paleobiology

Baby Dinosaur Skeleton Unearthed In Canada

The tiny, intact skeleton of a baby rhinoceroslike dinosaur has been unearthed in Canada.

The toddler was just 3 years old and 5 feet (1.5 meters) long when it wandered into a river near Alberta, Canada, and drowned about 70 million years ago. The beast was so well-preserved that some of its skin left impressions in the nearby rock.

The fossil is the smallest intact skeleton ever found from a group of horned, plant-eating dinosaurs known as ceratopsids, a group that includes the iconic Triceratops

Rare find

Finding intact baby dinosaurs is incredibly rare.

“The big ones just preserve better: They don’t get eaten, they don’t get destroyed by animals,” said study co-author Philip Currie, a paleobiologist at the University of Alberta. “You always hope you’re going to find something small and that it will turn out to be a dinosaur.”

Paleontologists had unearthed a few individual bones from smaller ceratopsids in the past. But without intact juvenile skeletons, such bones aren’t very useful, as scientists don’t really know how each bone changes during each stage of the animals’ lives, Currie said.

The team was bone-hunting in Dinosaur Provincial Park in Alberta when Currie came upon what looked like a turtle shell sticking out from a hillside. Upon closer inspection, the fossil turned out to be a frill, the bony decorative headgear that surrounds the back of the head in ceratopsids.

When the team excavated, they found the fossilized skeleton of a tiny dinosaur they identified as a Chasmosaurus belli, a species commonly found in the area.

From the size of the ocular cavities and the proportions of the skull, paleobiologists can say, with a fair degree of confidence, that baby dinosaurs were “really cute”.

Yes, that’s a technical term.

Learned at: Dino 101: Dinosaur Paleobiology (Alberta/Coursera)

Extra credit: http://www.theguardian.com/science/2013/oct/22/beautiful-baby-dinosaur-delights-palaeontologists

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A hypothesized mechanism for the origin of life, an event called abiogenesis.  In this version, called RNA world, small molecules called nucleotides formed in the waters of the early Earth during the Hadean Eon, and polymerized on the surface of clay minerals.  These simple chains of RNA could replicate themselves in solution, but only slowly and inaccurately.  An RNA molecule developed which would fold into a structure that catalyzed RNA polymerization; a ribozyme.  The first ribozymes would replicate their sister strands, and produce copies of themselves and other RNA molecules. 

     In the same environment, long chains of carbon molecules called phospholipids were formed.  These molecules have two parts, the tail, which is hydrophobic, and the head, which is hydrophillic.  Because of these properties phospholipids will stick together and form micelles and vesicles in water.  Vesicles can absorb RNA nucleotides, concentrating them and creating a space where they can replicate, mutate and evolve.  At some point a ribozyme became enclosed within a vesicle, starting a chain reaction that evolved into the multitude of biological forms that we see today.

   Because this event occurred more than 3.8 billion years ago, theories about how and where it happened are highly speculative.  Possible environments for abiogensis include hydrothermal vents on the ocean floor, hyper saline bubbles of water trapped in ice, radioactive lakes or lagoons on earths surface, and even in space or on another planet, brought to earth through a panspermia event.  We have very little molecular evidence of the first cells, but ribozymes and catalytic RNA molecules are embedded in the DNA replication machinery of all life.  Because evidence of this event has almost certainly been lost to time, the true mechanisms of the origin of life may remain a mystery to science.

Take a tour of fossils across geologic time and evolution

A tour of life over geologic time and evolution as evidenced by the fossil record:

Precambrian Fossils I Cambrian Fossils I Ordovician Fossils I Silurian Fossils I Devonian Fossils I Carboniferous Fossils I Permian Fossils I Triassic Fossils I Jurassic Fossils I Cretaceous Fossils I Tertiary Fossils


Also see:

Feathers close up (stock image). The researchers’ hypothesis: The evolution of feathers made dinosaurs more colorful, which in turn had a profoundly positive impact on communication, the selection of mates and on dinosaurs’ procreation. Credit: © thawats / Fotolia [Click to enlarge image]

Why were dinosaurs covered in a cloak of feathers long before the early bird species Archaeopteryx first attempted flight? Researchers from the University of Bonn and the University of Göttingen attempt to answer precisely that question in their article “Beyond the Rainbow” in the latest issue of the journal Science. The research team postulates that these ancient reptiles had a highly developed ability to discern color. Their hypothesis: The evolution of feathers made dinosaurs more colorful, which in turn had a profoundly positive impact on communication, the selection of mates and on dinosaurs’ procreation.

