300-million-year-old platypus-like mammal ancestor’s blood, new research


This April 2017 video says about itself:

The three different ways mammals give birth – Kate Slabosky

All mammals share certain characteristics, like warm blood and backbones. But despite their similarities, these creatures also have many biological differences — and one of the most remarkable differences is how they give birth. Kate Slabosky details the placental, marsupial, and monotreme methods of giving birth.

View full lesson here.

From University College London in England:

Human pregnancy dependent on cells evolved in platypus-like animal 300 million years ago

July 10, 2019

Platelet cells, which prevent mammals from bleeding non-stop, first evolved around 300 million years ago in an egg-laying animal similar to the modern duck-billed platypus, finds joint research by UCL and Yale University.

This event was a prerequisite for the origin of placental development in mammals, including human beings.

The paper, published as a peer-reviewed opinion piece in Biology Letters, suggests that platelet cells were critical in the evolution of eutherian mammals, to which humans belong, and which are distinguished by a deep invasive placenta (haemochorial placentation), by where maternal blood comes in direct contact with the fetus.

Co-led by Professors John Martin (UCL Division of Medicine) and Günter Wagner (Yale University), the research finds that platelet cells, which clot blood caused by cuts or lesions, enabled haemochorial placentation, helping the mother prevent haemorrhaging at birth.

In the paper researchers show that an egg-laying animal similar to a modern duck-billed platypus started creating platelets — possibly by chance — and these were passed on when this animal group diverged around [later than] 300 million years ago into monotremes (the first mammal group), of which the existing duck-billed platypus and echidna are living descendants, marsupials (also mammals) and eutherian mammals, which include modern humans.

UCL Professor of Cardiovascular Medicine, John Martin, said: “We have shown with convincing evidence that platelets occurred 300 million years ago even before monotremes arose.

“This unique feature subsequently allowed the placenta to develop, which led to the eutherian mammals and therefore human beings.

“During birth, safe disconnection of the placenta from the uterus is essential for the survival of the mother and child, so without platelets, neither would have survived and the evolutionary step to eutherian mammals, including human beings, would never have happened.”

This research was undertaken as part of the ‘Yale UCL Collaborative’: a strong relationship between the two universities designed to increase creativity.

Yale Professor of Ecology and Evolutionary Biology, Günter Wagner, said: “The unique presence of platelets in mammals explains why deeply invasive placentation is limited to mammals, even though live birth is found in many other animal lineages, but not invasive placentation.”

The authors met through the ‘Yale UCL Collaborative’, which promotes joint research and student exchange, and this year is celebrating 10 years, since its inception.

Professor Martin said: “The primary goal of the Yale UCL Collaborative is to reach higher levels of creativity and quality of idea than we would have achieved alone.

“Through this partnership, I have been able to work with Professor Wagner, a world-leading expert in evolutionary biology, and test and challenge my theory of the evolution of eutherian placentation.

“Through this joint research we have concluded the origins of platelets ultimately led to human evolution.”

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Great white sharks’ small Jurassic ancestor


This 23 July 2018 video says about itself:

In the first video of this year’s Shark Week we investigate the earliest evolution of the sharks, and look at just where and when these incredibly remarkable animals came from.

From the University of Vienna in Austria:

The ancestor of the great white shark

The unique tooth structure of the great white shark gives new insights into its origin

July 8, 2019

Mackerel sharks (Lamniformes) are a group consisting of some of the most iconic sharks we know, including the mako shark (the fastest shark in the world), the infamous great white shark and Megalodon, the biggest predatory shark that has ever roamed the world’s oceans. An international team of researchers around Patrick L. Jambura from the University of Vienna found a unique feature in the teeth of these apex predators, which allowed them to trace back the origin of this group to a small benthic shark from the Middle Jurassic (165 mya). Their study was recently published in the journal Scientific Reports.

Similar to humans, shark teeth are composed of two mineralized structures: a hard shell of hypermineralized tissue (in humans enamel, in sharks enameloid) and a dentine core. Depending on the structure of the dentine we distinguish between two different types: orthodentine and osteodentine.

