Prehistoric turtles and climate change


This March 2014 video is called Global Warming 56 Million Years Ago: What it Means for Us .

From the University of Florida in the USA:

Tropical turtle discovery in Wyoming provides climate-change clues

Published: February 23 2015

Tropical turtle fossils discovered in Wyoming by University of Florida scientists reveal that when the earth got warmer, prehistoric turtles headed north. But if today’s turtles try the same technique to cope with warming habitats, they might run into trouble.

While the fossil turtle and its kin could move northward with higher temperatures, human pressures and habitat loss could prevent a modern-day migration, leading to the extinction of some modern species.

The newly discovered genus and species, Gomphochelys (pronounced gom-fo-keel-eez) nanus, provides a clue to how animals might respond to future climate change, said Jason Bourque, a paleontologist at the Florida Museum of Natural History at UF and the lead author of the study, which appears online this week in the Journal of Vertebrate Paleontology</em>.

The wayfaring turtle was among the species that researchers believe migrated 500-600 miles north 56 million years ago, during a temperature peak known as the Paleocene-Eocene Thermal Maximum. Lasting about 200,000 years, the temperature peak resulted in significant movement and diversification of plants and animals.

“We knew that some plants and lizards migrated north when the climate warmed, but this is the first evidence that turtles did the same,” Bourque said. “If global warming continues on its current track, some turtles could once again migrate northward, while others would need to adapt to warmer temperatures or go extinct.”

The new turtle is an ancestor of the endangered Central American river turtle and other warm-adapted turtles in Belize, Guatemala and southern Mexico. These modern turtles, however, could face significant roadblocks on a journey north, since much of the natural habitat of these species is in jeopardy, said co-author Jonathan Bloch, a Florida Museum curator of vertebrate paleontology.

“If you look at the waterways that turtles would have to use to get from one place to another, it might not be as easy as it once was,” Bloch said. “Even if the natural response of turtles is to disperse northward, they have fewer places to go and fewer routes available.”

To put the new turtle in evolutionary context, the researchers examined hundreds of specimens from museum collections around the country, including turtles collected during the 1800s housed at the Smithsonian Institution. Co-author Patricia Holroyd, a vertebrate paleontologist at the University of California, Berkeley, said the fossil history of the modern relatives of the new species shows they could be much more wide-ranging, if it were not for their restricted habitats.

The Central American river turtle is one of the most endangered turtles in the world, threatened by habitat loss and its exploitation as a human food source, Holroyd said.

“This is an example of a turtle that could expand its range and probably would with additional warming, but — and that’s a big but — that’s only going to happen if there are still habitats for it,” she said.

Purgatorius, world’s oldest primate?


This video says about itself:

PurgatoriusExtinction of the Dinosaurs

29 November 2014

Purgatorius and the extinction of the dinosaurs.

Scenes from Animal Planet‘s Animal Armageddon.

From Proceedings of the National Academy of Sciences of the United States of America:

Oldest known euarchontan tarsals and affinities of Paleocene Purgatorius to Primates

Significance

Purgatorius has been considered a plausible ancestor for primates since it was discovered, but this fossil mammal has been known only from teeth and jaw fragments. We attribute to Purgatorius the first (to our knowledge) nondental remains (ankle bones) which were discovered in the same ∼65-million-year-old deposits as dentitions of this putative primate. This attribution is based mainly on size and unique anatomical specializations known among living euarchontan mammals (primates, treeshrews, colugos) and fossil plesiadapiforms.

Results of phylogenetic analyses that incorporate new data from these fossils support Purgatorius as the geologically oldest known primate. These recently discovered tarsals have specialized features for mobility and provide the oldest fossil evidence that suggests arboreality played a key role in earliest primate evolution.

Abstract

Earliest Paleocene Purgatorius often is regarded as the geologically oldest primate, but it has been known only from fossilized dentitions since it was first described half a century ago. The dentition of Purgatorius is more primitive than those of all known living and fossil primates, leading some researchers to suggest that it lies near the ancestry of all other primates; however, others have questioned its affinities to primates or even to placental mammals.

Here we report the first (to our knowledge) nondental remains (tarsal bones) attributed to Purgatorius from the same earliest Paleocene deposits that have yielded numerous fossil dentitions of this poorly known mammal. Three independent phylogenetic analyses that incorporate new data from these fossils support primate affinities of Purgatorius among euarchontan mammals (primates, treeshrews, and colugos).

Astragali and calcanei attributed to Purgatorius indicate a mobile ankle typical of arboreal euarchontan mammals generally and of Paleocene and Eocene plesiadapiforms specifically and provide the earliest fossil evidence of arboreality in primates and other euarchontan mammals. Postcranial specializations for arboreality in the earliest primates likely played a key role in the evolutionary success of this mammalian radiation in the Paleocene.