The suggestion that birds and dinosaurs are close relatives dates back to the 19th century, the time when the father of evolutionary theory, Charles Darwin, was hard at work. But it took over 130 years for the first real proof to come to light with numerous discoveries of the remains of feathered dinosaurs, primarily in fossil sites in China. Thanks to these fossil finds, we now know that birds descend from a branch of medium-sized predatory dinosaurs, the so-called theropods. Tyrannosaurus rex and also velociraptors, made famous by the film Jurassic Park, are representative of these two-legged meat eaters. Just like later birds, these predatory dinosaurs had feathers – long before Archaeopteryx lifted itself off the ground. But why was this, particularly when dinosaurs could not fly?

Dinosaurs’ color vision

“Up until now, the evolution of feathers was mainly considered to be an adaptation related to flight or to warm-bloodedness, seasoned with a few speculations about display capabilities” says the article’s first author, Marie-Claire Koschowitz of the Steinmann Institute for Geology, Mineralogy and Paleontology at the University of Bonn. “I was never really convinced by any of these theories. There has to be some particularly important feature attached to feathers that makes them so unique and caused them to spread so rapidly amongst the ancestors of the birds we know today,” explains Koschowitz. She now suggests that this feature is found in dinosaurs’ color vision. After analyzing dinosaurs’ genetic relationships to reptiles and birds, the researcher determined that dinosaurs not only possessed the three color receptors for red, green and blue that the human eye possesses, but that they, like their closest living relatives, crocodiles and birds, were probably also able to see extremely short-wave and ultraviolet light by means of an additional receptor. “Based on the phylogenetic relationships and the presence of tetrachromacy in recent tetrapods it is most likely that the stem species-of all terrestrial vertebrates had photo receptors to detect blue, green, red and uv,” says Dr. Christian Fischer of the University of Göttingen.

This makes the world much more colorful for most animals than it is for human beings and other mammals. Mammals generally have rather poor color vision or even no color vision at all because they tended to be nocturnal during the early stages of their evolution. In contrast, numerous studies on the social behavior and choice of mates among reptiles and birds, which are active during the day, have shown that information transmitted via color exerts an enormous influence on those animals’ ability to communicate and procreate successfully.

Feathers allowed for more visible signals than did fur

We know from dinosaur fossil finds that the precursors to feathers resembled hairs similar to mammals’ fur. They served primarily to protect the smaller predatory dinosaurs – which would eventually give rise to birds – from losing too much body heat. The problem with these hair-like forerunners of feathers and with fur is that neither allow for much color, but tend instead to come in basic patterns of brown and yellow tones as well as in black and white. Large flat feathers solved this shortcoming by providing for the display of color and heat insulation at the same time. Their broad surface area, created by interlocked strands of keratin, allows for the constant refraction of light, which consequently produces what is referred to as structural coloration. This refraction of light is absolutely necessary to produce colors such as blue and green, the effect of metallic-like shimmering or even colors in the UV spectrum. “Feathers enable a much more noticeable optical signaling than fur would allow. Iridescent birds of paradise and hummingbirds are just two among a wealth of examples,” explains Koschowitz.

This work means we must see the evolution of feathers in a whole new light. They provided for a nearly infinite variety of colors and patterns while simultaneously providing heat insulation. Prof. Dr. Martin Sander of the University of Bonn’s Steinmann Institute summarizes the implications of this development: “This allowed dinosaurs to not only show off their colorful feathery attire, but to be warm-blooded animals at the same time – something mammals never managed.”