Orthodentine has a very compact appearance and is similar to the dentine we can find in human teeth. In shark teeth, orthodentine is confined to the tooth crown. In contrast, the other dentine type is spongious in appearance and resembles real bone and therefore is called osteodentine. It can be found in the root, anchoring the tooth to the jaw and in some species also in the tooth crown where it supports the orthodentine.

Using high resolution CT scans, Patrick L. Jambura and his colleagues examined the tooth composition of the great white shark and its relatives and found a peculiar condition of the teeth of members of this group: the osteodentine of the roots intrudes into the crown and replaces the orthodentine there completely, making it the only type of dentine being present. This condition is not known from any other shark, which all possess orthodentine to some degree and thus it is confined to members of this group.

Another species that was examined was the fossil shark Palaeocarcharias stromeri, which is well-represented by complete skeletons from the famous 150 million-year-old Solnhofen Plattenkalks of South Germany. The oldest find of this species is from the Middle Jurassic (165 million years ago) and it didn’t have much in common with today’s mackerel sharks. Palaeocarcharias was a small sluggish benthic shark, not exceeding lengths of more than a metre and seemingly hunted small fish in shallow waters. To this day, its affiliation has been a riddle to scientists, since its body shape resembles a carpet shark, while its fang like teeth are similar to mackerel sharks. The examination of the tooth microstructure yielded the presence of the same unique tooth composition that is found only in great white sharks and their relatives. The shared tooth histology is a strong indicator that this small inconspicuous shark gave rise to one of the most iconic shark lineages that includes giants like the extinct Megalodon or the living great white shark.

“Orthodentine is known for almost all vertebrates — from fish to mammals, including all modern sharks, except for the mackerel sharks. The discovery of this unique tooth structure in the fossil shark Palaeocarcharias strongly indicates that we found the oldest known ancestor of the great white shark and shows that even this charismatic giant shark started on a shoestring” states Patrick L. Jambura.

How to draw a Tyrannosaurus rex


This 30 May 2019 video from London, England says about itself:

How to draw a T. rex | Natural History Museum

Learn to draw a cartoon T. rex by following our simple instructions.

Get more dinosaur drawing tips here.

Enjoy dinosaur facts, quizzes and crafts here.

Dinosaurs extinct, lichens survived


This 25 January 2018 video says about itself:

What’s in a Lichen? How Scientists Got It Wrong for 150 Years | Short Film Showcase

For 150 years, scientists believed lichen were defined by a symbiotic relationship between a fungus and algae. Meet the team of researchers who upended this belief in this short film by Andy Johnson, Talia Yuki Moore, Chris A. Johns, and Kate Furby.

From the Field Museum in the USA:

When the dinosaurs died, lichens thrived

Mass extinction hurt land plants, but DNA shows that some fungus/plant combo organisms rose up

June 28, 2019

Summary: When the asteroid hit, dinosaurs weren’t the only ones that suffered. Clouds of ash blocked the sun and cooled the planet’s temperature, devastating plant life. But fungi, which decompose dead stuff, did well. So what happened to the lichens, which are made of a plant and fungus living together as one organism?

When an asteroid smacked into the Earth 66 million years ago, it triggered mass extinctions all over the planet. The most famous victims were the dinosaurs, but early birds, insects, and other life forms took a hit too. The collision caused clouds of ash to block the sun and cool the planet’s temperature, devastating plant life. But a new study in Scientific Reports shows that while land plants struggled, some kinds of lichens — organisms made of fungi and algae living together — seized the moment and evolved into new forms to take up plants’ role in the ecosystem.

“We thought that lichens would be affected negatively, but in the three groups we looked at, they seized the chance and diversified rapidly,” says Jen-Pang Huang, the paper’s first author, a former postdoctoral researcher at the Field Museum now at Academia Sinica in Taipei. “Some lichens grow sophisticated 3D structures like plant leaves, and these ones filled the niches of plants that died out.”

