Human Beings? We’re the newest kids on the block!


Click to enlargeTimescale for the evolution of life on Earth

❝ A new study led by scientists from the University of Bristol has used a combination of genomic and fossil data to explain the history of life on Earth, from its origin to the present day.

❝ Palaeontologists have long sought to understand ancient life and the shared evolutionary history of life as a whole.

However, the fossil record of early life is extremely fragmented, and its quality significantly deteriorates further back in time towards the Archaean period, more than 2.5 billion years ago, when the Earth’s crust had cooled enough to allow the formation of continents and the only life forms were microbes.

❝ Dr. Tom Williams, from Bristol’s School of Biological Sciences, said: “Combining fossil and genomic information, we can use an approach called the ‘molecular clock’ which is loosely based on the idea that the number of differences in the genomes of two living species (say a human and a bacterium) are proportional to the time since they shared a common ancestor.”

By making use of this method the team at Bristol and Mark Puttick from the University of Bath were able to derive a timescale for the history of life on Earth that did not rely on the ever-changing age of the oldest accepted fossil evidence of life.

Bravo! I note the frequency of solid science making it into the Web’s version of the popular press from the University of Bristol. Advances, research, divining both the past and future of life and its context regularly appear.

4-foot-long Titanosaur footprints found in the Gobi desert


Professor Shinobu Ishigaki lies next to the footprintAFP/Getty Images

One of the largest ever dinosaur footprints has been found by a joint expedition of Japanese and Mongolian researchers in the Gobi desert.

The giant print measures 106cm (42in) long and 77cm (30in) wide, according to AFP. It is thought to have belonged to a titanosaur, a group of giant, long-necked herbivores. Researchers said the creature may have been more than 30 meters (98ft) long and 20 meters (66ft) tall.

The print was discovered in August in a geologic layer formed between 70 million and 90 million years ago by researchers from Okayama University of Science and the Mongolian Academy of Science…

The print is a cast from sand that flowed into dents left by the creature’s enormous footprint. Its discovery could help scientists understand how titanosaurs walked.

In 2014, a titanosaur skeleton was discovered in Argentina and was dubbed the largest dinosaur ever discovered. A replica of the dinosaur, which has yet to be named, is currently on display at the American Museum of Natural History in New York. It weighed about 70 tons and its skeleton is 37 meters (122ft) long.

I would love to be convinced of the possibility of viewing prehistoric times via some sort of time warp. Scientists would line up for primary source accuracy.

Geologists reach rock layer in crater of dinosaur-killing asteroid


Click to enlargeBBCMundo.com

Geophysicists announced this week that they have successfully collected key samples from the site of the asteroid strike that likely wiped out the dinosaurs.

Scientists have had a literal breakthrough off the coast of Mexico…After weeks of drilling from an offshore platform in the Gulf of Mexico, they have reached rocks left over from the day the Earth was hit by a killer asteroid.

The cataclysm is believed to have wiped out the dinosaurs. “This was probably the most important event in the last 100 million years,” says Joanna Morgan, a geophysicist at Imperial College in London and a leader of the expedition.

Since the 1980s, researchers have known about the impact site, located near the present-day Yucatan Peninsula. Known as Chicxulub, the crater is approximately 125 miles across. It was created when an asteroid the size of Staten Island, N.Y., struck Earth around 66 million years ago. The initial explosion from the impact would have made a nuclear bomb look like a firecracker. The searing heat started wildfires many hundreds of miles away.

After that, came an unscheduled winter. Sulfur, ash and debris clouded the sky. Darkness fell and, for a while, Earth was not itself…

Scientists believe 75 percent of life went extinct during this dark chapter in Earth’s history, including the dinosaurs.

Researchers have sampled Chicxulub before, but this expedition…targets a key part of the crater yet to be studied: a ring of mountains left by the asteroid. This “peak ring” is a fundamental feature of the strike and should tell researchers much more about it, says Sean Gulick, a geophysicist at the University of Texas at Austin, who co-leads the team with Morgan.

For weeks, they’ve been drilling — and going back in time. Each layer of rock they pass through is connected to a part of Earth’s history…

The rocks they’ve pulled out show how life began to recover after the cataclysm, Gulick says. “We’ve got all these limestones and rocks that contain the fossils from the world after the impact, all the things that evolved from the few organisms that survived.”

The research team finally reached the top of the peak ring this week. It appears to be a thick layer of broken, melted rock just beneath a layer of sandstone that may be the leavings of a huge tsunami that was triggered when the asteroid struck.

Gulick thinks the rocks hold clues. For example, if any microscopic organisms survived near the site of the strike, their fossils might be in these samples. In June, the rock cores will be sent back to a lab in Germany for further study.

The asteroid strike marked the end of an era. But the creatures that made it through that catastrophe went on to shape the world again, says Morgan.

“The mammals survived,” she says. “And that led on to our own evolution.”

Some folks might feel what came after the disaster was at least as important as the impact event itself. I’m not so confident. After all, the predominant species may yet complete the destruction of the whole planet.

Neanderthal clue to cancer origins


Abnormal Neanderthal bone (above) compared with normal Neanderthal specimen (below)

A Neanderthal living 120,000 years ago had a cancer that is common today, according to a fossil study.

A fossilised Neanderthal rib found in a shallow cave at Krapina, Croatia, shows signs of a bone tumour…The discovery is the oldest evidence yet of a tumour in the human fossil record, say US scientists.

The research, published in the journal PLOS One, gives clues to the complex history of cancer in humans.