Story Source:

The above story is based on materials provided by Universität Bonn. Note: Materials may be edited for content and length.


Journal Reference:

  1. M.-C. Koschowitz, C. Fischer, M. Sander. Beyond the rainbow. Science, 2014; 346 (6208): 416 DOI: 10.1126/science.1258957

Fascinating!  Really, this got me thinking big time.

What happened…when the object apparently responsible for the extinction of the dinosaurs hit the Earth 65 million years ago?

“First, there was a gigantic fireball brighter than the Sun as the comet plunged to its death, not with a whimper, but a bang. One casualty was the ozone layer, which temporarily vanished. Seconds after the big comet first encountered Earth’s upper atmosphere, it carved out a crater - now buried - 200 kilometers wide and 25 kilometers deep. All that debris shot up into the sky and came back again, all over the Earth. No place would have been spared a hit of at least a tiny particle.

Reacting to this incredible bombardment, the air temperature rose quickly until, for mor ethan two hours, the worldwide temperature reached that of an oven set to broiling. The sky glowed like an electric heater. Ground fires flared everywhere. Then the temperatures started to drop, and drop, and drop. A thick cloud of dust blackened the world, setting off a several-month period without sunlight. Rains poisoned with sulfuric and nitric acid added to the misery.

With blow after blow to the biosphere…most large land-roving dinosaurs probably died within weeks. Other creatures took longer; those who survived one disaster would perish in the next one. Slowly, the great cloud dissipated, and temperatures began to rise again, this time due to a greenhouse effect that lasted for centuries or millennia. Overall, perhaps 70 percent of all the species of life died during the siege, and in North America at least, about half of the species of flowering plants.

But not everybody. Some of the hardier representatives of many species, including the ones equipped to hibernate, made it through the impact winter. Enough small mammals survived that, when the biosphere finally started to recover, they began to proliferate and flourish.

Impacts clear the decks for new forms of life. The fossil record shows that after major impacts, there is a burst of speciation. New life forms fill the niches that the old ones leave behind. If there were no impacts, the thrust of evolution might have slowed down, and today there would be a different set of species inhabiting the Earth.”

David H. Levy, Gene Shoemaker in an exchange about comets and cosmic collisions| Impact Jupiter: The Crash Of Comet Shoemaker-Levy 9

[image credit]

Latest Paleo illustration from Nobu Tamura:
THE OLDEST NORTH AMERICAN VERTEBRATE
Astraspids: Jawless armored fish from the Ordovician 
455 million years ago

Source: Nobu Tamura / Spinops

Astraspis (‘star shield’) is an extinct genus of primitive jawless fish from the Ordovician of Central North America and Bolivia (Astraspis - Wikipedia)

Astraspis desiderata Walcott, 1892
Chordata → Craniata → Agnatha → †Pteraspidimorpha → †Astraspida

Late Ordovician  //  Harding Fm  //  Colorado, US
Length: 20 cm

The headshield of Astraspis was made of hundreds of small bony plates called tesserae. With Eriptychius, they constitute the earliest known definite vertebrates from North America. 

April 20, 2014 // Copyright © Nobu Tamura under Creative Commons 3.0 Unported 

More information at Tamura's Paleo Exhibit …

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Feathers for Tyrannosaurs

Feathery dinosaurs can be an acquired taste. Not everyone likes seeing animals that have traditionally been wrapped in scales begin to sprout brightly-colored plumage, especially when such changes threaten to dispel the menacing appearance of Hollywood dinosaur villains like Jurassic Park‘sVelociraptor. Of course, alterations to some dinosaurs raise the dander of fossil aficionados more than others. A fluffy Siats will stir debate among experts, but, simply by dint of the dinosaur’s celebrity, the prospect of a fuzzy tyrannosaur is a pop culture flashpoint in the tussle between dinosaurs of our childhood and the animals science is uncovering.

