Dinosaurs got extinct, how about dinosaur age plants?


This video says about itself:

The Day The Mesozoic Died HD

30 May 2013

The disappearance of the dinosaurs at the end of the Cretaceous period posed one of the greatest, long-standing scientific mysteries. This three-act film tells the story of the extraordinary detective work that solved it. Shot on location in Italy, Spain, Texas, Colorado, and North Dakota, the film traces the uncovering of key clues that led to the stunning discovery that an asteroid struck the Earth 66 million years ago, triggering a mass extinction of animals, plants, and even microorganisms. Each act illustrates the nature and power of the scientific method. Representing a rare instance in which many different disciplines—geology, physics, biology, chemistry, paleontology—contributed to a revolutionary theory, the film is intended for students in all science classes.

From Laelaps blog today:

Planting the Cenozoic Garden

by Brian Switek

Sixty six million years ago, a global catastrophe extinguished the non-avian dinosaurs. This is common knowledge. It’s also too narrow a view. Various forms of life disappeared in the same geologic instant – from coil-shelled ammonites to some forms of mammal – and others, for reasons as yet unknown, survived.

Plants are among the neglected of the victims and survivors. A magnolia tree does not hold the same cultural cachet as Tyrannosaurus. The post-impact “fern spike” is often cited as a symbol of wide-ranging devastation, but, outside technical journals, that’s about the extent of our attention span for paleoflora. That’s a shame. If we’re going to understand how life on Earth was so deeply wounded 66 million years ago, and how it bounced back, we should be looking more closely at the prehistoric garden.

Hot on the heels of a review summarizing the global dinosaurian picture at the end of the Cretaceous, Lund University paleobotanists Vivi Vajda and Antoine Bercovici have now assembled a view of how plants were affected by the Earth’s fifth mass extinction. Prehistoric pollen and spores tell the story.

The advantage of looking at fossil pollen, Vajda and Bercovici write, is that there’s plenty of it. That’s not only because plants produce large amounts of the reproductive material, but because pollen is also incredibly durable. If you want to see who’s living where, and how environments change through time, these microscopic plant fossils are good way to do it.

In some ways, the story of the Cretaceous plants echoes what paleontologists have found among other forms of life. The Cretaceous world was a highly-dynamic one marked by fluctuating sea levels, the further breakup of continents, and the formation of new mountain ranges. All this moving and shuffling created evolutionary pockets where new species could evolve in relative isolation, becoming restricted to their particular province. Plants proliferated and evolved according to these boundaries just as dinosaurs did.

Each of the pollen provinces, outlined by Vajda and Bercovici, have their own distinctive profile. In northern North America, Asia, and a few spots in South America, Late Cretaceous sediments commonly contain Aquilapollenites – pollen thought to have come from a group of plants closely related to the modern sandalwood. A neighboring province – stretching from eastern North America to the Himalayas – is dominated by pollen from a Cretaceous birch relative, while rocks from the same time in northern South America, central Africa, and India are rife with pollen from palms. Rounding out the set, a southern hemisphere swath has plenty of pollen from plants related to southern beeches and shrubs.

These were not the only plants to exist in those areas, of course, but their pollen broadly delineates differentiated patches. Paleobotanists can zoom in from there, and, as with dinosaurs, the best-studied sites on the planet document the end of the Cretaceous through the beginning of the Paleogene in western North America.

The forests that Tyrannosaurus and Triceratops knew were dominated by angiosperms – flowering plants – with some conifers, ferns, ginkgos, and cycads for good measure. Palm trees stood alongside evergreens and towered above a shrubby understory in these Late Cretaceous forests. In the aftermath of the impact 66 million years ago, however, those forests were replaced by a relatively small collection of angiosperms, a shadow of the diversity that the Edmontosaurus and kin knew.

Plants suffered extinctions just as many other forms of life did. In fact, some of them dwindle to nothing right at the K-Pg boundary are called “K-species” or “K-taxa.” In the pollen record of North America, for example, the sandalwood relative and a suite of species in seven other genera give way to species in just two genera. Overall, about 60% of plant species present in Cretaceous North America went extinct. The rest of the globe reflects a similar pattern, albeit with different species. Many pollen-producing plants either went entirely extinct or became much less abundant.

Clues from the earliest days of the Paleogene track how plant life eventually bounced back. While sites in New Zealand preserve a “fungal spike” from when mushrooms and their ilk thrived on decomposing matter under blacked-out skies, the subsequent “fern spike” records when pioneering plants – primarily ferns – quickly spread as sunlight began to return. The angiosperms, as well as some conifers, followed, but with fewer species than before. Depending on the location, plant life took between one and ten million years to recover to pre-extinction levels of diversity.