The researchers got interested in studying the effects of the mass extinction on lichens after reading a paper about how the asteroid strike also caused many species of early birds to go extinct. “I read it on the train, and I thought, ‘My god, the poor lichens, they must have suffered too, how can we trace what happened to them?'” says Thorsten Lumbsch, senior author on the study and the Field Museum’s curator of lichenized fungi.

You’ve seen lichens a million times, even if you didn’t realize it. “Lichens are everywhere,” says Huang. “If you go on a walk in the city, the rough spots or gray spots you see on rocks or walls or trees, those are common crust lichens. On the ground, they sometimes look like chewing gum. And if you go into a more pristine forest, you can find orange, yellow, and vivid violet colors — lichens are really pretty.” They’re what scientists call “symbiotic organisms” — they’re made up of two different life forms sharing one body and working together. They’re a partnership between a fungus and an organism that can perform photosynthesis, making energy from sunlight — either a tiny algae plant, or a special kind of blue-green bacterium. Fungi, which include mushrooms and molds, are on their own branch on the tree of life, separate from plants and animals (and actually more closely related to us than to plants). The main role of fungi is to break down decomposing material.

During the mass extinction 66 million years ago, plants suffered since ash from the asteroid blocked out sunlight and lowered temperatures. But the mass extinction seemed to be a good thing for fungi — they don’t rely on sunlight for food and just need lots of dead stuff, and the fossil record shows an increase in fungal spores at this time. Since lichens contain a plant and a fungus, scientists wondered whether they were affected negatively like a plant or positively like a fungus.

“We originally expected lichens to be affected in a negative way, since they contain green things that need light,” says Huang.

To see how lichens were affected by the mass extinction, the scientists had to get creative — there aren’t many fossil lichens from that time frame. But while the researchers didn’t have lichen fossils, they did have lots of modern lichen DNA.

From observing fungi growing in lab settings, scientists know generally how often genetic mutations show up in fungal DNA — how frequently a letter in the DNA sequence accidentally gets switched during the DNA copying process. That’s called the mutation rate. And if you know the mutation rate, if you compare the DNA sequences of two different species, you can generally extrapolate how long ago they must have had a common ancestor with the same DNA.

The researchers fed DNA sequences of three families of lichens into a software program that compared their DNA and figured out what their family tree must look like, including estimates of how long ago it branched into the groups we see today. They bolstered this information with the few lichen fossils they did have, from 100 and 400 million years ago. And the results pointed to a lichen boom after 66 million years ago, at least for some of the leafier lichen families.

“Some groups don’t show a change, so they didn’t suffer or benefit from the changes to the environment,” says Lumbsch, who in addition to his work on lichens is the Vice President of Science and Education at the Field. “Some lichens went extinct, and the leafy macrolichens filled those niches. I was really happy when I saw that not all the lichens suffered.”

The results underline how profoundly the natural world we know today was shaped by this mass extinction. “If you could go back 40 million years, the most prominent groups in vegetation, birds, fungi — they’d be more similar to what you see now than what you’d see 70 million years ago,” says Lumbsch. “Most of what we see around us nowadays in nature originated after the dinosaurs.”

And since this study shows how lichens responded to mass extinction 66 million years ago, it could shed light on how species will respond to the mass extinction the planet is currently undergoing. “Before we lose the world’s biodiversity, we should document it, because we don’t know when we’ll need it,” says Huang. “Lichens are environmental indicators — by simply doing a biodiversity study, we can infer air quality and pollution levels.”

Beyond the potential implications in understanding environmental impacts and mass extinctions, the researchers point to the ways the study deepens our understanding of the world around us.

“For me, it’s fascinating because you would not be able to do this without large molecular datasets. This would have been impossible ten years ago,” says Lumbsch. “It’s another piece to the puzzle to understanding what’s around us in nature.”

“We expect a lot of patterns from studying other organisms, but fungi don’t follow the pattern. Fungi are weird,” says Huang. “They’re really unpredictable, really diverse, really fun.”

This study was contributed to by researchers from the Field Museum, Kasetsart University, Brigham Young University, and Academia Sinica.