The impending release of Walking With Dinosaurs 3D has put tyrannosaur feathers on my mind again. The Land Before Time it ain’t, but the gorgeously-rendered animated film will undoubtedly excite the latest generation of young dinosaur fans. That’s why many paleontologists and dinosaur fans are disappointed that CGI docudrama’s villains, a gaggle of iridescent Gorgosaurus, are devoid of any fluff or fuzz.

In the grand scheme of the tyrannosaur family tree, Gorgosaurus was a large, sleek, and agile member of a subgroup called tyrannosaurids. This is the category of the most famous tyrant dinosaurs, including Tyrannosaurusitself. Yet we know relatively little about what the outside of these dinosaurs looked like. There are some rumored skin impressions – some lost, others frustratingly unpublished – that show tyrannosaurids had pebbly scales, at the very least. Befitting the traditional view of dinosaurs as scabrous reptiles, the filmmakers decided to go the conservative route and reviveGorgosaurus sans fluff.

Body size has played into the argument for scaly tyrannosaurids, too. If a 30 foot long, two ton plus Gorgosaurus had an active, hot-running metabolism, then wouldn’t an insulating coat of fluff cause the predator to overheat? Scale supporters could concede that small tyrannosaurs, and maybe even tyrannosaurid chicks, had fluff, but the prospect of a heat-addledTyrannosaurus has helped keep large tyrannosaurs scaly.

Enter Yutyrannus. Not long after the Walking With Dinosaurs 3D settled on their scaly Gorgosaurus, paleontologist Xu Xing and colleagues described a roughly 30 foot long, one and a half ton tyrannosauroid that wore an expansive coat of protofeathers. Yutyrannus, along with some experimental work on how large animals shed body heat, suggest that body size was not a barrier to being a fluffy dinosaur.

Yutyrannus was described too late to change the look of Hollywood’s latest take on Gorgosaurus. And fans of the scaly-skinned model are often quick to point out a relational barrier between the two dinosaurs. The 125 million year old Yutyrannus was an archaic from categorized as a tyrannosauroid, while Gorgosaurus was a later and more derived member within the tyrannosaurid subgroup. Since the only tyrannosaurs so far discovered with protofeathers are the tyrannosauroids Yutyrannus and the comparatively tiny Dilong, and tyrannosaurids only left behind scaly skin, then maybe tyrannosaurs shed their simple plumage over evolutionary time.

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The Evolutionary Origins of Eusocial Insects

The extreme altruism exhibited by euso­cial insects was one of the Darwin’s dilemmas when developing his theory of natural selection. In The Origin of Species, Darwin described sterile worker castes in the social insects as “the one special difficulty, which at first appeared to me insuperable and actually fatal to my whole theory”.

The Scientist (January 1, 2015) has an article titled “The Genetics of Society” , summarizing how some researchers aim to unravel the molecular mechanisms by which a single genotype gives rise to diverse castes in eusocial organisms. See the article here: Feature: The Genetics of Society .

The cited research is yet another example of how modern molecular science is unraveling the fine details of the history of life on earth, as Darwin’s Dilemma long ago ceased being a dilemma.

How can nature select for a worker (bee or ant, for example) phenotype that solely exists to help others reproduce, when it does not have any offspring of its own? We now understand that worker behavior can evolve because workers still pass on their genes through the related offspring they help raise.

Above: A GIANT MOTHER: A queen Texas leafcutter ant (Atta texana) is many times larger than her worker daughters — who are, importantly,  all genetic sisters.

Recent research has applied genomics (gene expression transcriptomics), proteomics, phylogenomics and epigenomics, many of the various “omics” technologies that have matured and become inexpensive over the past decade.

Some of the notable findings/hypotheses supported by evidence that has emerged in recent years, as summarized in the article:

1) Each eusocial lineage evolved from a solitary ancestor—a species in which a single genome produced a single adult phenotype, as is the case for the majority of insects alive today. Based on the morphology of both extant and extinct species, it was long believed that bees represented the most ancestral of the hymenopteran lineages. However, recent high-throughput sequencing of transcriptomes indicates that wasps may in fact be the more ancient group, with bees and ants having diverged from the wasp lineage around 145 million years ago, in the lower Cretaceous Period.