As with the animals, though, why some plants went extinct and others persisted is a mystery. Perhaps some were simply lucky enough to grow in places that were less affected by the devastation following the asteroid strike. Then again, Vajda and Bercovici point out, some researchers have suggested that plants carrying additional sets of chromosomes – or were polyploid – might have had the genetic flexibility to more quickly adapt after ecological shock.

Discerning what made a survivor isn’t just an exercise in replaying ancient history, though.

Vajda and Bercovici argue that two previous mass extinctions – roughly 251 and 200 million years ago – follow a similar pattern of a highly-diverse flora being pruned back, followed by crisis species, pioneer communities, and ecosystem recovery in sequence. Which left me to wonder if we’re going to see this pattern again. If  we’re not yet in a Sixth Extinction, we’re close, and identifying likely survivors verses vulnerable species is an essential part of conservation triage. By sifting through the past, down to the tiniest pollen grain, we can reflect on what sort of future we want to create.

Reference:

Vajda, V., Bercovici, A. 2014. The global vegetation pattern across the Cretaceous-Paleogene mass extinction interval: A template for other extinction events. Global and Planetary Change. doi: 10.1016/j.gloplacha.2014.07.014

Tyrannosaurs hunted in packs?


This video is called Tyrannosaur Rivalry – Planet Dinosaur – Episode 3 – BBC One.

From daily The Guardian in Britain:

Researchers find first sign that tyrannosaurs hunted in packs

Discovery of three sets of dinosaur trackways in Canada reveals that predators were running together

Ian Sample, science editor

Wednesday 23 July 2014 19.36 BST

The collective noun is a terror of tyrannosaurs: a pack of the prehistoric predators, moving and hunting in numbers, for prey that faced the fight of its life.

That tyrannosaurs might have hunted in groups has long been debated by dinosaur experts, but with so little to go on, the prospect has remained firmly in the realm of speculation.

But researchers in Canada now claim to have the strongest evidence yet that the ancient beasts did move around in packs.

At a remote site in the country’s northeast, they uncovered the first known tyrannosaur trackways, apparently left by three animals going the same way at the same time.

Unlike single footprints which have been found before, tyrannosaur trackways are made up of multiple steps, revealing the length of stride and other features of the animal’s movement. What surprised the Canadian researchers was the discovery of multiple tracks running next to each other – with each beast evidently keeping a respectable distance from its neighbour.

Richard McCrea at the Peace Region Palaeontology Research Centre in British Columbia was tipped off about one trackway in October 2011 when a hunting guide working in the area emailed him some pictures. The guide had found one footprint that was already exposed and later uncovered a second heading in the same direction. McCrea made immediate plans to investigate before the winter blanketed the site with snow.

He arrived later the same month and found a third footprint that belonged to the same trackway under volcanic ash. But the real discovery came a year later, when the team returned and uncovered two more sets of tyrannosaur tracks running in the same south-easterly direction.

“We hit the jackpot,” said McCrea. “A single footprint is interesting, but a trackway gives you way more. This is about the strongest evidence you can get that these were gregarious animals. The only stronger evidence I can think of is going back in a time machine to watch them.”

The footprints were so well-preserved that even the contours of the animals’ skin were visible. “You start wondering what it would have been like to have been there when the tracks were made. The word is terror. I wouldn’t want to meet them in a dark alley at night,” McCrea said.

From the size of the footprints, the researchers put the beasts in their late 20s or early 30s – a venerable age for tyrannosaurs. The depth of the prints and other measurements suggest the tracks were left at the same time. They date back to nearly 70m years ago.

Close inspection of the trackways found that the tyrannosaur that left the first set of prints had a missing claw from its left foot, perhaps a battle injury. Details of the study are published in the journal Plos One.

During the expedition, McCrea’s team unearthed more prehistoric footprints from other animals, notably hadrosaurs, or duck-billed dinosaurs. Crucially, these were heading in all sorts of directions, evidence, says McCrea, that the tyrannosaurs chose to move as a pack, and were not simply forced into a group by the terrain.

“When you find three trackways together, going in same direction, it’s not necessarily good evidence for gregarious behaviour. They could be walking along a shore. But if all the other animals are moving in different directions, it means there is no geographical constraint, and it strengthens the case,” said McCrea.

Four-winged Chinese dinosaur discovery


This video says about itself:

Reptiles of the Skies – Walking with Dinosaurs in HQ – BBC

9 November 2012

The Cretaceous period saw the breaking up of the northern and southern landmasses. Flying dinosaurs like Tapejara would master the air and the new coast lines of prehistoric Earth. The largest flying dinosaur Ornithocheirus prepares for a long flight to breeding grounds.