Prehistoric birds’ blue feathers, new research


This 26 June 2019 video says about itself:

An ancient relative of today’s rollers with a deep blue hue adds to our understanding of nature’s prehistoric palette.

SOMEWHERE OVER THE rainbow 48 million years ago, a happy little blue bird flew—until it soared over a lake belching toxic gases and died. The lake’s sediments then entombed the bird’s body, exquisitely preserving the oldest fossil evidence of blue feathers ever found.

Described in a study published today in Journal of the Royal Society Interface, the feathers belong to an extinct bird, Eocoracias brachyptera, that was recovered from Germany’s Messel Pit. This wonderland of well-preserved fossils dates back to the Eocene period, which lasted from 56 to 33.9 million years ago.

Researchers could infer E. brachyptera’s blue color only because they could compare it with its modern relatives, the rollers. Tiny structures preserved in the fossilized feathers resemble those that give modern birds either blue or gray hues, depending on their arrangement.

And as far as we know, blue feathers have been fairly uncommon through time: Of the 61 lineages of living birds, only 10 have species with E. brachyptera’s most probable coloration. But since modern rollers are far likelier to have blue than gray feathers, the researchers conclude that the ancient bird was a deep blue. It’s the first time that such a feather color has been reconstructed from the fossil record. “I would say that, for me, that was the most exciting and important part of this research,” says lead study author Frane Babarović, a Ph.D. student at the University of Sheffield.

From the University of Bristol in England:

Blue color tones in fossilized prehistoric feathers

June 25, 2019

Examining fossilised pigments, scientists from the University of Bristol have uncovered new insights into blue colour tones in prehistoric birds.

For some time, paleontologists have known that melanin pigment can preserve in fossils and have been able to reconstruct fossil colour patterns.

Melanin pigment gives black, reddish brown and grey colours to birds and is involved in creating bright iridescent sheens in bird feathers.

This can be observed by studying the melanin packages called melanosomes, which are shaped like little cylindrical objects less than one-thousandth of a millimetre and vary in shape from sausage shapes to little meatballs.

However, besides iridescent colours, which is structural, birds also make non-iridescent structural colours.

Those are, for example, blue colour tones in parrots and kingfishers. Until now, it was not known if such colours could be discovered in fossils.

This blue structural colour is created by the dense arrangement of cavities inside feathers, which scatters the blue light. Underneath is a layer of melanin that absorbs unscattered light.

Paleontologists have shown that the feather itself, which is made of keratin, does not fossilise while the melanin does. Therefore, if a blue feather fossilised, the dark pigment may be the only surviving feature and the feather may be interpreted as black or brown.

Now researchers from the University of Bristol, led by Frane Barbarovic who is currently at the University of Sheffield, have shown that blue feather melanosomes are highly distinct from melanosomes that are from feathers expressing black, reddish-brown, brown and iridescent, but overlap significantly with some grey feather melanosomes.

By looking at plumage colourations of modern representatives of fossil specimen and reconstructing which colour was the most likely present in the fossil specimen, they were able to discriminate between melanosomes significant for grey and blue colour, leading to the reconstruction of prehistoric Eocoracias brachyptera as a predominantly blue bird.

Frane Barbarovic said: “We have discovered that melanosomes in blue feathers have a distinct range in size from most of colour categories and we can, therefore, constrain which fossils may have been blue originally.

“The overlap with grey colour may suggest some common mechanism in how melanosomes are involved in making grey colouration and how these structural blue colours are formed.

“Based on these results in our publication we have also hypothesized potential evolutionary transition between blue and grey colour.”

The research team now need to understand which birds are more likely to be blue based on their ecologies and modes of life. The blue colour is common in nature, but the ecology of this colour and its function in the life of birds is still elusive.

Frane Barbarovic added: “We also need to understand how grey colour is made. This is made in a very different way in birds than it is in mammals. We believe it is related to how the melanosome shape can result in a kind of self-assembling process in the feather and the surface tension of the melanosomes pull them into certain configurations inside a feather as it forms.”

Big flightless Pleistocene bird discovery in Crimea


This 27 June 2019 video says about itself:

CNN: Inside a Crimean cave was a gigantic ancient mystery just waiting to be uncovered: a bird so large that it weighed nearly as much as an adult polar bear.