2) Moreover, recent investigations of division of labor in eusocial insects with simpler societies have highlighted many of the same toolkit genes associated with castes found in the highly eusocial honeybee.

3) Some “old” genes have adopted new functions in certain species. The ancestral function of juvenile hormone (JH), for example, was to produce yolk for egg development. And in all eusocial insects studied to date, JH is upregulated in queens (i.e., the gene is expressed more), suggesting they retain the gene’s ancestral function. However, JH has also evolved a new function—regulating foraging behavior in workers of several eusocial species.

The first social insects are believed to have evolved in the upper Jurassic, and separately and independently in Insect Order Hymenoptera (bees, ants and wasps) and Infraorder Isoptera (termites). and that, among these, wasps were likely first.

Below is a detailed Cretaceous wasp insect fossil from Brazil, preserved as if in flight:

Class Insecta, Order Hymenoptera indet.
Geological Time: Lower Cretaceous Late Aptian-Cenomanian (108-92 million years ago)
Size: 14 mm long with 20 mm wingspan
Fossil Site: Crato Formation, Nova Olinda Member, Ceara, Brazil

Image credit: Virtual Fossil Museum (CC BY-NC 4.0)

Below is a lower Cretaceous termite from the Crato Formation in Brazil:

Image Credit: Fossil Mall Science (CC BY-NC 4.0)

Below is a winged ant in Miocene Dominican fossil amber:

Image Credit: Fossil Mall Science (CC BY-NC 4.0)

The final image is of an Alate, the sexual form of termites that swarm from the colony in huge numbers to fly weakly to a new site to form another colony, Soon they shed their wings and set up housekeeping. Modern-day termites time the emergence of all colonies in a region to swamp the predators, giving at least a few the opportunity to found new colonies.

Image credit: Virtual Fossil Museum (CC BY-NC 4.0)

Cosmic Explosion Left Imprint in Fossil Record

Ancient iron-loving bacteria may have scooped up evidence of a nearby supernova explosion 2.2 million years ago, leaving an extraterrestrial iron signature in the fossil record, according to German researchers presenting their findings at a recent meeting of the American Physical Society.

In 2004, German scientists reported finding an isotope of iron in a core sample from the Pacific Ocean that does not form on Earth. The scientists calculated the decay rate of the radioactive isotope iron-60 and determined that the source was from a nearby supernova about 2 million years ago. The blast, they say, was close enough to Earth to seriously damage the ozone layer and may have contributed to a marine extinction at the Pliocene-Pleistocene geologic boundary.

Shawn Bishop, a physicist with the Technical University of Munich in Germany and the primary author of the recent study, wondered if traces of the supernova could be found in the fossil record as well. Some deep sea bacteria soak up iron creating tiny magnetic crystals. These 100-nanometer-wide crystals form long chains inside highly-specialized organelles called magnetosomes which help the bacteria orient themselves to Earth’s magnetic field. Using a core sample from the eastern equatorial Pacific Ocean, Bishop and his team sampled strata spaced about 100,000 years apart. By using a chemical treatment that extracts iron-60 while leaving other iron, the scientists then ran the sample through a mass spectrometer to determine whether iron-60 was present.

And in the layers around 2.2 million years ago, tiny traces of iron-60 appeared.

Although the scientists are not sure which star exploded to rain radioactive iron onto Earth, the scientists refer to a paper from 2002 that points to several supernovae generated in the Scorpius-Centaurus star association. The group of young stars, just 130 parsecs (about 424 light-years) from Earth, has produced 20 supernovae within the past 11 million years.