However, this video is about pterosaurs: flying non-dinosaurs, living at the same time as dinosaurs.

From daily The Guardian in Britain:

Four-winged flying dinosaur unearthed in China

Newly discovered Changyuraptor yangi lived 125m years ago and was like ‘a big turkey with a really long tail’

Nishad Karim

Tuesday 15 July 2014 17.18 BST

A new species of prehistoric, four-winged dinosaur discovered in China may be the largest flying reptile of its kind.

The well-preserved, complete skeleton of the dinosaur Changyuraptor yangi features a long tail with feathers 30cm in length – the longest ever seen on a dinosaur fossil. The feathers may have played a major role in flight control, say scientists in the latest issue of Nature Communications, in particular allowing the animal to reduce its speed to land safely.

The 125m-year-old fossil, believed to be an adult, is completely covered in feathers, including long feathers attached to its legs that give the appearance of a second set of wings or “hind wings”. It is the largest four-winged dinosaur ever found, 60% larger than the previous record holder, Microraptor zhaoianus, in the family of dinosaurs known as microraptors.

These beasts were smaller versions of their closely related, larger cousins, the velociraptors made famous in the Jurassic Park movies. They belong to an even wider group including the king of all dinosaurs, Tyrannosaurus rex. At 1.3 metres long and weighing 4kg, the meat-eating C. yangi is one of the largest members of the microraptor family, which tended to weigh 1kg or less.

Microraptors, which are close relatives of modern birds, had many anatomical features that are now only seen in birds, such as hollow bones, nesting behavior, feathers and possibly flight. They were dinosaurs rather than pterosaurs, the more well known flying prehistoric reptiles.

C. yangi was [like] a big turkey with a really long tail,” said Dr Alan Turner from Stony Brook University, one of the authors of the paper. “We don’t know for sure if C. yangi was flying or gliding, but we can sort of piece together this bigger model by looking at what its tail could do. Whether or not this animal could fly is part of a bigger puzzle and we’re adding a piece to that puzzle.”

The fossil was discovered in Liaoning province, northeastern China, an area noted for the large number of feathered dinosaurs found over the past decade, including the first widely acknowledged feathered dinosaur, Sinosauropteryx prima, in 1996.

Before this study, it was thought that the small size of microraptors was a key adaptation needed for flight, but the discovery of C. yangi suggests that aerial ability was not restricted to smaller animals in this group.

See also here.

New horned dinosaur discovery in North America


This video is called Meet Mercuriceratops gemini.

From Tech Times:

Meet Mercuriceratops gemini, a horned-dinosaur with a Roman god’s helmet

By Alexander Saltarin, Tech Times

June 19, 11:13 AM

Scientists have discovered and named a new type of horned dinosaur. Due to the frills on the dinosaur resembling the wings usually found on the helmet of Mercury in depictions of the Roman god, the scientists decided to christen the dinosaur as Mercuriceratops gemini.

The discovery was made after a team of scientists analyzed and studied fossils found in two locations in North America. Some of the fossils were found in Alberta, Canada while the others were found in the state of Montana. Analysis of the fossils showed that the new horned dinosaur would have weighed as much as 2 tons and would have grown to a length of around 20 feet. However, the most distinct feature of the Mercuriceratops is its unique frill. The later part of the scientific name “Gemini” is a reference to the fact that two similar fossils were found in two different locations.

“Mercuriceratops took a unique evolutionary path that shaped the large frill on the back of its skull into protruding wings like the decorative fins on classic 1950s cars,” said Cleveland Museum of Natural History curator of vertebrate paleontology Michael Ryan. “It definitively would have stood out from the herd during the Late Cretaceous.”

Ryan is also the lead author of a paper on the subject published in the online journal Naturwissenschaften.

Scientists believe that the Mercuriceratops thrived during the Late Cretaceous Period approximately 77 million years ago. The name the scientists have chosen literally means “Mercury horned-face,” which aptly described the way the dinosaur’s face would have appeared. The fossil samples found in Canada were discovered in the Dinosaur Provincial Park in Alberta. The park is considered as a UNESCO World Heritage Site and many discoveries have been made in the area. The American fossil on the other hand was found in the north central part of Montana.

The new dinosaur was of particular interest to paleontologists due to the fact that the shape of its skull was unlike any other dinosaur previously known. A dinosaur’s frill, which is often referred to as a neck shield, protects the necks of some dinosaurs like the Triceratops and the newly discovered Mercuriceratops from predators during attacks. The butterfly shaped frill found on the Mercuriceratops shows that evolution had numerous tricks up its sleeves in terms of dinosaur morphology.