Flowering plants after dinosaur extinction


This video is called Angiosperm (flowering plant) Life Cycle.

From Smithsonian.com in the USA:

Flowering Plants Appeared in Forest Canopies Just a Few Million Years After Dinosaurs Went Extinct

A new study gives scientists some more insight into the weird history of flowering plants

By Mary Beth Griggs

Taking a minute to smell the flowers isn’t that hard nowadays, but angiosperms (a.k.a. flowering plants) weren’t always as ubiquitous as they are now. They appeared rather suddenly in the fossil record, definitively showing up around 132 million years ago. Their sudden appearance has puzzled scientists from Darwin on to the present day, and while today we understand a bit more about how they diversified, scientists are still learning new things about their history.

In a new study published in Geology, scientists think that they’ve figured out another piece of the angiosperm puzzle. Researchers looked at the patterns of leaf veins of flowering plants in tropical forests in Panama and a temperate forest in Maryland. They looked at the leaves of 132 species, reaching the top of the forest canopy with a 131-foot tall crane, and also taking a look at the leaves that had fallen to the forest floor. Leaves that originated at the very top of the trees tended to have a denser collection of veins than the ones further down the tree trunk.

The scientists then compared the patterns found on the leaves in the forests to leaves found in the fossil record, and discovered that flowering plants had reached the heights of the forest canopy around 58 million years ago, during the Paleocene, just a few million years after the dinosaurs went extinct.

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

New prehistoric crocodile discovered, named after Tolkien’s balrog


This video is called Lord of the Rings – Gandalf vs Balrog.

From Sci-News.com:

Anthracosuchus balrogus: Giant Prehistoric Crocodile Discovered

June 4, 2014

Paleontologists have discovered a new species of crocodile-like reptile that swam in the rivers of what is now Colombia during [the] Paleocene, about 60 million years ago.

The newly discovered prehistoric monster has been named Anthracosuchus balrogus.

The specific epithet, balrogus, derives from the Balrog, the name of a ferocious fictional creature that appeared in J.R.R. Tolkien’s novel ‘The Lord of the Rings’ and dwelled deep in the middle-Earth ‘Mines of Moria.’

Anthracosuchus balrogus belongs to Dyrosauridae, a family of now-extinct crocodyliforms that lived from Late Cretaceous to the Eocene.

Originating in Africa, these crocodile-like reptiles swam across the Atlantic Ocean to South America about 75 million year ago. The family somehow survived the extinction event that wiped out the dinosaurs and persisted to become a top predator.

Four specimens of Anthracosuchus balrogus were unearthed in the Cerrejon coal mine, northern Colombia.

“It quickly became clear that the four fossil specimens were unlike any dyrosaur species ever found,” said Dr Alex Hastings from Martin Luther Universität Halle-Wittenberg, who is the lead author of a paper published in the journal Historical Biology.

The crocodyliforms that lived in the Cerrejon ecosystem during the Paleocene, when temperatures were higher than today, thrived and grew to enormous sizes.

“This group offers clues as to how animals survive extinctions and other catastrophes. As we face climates that are warmer today, it is important to understand how animals responded in the past. This family of crocodyliforms in Cerrejon adapted and did very well despite incredible obstacles, which could speak to the ability of living crocodiles to adapt and overcome,” Dr Hastings said.

Anthracosuchus balrogus was about 5 meters long, weighed 410 kg, and had an unusually blunt snout for species in the dyrosaurids family.

“The species’ short snout paired with large jaw muscles typical of dyrosaurids, would give it an incredibly powerful bite,” Dr Hastings said.

It lived in freshwater rivers alongside the famous giant Titanoboa snake (measured up to 18 meters long), ate turtles and fish.

“We couldn’t believe it had such a boxy, short skull and that it was still a dyrosaur. It really busts the mold for these animals. It is such a completely different looking beast than we’ve seen for these crocodile-like animals,” said co-author Dr Jonathan Bloch of Florida Museum.

“The study of dyrosaurids in Cerrejon is providing a better understanding of the early history of crocodiles in the Neotropics,” concluded senior author Dr Carlos Jaramillo of the Smithsonian Tropical Research Institute.

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Paleocene mammal fossil discovery


A modern-day pangolin (Manis pentadactyla) skeleton (top) and the ancient Ernanodon antelios (bottom). CREDIT: © Peter Kondrashov

From Discovery News:

Post-Dinos Mammal Was Fat and Slow

This mammal wasn’t much of a runner. But with the dinosaurs gone, it really didn’t need to be.

By Jennifer Viegas

Tue Sep 11, 2012 06:46 AM ET

Many of the mammals that emerged right after the non-avian dinosaur extinction were hearty creatures, as exemplified by Ernanodon, a beast described in the latest issue of the Journal of Vertebrate Paleontology.