Source: Nature.com and APS.org “Abstract X8.00002: Search for Supernova 60FE in the Earth’s Fossil Record”, Physical Review Letters, “Evidence for Nearby Supernova Explosions” and 60Fe Anomaly in a Deep-Sea Manganese Crust and Implications for a Nearby Supernova Source.

image: Ancient iron-loving bacteria may have collected particles from a supernova that exploded about 2.2 million years ago. The Crab Nebula, shown here in this image from NASA’s Hubble Space Telescope, is much younger having exploded in 1054.
credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)

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EARLIEST KNOWN COMPLETE NERVOUS SYSTEM DISCOVERED
Extinct ‘Mega Claw’ Creature Had Spider-Like Brain  
October 16, 2013 - University of Arizona news release

A team of researchers led by University of Arizona Professor Nick Strausfeld and London Natural History Museum’s Greg Edgecombe have discovered the earliest known complete nervous system, exquisitely preserved in the fossilized remains of a never-before described arthropod that crawled or swam in the ocean 520 million years ago.

The find suggests that the ancestors of chelicerates – spiders, scorpions and their kin – branched off from the family tree of other arthropods – including insects, crustaceans and millipedes – more than half a billion years ago.

Continue reading
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IMAGES
Fossil of the megacheiran Alalcomenaeus, a distant relative of scorpions and spiders. (Photo: N. Strausfeld et al.)

Close-up of the head region of the Alalcomenaeus fossil specimen with superimposed colors, using a microscopy technique revealing the distribution of chemical elements in the fossil.  //  Copper shows up as blue, iron as magenta and the CT scans as green. The coincidence of iron and CT denote nervous system. The creature boasted two pairs of eyes (ball-shaped structures at the top). (Photo: N. Strausfeld/UA) 

Illustration of the nervous systems of the Alalcomenaeus fossil (left), a larval horseshoe crab (middle) and a scorpion (right). Diagnostic features revealing the evolutionary relationships among these animals include the forward position of the gut opening in the brain and the arrangement of optic centers outside and inside the brain supplied by two pairs of eyes. (Illustration: N. Strausfeld/UA) 

(via UANews)

Newfound Giant Dinosaur Ruled Before T.Rex

Tyrannosaurs reign as the most famous of all meat-eating dinosaurs. But they didn’t always dominate, suggests the newly discovered bones of a massive carnivorous dinosaur that lived 98 million years ago.

Named Siats meekerorum (pronounced “See-atch”), the dinosaur discovered in eastern Utah by paleontologists was a previously unknown “apex,” or top, predator that ruled long before North America’s tyrannosaurs came to power.

In the Nature Communications study published today, Lindsay Zanno of North Carolina State University and Peter Makovicky of Chicago’s Field Museum of Natural History add to our knowledge of gigantic dinosaur predators prior to the days of Tyrannosaurus rex, which lived some 67 million years ago.

At full size, the two-legged carnivore may have weighed more than four tons and stretched nearly the length of a school bus.

The discoverers report that the dinosaur’s first (or genus) name is a tribute to its predatory prowess. In the legends of Utah’s native Ute tribe, “Siats” is the name of a voracious monster.

100-Million-Year-Old Spider Attack Preserved in Amber

“Paleontologists have discovered an extraordinarily rare fossil of a spider attacking a wasp caught in its web.

This piece of amber preserved the event in remarkable detail, an action that took place some 100 million years ago in the Hukawng Valley of Myanmar.

The fossil also contains the body of a male spider in the same web. This provides the oldest evidence of social behavior in spiders, which still exists in some species but is fairly rare. Most spiders have solitary, often cannibalistic lives, and males will not hesitate to attack immature species in the same web.

“This juvenile spider was going to make a meal out of a tiny parasitic wasp, but never quite got to it,” said Prof George Poinar Jr. of the Oregon State University and world expert on insects trapped in amber, who co-authored a paper in the Historical Biology: An International Journal of Paleobiology.

“Spiders are ancient invertebrates that researchers believe date back some 200 million years, but the oldest fossil evidence ever found of a spider web is only about 130 million years old. An actual attack such as this between a spider and its prey caught in the web has never before been documented as a fossil,” the researcher said.”