Giant birds once roamed Madagascar, New Zealand and Australia. The latest fossil find, an intriguing fossilized femur, was recently found in Taurida Cave on the northern coast of the Black Sea. It was discovered along with other fossils, including bison bones, that helped researchers date the now-extinct giant bird to between 1.5 million and 2 million years ago.

When the first early human ancestors arrived in Europe, they might have encountered these birds. The researchers think the bird probably reached the Black Sea region by crossing Turkey and the Southern Caucasus.

From Gizmodo.com, 26 June 2019, by George Dvorsky:

Ancient Bird Weighed Nearly 1,000 Pounds but Could Still Haul Ass Like an Ostrich

Paleontologists working in Crimea have uncovered evidence of the largest bird ever found in Europe. Standing taller than an elephant and weighing nearly 1,000 pounds, this enormous bird could still run at a fast pace when threatened.

Big birds have been discovered in Eurasia before, but nothing quite on this scale. In fact, the only birds that really compare are the extinct elephant birds of Madagascar and the extinct moas of New Zealand. The research paper associated with the discovery—published today in the Journal of Vertebrate Paleontology—claims it’s the biggest bird ever found in the northern hemisphere.

Assigned the name Pachystruthio dmanisensis, this animal’s nearly complete femur was found within the Taurida cave network of Crimea. This lone bone, dated to around 1.8 million years ago, was found alongside other animal remains, including a mammoth, bison, and some large carnivores.

Intriguingly, this time period coincided with the introduction of early humans to the region. A similar collection of fossils was previously uncovered at a nearby site in Dmanisi, Georgia, which happens to be the oldest hominin site outside of Africa. Consequently, these large birds “might have been a source of meat, bones, feathers, and eggshell for early hominin populations,” wrote the authors in the new study, which was led by Nikita Zelenkov from the Russian Academy of Sciences.

That early humans may have hunted these birds is a distinct possibility. Recent evidence suggests humans hunted elephant birds in Madagascar around 6,000 years ago.

“When I first felt the weight of the bird whose thigh bone I was holding in my hand, I thought it must be a Malagasy elephant bird fossil because no birds of this size have ever been reported from Europe. However, the structure of the bone unexpectedly told a different story,” said Zelenkov in a press release. “We don’t have enough data yet to say whether it was most closely related to ostriches or to other birds, but we estimate it weighed about 450 kg (992 pounds). This formidable weight is nearly double the largest moa, three times the largest living bird, the common ostrich, and nearly as much as an adult polar bear.”

Zelenkov’s team used a well-established formula, which took various measurements of P. dmanisensis’s femur, to estimate body mass. Further analysis pointed to a flightless bird that stood 11.5 feet (3.5 meters) tall.

Due to the femur’s long and slim shape—which bore a striking resemblance to the modern ostrich—it’s likely this creature was able to move fast. “Pachystruthio dmanisensis was a good runner, which may be explained by its coexistence with large carnivoran mammals,” the authors wrote in the study. And by large carnivores, the researchers weren’t kidding; the femur was found alongside the remains of giant cheetahs, giant hyenas, and saber-tooth cats.

As to why this creature evolved such a big size, the researchers said it likely had something to do with the arid environment in which it lived. Its large mass and efficient metabolism meant it could make better use of the low-nutrition foods found in the open steppes.

Christopher Torres, a graduate student of integrative biology at the University of Texas at Austin, said this report is “super exciting” for a lot of reasons.

“It expands known occurrences of gigantic birds into a new hemisphere,” he told Gizmodo. “It highlights a third case of gigantism among a rather closely related group of birds that also includes elephant birds and moa. Conventional thought was that birds could afford to lose flight and get really large only if there were no terrestrial mammals to compete with or hide from. This new report of giant birds coexisting with large mammals is forcing us to rethink those assumptions,” said Torres, who wasn’t affiliated with the new research.

To which he added: “This report raises some fascinating evolutionary and ecological questions that I cannot wait to see answered.”