astounded me when I first watched it. New species were discovered and extraordinary footage showed blue whales from the air, alien-looking creatures in the ocean depths and, most surprisingly, herring sperm as far as the eye could see.

I am still haunted 25 years later by watching a pod of orcas spend 6 hours hunting a grey whale calf to eat only its lower jaw and tongue. Attenborough’s narration is calm, clear and concise, unafraid to let the images and music hold our attention.

It may not have the glossy HD footage or drone shots of more recent series, but it changed the shape of nature documentaries.

It also blew my mind and sparked a life-long interest in the oceans. Without it, I wouldn’t have ended up at New Scientist!

Eleanor Parsons, magazine editor

(2006)

Those nighttime images of a massive pride of lions swarming over a fleeing young elephant have stayed with me ever since the first series was shown in 2006. The film-makers set out to create a spectacular, high-definition series, and boy did they achieve it.

The many notable moments in Planet Earth include a starving polar bear trying to catch walruses, eagles preying on cranes as they fly over the Himalayas, dolphins beaching themselves to hunt fish and bears climbing mountains to feast on moths. This is simply incredible television. Watch it now if you haven’t seen it. Watch it again if you have.

The second series, first shown in 2016, also made a notable departure. While Attenborough’s previous series all showed wildlife in pristine wildernesses, the last episode here, and in the third series (2023), is about animals living alongside people, from leopards and monkeys to falcons and otters.

I do think Attenborough has been right to aim to evoke wonder rather than despair in most of his programmes, but now there’s no denying we live on a much-changed planet.

Michael Le Page, reporter

(2011)

Wondrous and strange is the life that thrives at the very ends of Earth. Frozen Planet cast a loving eye over the inhabitants of the Arctic and Antarctica, hostile lands whose charms are apparent from the earliest moments of this excellent series. The narrative bounces back and forth from one pole to the other, treating us to scheming penguins, swimming snails, polar bears and a bison charging down wolves.

Among it all, the then 84-year-old David Attenborough, bundled up in a fetching array of parkas, makes the odd appearance as our all-terrain guide to these alien environments.

Casting a pall over proceedings, of course, were the advancing effects of climate change. The series’ seventh episode, “On Thin Ice”, was an explicit call for the world to do more to protect these magnificent ecosystems and those living in them, including humans.

The magic of Frozen Planet wasn’t just that it told us how global warming imperils the poles, it’s that it made us truly care about what we might be losing.

Bethan Ackerley, subeditor

(2020)

Like an ice core or tree ring, David Attenborough’s long and extraordinary life has come to be used as a yardstick for change. Socially, technologically and environmentally, the world of his youth was a far cry from the one we see today – and in this powerful film, Attenborough charts how we have degraded Earth’s ecosystems over his lifetime.

Released during the first year of the covid-19 pandemic, A Life on Our Planet was a timely warning from a man who has seen more of Earth’s wonders – like this turtle, pictured swimming over a coral reef – than perhaps anyone else alive. Its marriage of the personal and the political makes it a different beast from most Attenborough films. Climate change, biodiversity loss and rampant pollution all feature, as Attenborough sets out what a child born in 2020 may witness over their lifetime. It makes for bleak viewing, but, as is a hallmark of more recent Attenborough works, it also supplies plenty of solutions to the environmental crises we’re living through – if we’d only apply them.

Bethan Ackerley, subeditor

(2022)

Prehistoric Planet is far from the first programme to try to bring long-extinct animals back to life on the small screen, but it is the best so far. Of course, the programme-makers had to use their imagination to some extent, but the series has been praised by palaeontologists for its accuracy and naturalism.

The three series feature many of the most iconic animals of the past, but shows them in new ways – we see Tyrannosaurus rex swimming and mating, for instance. There are lots of smaller, lesser-known animals, too. For me, the real stars are not the dinosaurs but the pterosaurs, brought back to life in stunning detail.

The third series jumps forward in time to the recent glacial periods, featuring animals such as mammoths, sabre-toothed cats and many more. The content is just as brilliant, but Tom Hiddleston replaces David Attenborough as the narrator. It’s just not the same without him.

Michael Le Page, reporter

(2026)

This very late entry to the David Attenborough canon became an instant classic in my household, since it was shown on New Year’s Day. We’ve rewatched the extraordinary exploits of London’s wildlife many times.

Yes, this one-off urban showcase has the foxes and pigeons you would expect, but not as you would expect to see them: vixens viciously squaring off on the streets of Tottenham and pigeons intelligently commuting on the tube from Hammersmith are standout moments.

But the bigger surprises come from how much the city’s nature has changed in recent decades. Peregrine falcons now soar over the centre, ring-necked parakeets have conquered the parks, Aesculapian snakes dangle from the trees along the Regent’s Canal and, since covid lockdowns, large numbers of fallow deer have taken to roaming parts of Romford.

The programme tours a London that is familiar to locals but rarely seen on screen: the community gardens, cemeteries and suburban parks that make the city an outstanding place to live, even for the nature-lovers who sometimes wonder if a megacity is the right place for them.

Perhaps their lingering doubt will be extinguished by Attenborough’s own assertion that he wouldn’t want to live anywhere else.

Penny Sarchet, managing editor