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Life-Producing Phosphorus Was Carried To Earth By Meteorites

Scientists may not know for certain whether life exists in outer space, but new research from a team of scientists led by a University of South Florida astrobiologist now shows that one key element that produced life on Earth was carried here on meteorites.

In an article published in the new edition of the Proceedings of the National Academies of Sciences, USF Assistant Professor of Geology Matthew Pasek and researchers from the University of Washington and the Edinburg Centre for Carbon Innovation, revealed new findings that explain how the reactive phosphorus that was an essential component for creating the earliest life forms came to Earth.

The scientists found that during the Hadean and Archean eons – the first of the four principal eons of the Earth’s earliest history – the heavy bombardment of meteorites provided reactive phosphorus that when released in water could be incorporated into prebiotic molecules. The scientists documented the phosphorus in early Archean limestone, showing it was abundant some 3.5 billion years ago.

The scientists concluded that the meteorites delivered phosphorus in minerals that are not seen on the surface of the Earth, and these minerals corroded in water to release phosphorus in a form seen only on the early Earth.

The discovery answers one of the key questions for scientist trying to unlock the processes that gave rise to early life forms: Why don’t we see new life forms today?

“Meteorite phosphorus may have been a fuel that provided the energy and phosphorus necessary for the onset of life,” said Pasek, who studies the chemical composition of space and how it might have contributed to the origins of life. “If this meteoritic phosphorus is added to simple organic compounds, it can generate phosphorus biomolecules identical to those seen in life today.”

Pasek said the research provides a plausible answer: The conditions under which life arose on the Earth billions of years ago are no longer present today.

“The present research shows that this is indeed the case: Phosphorus chemistry on the early Earth was substantially different billions of years ago than it is today,” he added.

The research team reached their conclusion after examining Earth core samples from Australia, Zimbabwe, West Virginia, Wyoming and in Avon Park, Florida

Previous research had showed that before the emergence of modern DNA-RNA-protein life that is known today, the earliest biological forms evolved from RNA alone. What has stumped scientists, however, was understanding how those early RNA–based life forms synthesized environmental phosphorus, which in its current form is relatively insoluble and unreactive.

Meteorites would have provided reactive phosphorus in the form of the iron–nickel phosphide mineral schreibersite, which in water released soluble and reactive phosphite. Phosphite is the salt scientists believe could have been incorporated into prebiotic molecules.

Of all of the samples analyzed, only the oldest, the Coonterunah carbonate samples from the early Archean of Australia, showed the presence of phosphite, Other natural sources of phosphite include lightning strikes, geothermal fluids and possibly microbial activity under extremely anaerobic condition, but no other terrestrial sources of phosphite have been identified and none could have produced the quantities of phosphite needed to be dissolved in early Earth oceans that gave rise to life, the researchers concluded.

The scientists said meteorite phosphite would have been abundant enough to adjust the chemistry of the oceans, with its chemical signature later becoming trapped in marine carbonate where it was preserved.

It is still possible, the researchers noted, that other natural sources of phosphite could be identified, such as in hydrothermal systems. While that might lead to reducing the total meteoric mass necessary to provide enough phosphite, the researchers said more work would need to be done to determine the exact contribution of separate sources to what they are certain was an essential ingredient to early life.

via University of South Florida

Mesozoic moose by Hyrotrioskjan
I
’ve taken the liberty of editing this description by the artist (who is not a native speaker of English):

Therizinosaurs are said to be found in non-arid strata. They have huge feet which are perfect to cross swamps. The long neck could be used to grab water plants. Some modern birds have closable nostrils… maybe a feature which is older than we think.

I don’t mean to say Therizinosaurs were semiaquatic; I suggest instead a lifestyle  similar to the modern moose, often seen grazing in the water.

Therizinosaurs may have carried their young on their backs. The thorax was very wide, as far as know, and together with muscles, skin and feathers it was maybe a nice place to rest when Mum was searching for food.

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The booth at Fantasy Con that Robert Bakker was at, the Morrison Natural History Museum’s booth.  Look at all the beautiful skull casts!  Wished I’d had the dough to take some home with me!

See details here.