The skeleton that is the focus of the study is nearly complete, revealing how this early mammal looked in the flesh and lived.

“Ernanodon was a badger-sized, rather chunky mammal with a short square skull, extremely reduced dentition and big claws on the forelimbs,” lead author Peter Kondrashov told Discovery News.

The structure of the forelimb indicates that this animal was doing a lot of digging, probably mostly in the search of food,” added Kondrashov, who is an associate professor and chair of the Anatomy Department at the Kirksville College of Osteopathic Medicine.

He and colleague Alexandre Agadjanian analyzed the skeleton, which dates to the Late Paleocene (60 to 55 million years ago). This Ernanodon individual lived in Mongolia. Other, less complete, remains were previously found in China.

“Ernanodon is a unique find and represents one of the most complete skeletons ever collected from the Paleocene of the Naran Bulak locality,” said Agadjanian, who works at the Borissiak Paleontological Institute of the Russian Academy of Sciences.

The animal’s hind limbs were almost flat-footed, so the researchers don’t think Ernanodon was much of a runner. It instead appears to have spent most of its days digging and eating, without much chomping.

“Based on the structure of the teeth — very thin enamel layer, reduced tooth size — it appears that the food was rather soft and did not require a lot of chewing,” Kondrashov explained. “Similar dental structure is observed in mammals that feed on termites, ants and other social insects, so we think that it was specialized in feeding on social insects as well.”

While Ernanodon is long gone and has no direct descendants, the scientists believe this animal was related to a group of extinct mammals known as palaeanodonts. They too had bulky bodies, tiny teeth, and big claws for digging.

These animals are, in turn, related to modern mammals called pangolins, or scaly anteaters, which live in Africa and Asia.

Based on the earlier evidence for Ernanodon, scientists thought the then enigmatic mammal was related to modern armadillos or sloths. While pangolins somewhat resemble these animals in appearance and behavior, they represent a different genus and species.

Ernanodon is just one of many mammals that came to prominence after the great non-avian dinosaur extinction.

“This animal comes from the time period known as the Paleocene, which followed the Cretaceous, so it probably evolved as a result of appearance of numerous new niches after the dinosaurs went extinct,” Kondrashov said.

“We know very little about Paleocene deposits in Asia,” he added, “and this find sheds a lot of light on the early evolution of mammals in Asia.”

See also here.

Dinosaur-age Argentinian mammal discovery


Reconstruction of Cronopio dentiacutus in its native environment during the early Late Cretaceous. Image: Jorge Gonzalez/Guillermo Rougier

From New Scientist:

Sabre-toothed squirrel scurried at dinosaurs’ feet

18:00 02 November 2011 by Colin Barras

Truth is sometimes just as strange as fiction. Palaeontologists have unearthed fossils of a bizarre mammal that lived in the shadow of the dinosaurs and was a dead ringer for the sabre-toothed squirrel star of the computer-animated Ice Age films.

Mammals were a fixture of the dinosaur era, but their remains are rarely preserved. The new fossil, which comes from 95-million-year-old rocks in Argentina, is a tantalising sign of what we are missing. Its 2-centimetre-long skull has large eye sockets, a narrow snout and a formidable pair of long canines unlike anything seen before in Mesozoic mammals.

At the time this creature, dubbed Cronopio, roamed Earth, the marsupial and placental mammals that dominate today had already begun to branch out. But Cronopio was a more primitive beast. Its discovery confirms that early mammals tried out body shapes for which no living parallel exists, says Guillermo Rougier at the University of Louisville in Kentucky, whose team made the find.

Cronopio was dug out of rocks rich in the remains of giant sauropod and theropod dinosaurs. Its large eye sockets indicate it was possibly nocturnal, says Christian de Muizon at the Museum of Natural History in Paris, France, who was not a member of Rougier’s team. “The function of the long canines is difficult to assess,” says Rougier. “There is no real modern model for that.”

The shape of the squirrel’s molars suggests that it may have had a taste for insects, he adds. Rougier named the fossil after fictional characters in the novels of Argentinian writer Julio Cortázar, but he is well aware of its silver screen doppelgänger. “Some ridiculous-looking cartoon characters can sometimes be found later as real fossils,” he says.

Journal reference: Nature, DOI: 10.1038/nature10591.

See also here. And here. And here.

Recently announced findings, published in the journal Science by Maureen O’Leary and colleagues, represent an important step in understanding the early evolution of placental mammals, and sheds light on its relation to the mass extinction of dinosaurs. The scientists report that the majority of living mammals evolved at an explosive rate following the extinction of the dinosaurs some 65 million years ago: here.