Diplodocid dinosaur discovery in Argentina


This video is called Long-Necked Dinosaur Found In Argentina.

From Associated Press:

Dinosaur find tests theories on extinctions

By MICHAEL WARREN

Saturday, June 14, 2014 8:27pm

BUENOS AIRES, Argentina – Dinosaur fossils found in Patagonia provide the first evidence that long-necked, whip-tailed diplodocid sauropods survived well beyond the Jurassic period, when they were thought to have gone extinct, Argentine paleontologists said.

Pablo Gallina, a researcher at Buenos Aires’ Maimonides University, described the find as the first definitive evidence that diplodocids reached South America and the most recent geologic record of this branch of sauropod anywhere.

“It was a surprise, because the first remains we found were very deteriorated, and we didn’t think much of them, but later through careful laboratory work, cleaning rock from the bones, we could see that they were from a diplodocid, something unthinkable for South America.”

Gallina’s team says the fossils show that diplodocids roamed South America during the early Cretaceous era, well after scientists thought these kinds of dinosaurs became extinct. They also suggest that the diplodocid clade, or family group, evolved from other dinosaurs before the Earth’s continents split apart, which is earlier than previously thought.

“Diplodocids were never certainly recognized from the Cretaceous or in any other southern land mass besides Africa,” the authors wrote. “The new discovery represents the first record of a diplodocid for South America and the stratigraphically youngest record of this clade anywhere.”

Explaining the find after the conclusions were published in the PLOS ONE scientific journal, they said the eight vertebrae they recovered belong to a new species they named “Leinkupal laticauda.” That’s a combination of native Mapuche words for “vanishing” and “family,” and Latin words for “wide” and “tail.”

The remains were found in rocky outcrops of the “Bajada Colorada,” a Cretaceous-era formation south of the town of Picun Leufu in Neuquen province.

Paleobiologist Paul Upchurch at University College London, a sauropod expert who was not involved in the study, said it suggests that not all diplodocids succumbed to a mass extinction about 140 million years ago at the end of the Jurassic period.

“Here’s evidence that one or two groups got through. Rather than a total extinction, that it was devastating, but it didn’t completely kill them off,” Upchurch said.

As for the conclusion that the South American find shows diplodocids evolved from a common ancestor earlier than previously thought, Upchurch said “there’s certainly a possibility that this would push the origin back a bit,” given that Africa and South America separated during the Jurassic period. “I’ve been arguing for a long time that these species developed in the middle Jurassic, so for me this isn’t a problem, but others think it happened a bit later,” Upchurch said.

Upchurch also expressed confidence in the claim of a new species, saying “we know enough about sauropods now to get a fairly good idea of what stands out as a diagnosing feature for a new species.”

The research was partly funded by The Jurassic Foundation, formed by producers of the Jurassic Park films.

Sebastian Apesteguia, paleontology director at Maimonides University, noted that the characters in Jurassic Park II ride a motorcycle under a diplodocid’s legs.

“Until now the diplodocids were thought to be North American dinosaurs. They were the classic dinosaurs from all the Hollywood movies,” he said.

Canadian dinosaur age forest fire discovery


This video is called Canadian Amber, A Snapshot of a Late Cretaceous Forest and its Inhabitants.

By Rebekah Marcarelli:

Prehistoric Forest Fire Could Help Researchers Understand Biodiversity Before Dinosaur Extinction

Jun 06, 2014 04:04 PM EDT

Researchers found evidence of a wildfire that occurred 66-million years ago.

The findings were made in Saskatchewan, Canada, which was believed to be much warmer and wetter before the extinction of the dinosaurs, a McGill University news release reported.

“Excavating plant fossils preserved in rocks deposited during the last days of the dinosaurs, we found some preserved with abundant fossilized charcoal and others without it. From this, we were able to reconstruct what the Cretaceous forests looked like with and without fire disturbance,” Hans Larsson, Canada Research Chair in Macroevolution at McGill University, said in the news release.

The plant-life present at the site was similar to those that would pop up in an area that was recovering from a fire. Researchers believe ancient forests recovered from fires similarly than they do today. Plants such as “alder, birch, and sassafras “would have grown in the early stages of recovery and sequoia and ginkgo would have appeared as the recovery progressed.

“We were looking at the direct result of a 66-million-year old forest fire, preserved in stone,” Emily Bamforth, of the Royal Saskatchewan Museum and the study’s first author, said in the news release. “Moreover, we now have evidence that the mean annual temperature in southern Saskatchewan was 10-12 degrees Celsius warmer than today, with almost six times as much precipitation.”

“The abundant plant fossils also allowed us for the first time to estimate climate conditions for the closing period of the dinosaurs in southwestern Canada, and provides one more clue to reveal what the ecology was like just before they went extinct,” Larsson, who is also an Associate Professor at the Redpath Museum said.

Forest fires can have a huge effect on biodiversity in both the plant and animal kingdoms. This type of research could help researchers gain insight into the state of biodiversity directly before the extinction of the dinosaurs. “We won’t be able to fully understand the extinction dynamics until we understand what normal ecological processes were going on in the background.” Larsson said.

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New pterosaur species and their eggs discovered in China


This video is called First 3D Flying Reptile Eggs Discovered in China.

From daily The Guardian in Britain:

Getting ahead: the new crested pterosaur Hamipterus has researchers aflutter

The newly discovered Chinese flying reptile is preserved in huge numbers and with rarely found eggs

The pterosaurs have often been the poor cousins of their relatives when it comes to the public’s understanding of them. Incorrectly called flying dinosaurs, mixed up as bird or even bat ancestors, and considered leathery-winged gliders that could barely fly, let alone walk, they remain a relic of the ‘animals are extinct because they failed’ idea of the 1800s. In fact pterosaurs were remarkably good fliers and many were also superb on the ground, and their real limitation is that their fossil record is generally so poor.

Pterosaurs had incredibly thin bones and while this may have helped make them relatively light, it means they did not fossilise well. As a result, we don’t have many good pterosaur skeletons (and rarely have multiple individuals of one species), and the ones we do have tend to come from a few restricted places where the preservation at that time was exceptional. Pterosaur eggs are even more rare, with all of none turning up between 1784 (when the first pterosaur was described) and 2004, and in the last decade that number has reach a grand total of four.

So the announcement of a discovery of a whole pile of pterosaurs, and with several eggs as well, is clearly a tremendous find. The newly named Hamipterus tianshanensis (its name roughly means ‘the wing of Hami, in the Tianshan mountains’) is from Xinjiang of northwestern China, and dates to around 100-120 million years ago. The fossils uncovered in this arid region include bones of at least 40 different individuals (and estimates of the number of pterosaur bones in the area run into the thousands) and so far five eggs. That is quite a haul and immediately makes this one of the better represented pterosaurs and makes the area a prime spot for pterosaur research. Moreover, all previously described pterosaur eggs had been flattened into two dimensions, but the ones preserved here are the first even that are available in 3D (if a little squished).

Hamipterus was a medium sized pterosaur with a wingspan of up to 3.5 m. It is referred to a group of pterosaurs called the pteranodontoids which include the famous toothless Pteranodon, but also numerous other pterosaurs including many with large teeth. Members of this group are generally considered to be primarily fish eaters and excellent fliers, catching their food on the wing by snatching fish from the surface of the water. The anatomy of the new find matches this interpretation with a series of long teeth in the thin jaws, and the bones were buried around the margin of a large lake. However, it is in the shape of the top of the head that the real interest lies, with specimens bearing a bony crest that runs along the top of the skull and is much larger in some individuals.

Pterosaurs are in part famous for the wild variety of head crests seen on various species. These include those composed of bone, others of soft tissues and some that combined the two. Over the years various hypotheses have been brought forwards for their function, but the main prevailing idea is that in most forms they likely functioned in some forms of sexual display and / or as social dominance signals. In the case of Hamipterus it is suggested that the different sizes may represent males and females (with the males bearing the larger crest) which is very much a reasonable starting hypothesis, but one that requires a degree of further testing. There’s a huge variation in the size and shape of crests in various things that have them (look at the horns in sheep and antlers in deer) and telling male from female, or young male from old male and so on, can be very difficult.

The data is naturally limited at the moment, but the fact that already numerous different individuals and eggs have turned up together is the first on record. There is obviously the potential here for many more animals to be found, and comparable big aggregations of nesting animals are already known for both ancient birds and non-avian dinosaurs. It would not at all be a surprise if pterosaurs did something similar, and indeed this has been suggested in various quarters a number of times, so thepossibility is there, even if it is currently very tentative. Such a haul of specimens though provides an excellent starting point and there is certainly much more to come from this amazing collection.

Wang et al., Sexually Dimorphic Tridimensionally Preserved Pterosaurs and Their Eggs from China, Current Biology (2014), http://dx.doi.org/10.1016/j.cub.2014.04.054 (Current paywall, but open access in 2 weeks).

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