Until now, the earliest known bone cancers have been identified in ancient Egyptian remains from about 1,000-4,000 years ago.

It’s the oldest tumour found in the human fossil record,” Dr David Frayer, the University of Kansas anthropologist who led the US team, told BBC News.

“It shows that living in a relatively unpolluted environment doesn’t necessarily protect you against cancer, even if you were a Neanderthal living 120,000 years ago.”

The fossil was uncovered from an important archaeological site that has yielded almost 900 ancient human bones, along with stone tools…The tumour was diagnosed by a medical radiologist from X-rays and CT scans.

Although efforts to extract ancient DNA from the Neanderthal fossil have proved unsuccessful, the researchers hope other fossils may shed light on cancer in prehistoric humans.

Commenting on the study, Kat Arney, science information manager at Cancer Research UK, said: “Some people think that cancer is only a modern disease, but there’s evidence from fossils, bones and mummies that it’s actually many thousands of years old.

Opens up a whole new range of scary possibilities – but, I’m not even up to an educated guess on this narrow topic. So, I’ll shut up.

Paleontologists find 1st feathered dinosaur fossils in Americas

In 2008, a fossil hunter named Frank Hadfield went for a walk among the hoodoos of Drumheller, Alberta. Up on one of these chunky sandstone minarets studding the southern Albertan badlands, Hadfield spied what appeared to be the remains of a small carnivorous dinosaur. He made a few calls and soon his colleague Francois Therrien, a paleontologist at the nearby Royal Tyrrell Museum of Paleontology, to come have a look…

While they were working on the outcropping, a chunk of it split off the main block. Examining it, Therrien saw it was laced with black streaks. The streaks looked familiar. Like all modern paleontologists, Therrien was acquainted with the spectacular feathered-dinosaur fossils of the Liaoning beds in China, where the idea that dinosaurs are the ancestors of birds got its biggest boost, thanks to the preservation of feathers–both the thread-like ones known as “dinofuzz” and the more familiar shafted kind–in the silky mud of an ancient lake bottom. “If we were in China,” he cracked, “we’d call those feathers.”

Interest piqued, the scientists changed the way they’d usually prepare the fossil, cleaning it to the level of its skin, rather than down to the bone, to see whether more of the curious features could be found. The work was not in vain. The 2008 specimen, along with another found in 2009, have just been announced in this week’s issue of Science as the first feathered dinosaurs to be found in the Americas. The finds may suggest new places to look for feathered dinosaurs, since these were found in stone previously thought to be too coarse for the preservation of feathers. And they may also, along with a newly re-examined specimen found in 1995, provide insight into what role feathers played for animals that did not use them for flight…

The search for more feathery fossils has already begun. “I’ve been out this summer looking for more, and the museum is probably looking as well. I’m sure lots of people will be looking once this paper comes out,” Zelenitsky says. “And I think people will start looking through their collections, and start preparing fossils that haven’t been prepared.”

At least now we know that you can find feathered dinosaurs anywhere, Therrien says. And he emphasizes that people will have to be careful: “If it hadn’t been for that lucky break, I’m convinced that we would have never found those feathers. We would have just prepared through them.” In this case, preparing through them would have meant losing them–and losing a discovery too.

Another unintended consequence – though motivated by curiosity about what might be found by varying the technique.

Thanks, Ursarodinia

Fossil finger points to a previously unknown human relative


East Gallery of the Denisova Cave

A 30,000-year-old finger bone found in a cave in southern Siberia came from a young girl who was neither an early modern human nor a Neanderthal, but belonged to a previously unknown group of human relatives who may have lived throughout much of Asia during the late Pleistocene epoch. Although the fossil evidence consists of just a bone fragment and one tooth, DNA extracted from the bone has yielded a draft genome sequence, enabling scientists to reach some startling conclusions about this extinct branch of the human family tree, called “Denisovans” after the cave where the fossils were found…

By comparing the Denisovan genome sequence with the genomes of Neanderthals and modern humans, the researchers determined that the Denisovans were a sister group to the Neanderthals, descended from the same ancestral population that had separated earlier from the ancestors of present-day humans. The study also found surprising evidence of Denisovan gene sequences in modern-day Melanesians, suggesting that there was interbreeding between Denisovans and the ancestors of Melanesians, just as Neanderthals appear to have interbred with the ancestors of all modern-day non-Africans.

The story now gets a bit more complicated,” said Richard Green, an assistant professor of biomolecular engineering in the Baskin School of Engineering at UC Santa Cruz. “Instead of the clean story we used to have of modern humans migrating out of Africa and replacing Neanderthals, we now see these very intertwined story lines with more players and more interactions than we knew of before.”

The Denisovans appear to have been quite different both genetically and morphologically from Neanderthals and modern humans. The tooth found in the same cave as the finger bone shows a morphology that is distinct from Neanderthals and modern humans and resembles much older human ancestors, such as Homo habilis and Homo erectus. DNA analysis showed that the tooth and the finger bone came from different individuals in the same population.

It is not clear why fossil evidence had not already revealed the existence of this group of ancient human relatives. But Green noted that the finger bone was originally thought to be from an early modern human, and the tooth resembles those of other ancient human ancestors. “It could be that other samples are misclassified,” he said. “But now, by analyzing DNA, we can say more definitively what they are. It’s getting easier technically to do this, and it’s a great new way to extract information from fossil remains.”

Fascinating work. Think about this sort of research as a career or at least an avocation. Do your species some good with your spare time.

Knocking down a few beers while naming your new dinosaur

When Nicholas Longrich discovered a new dinosaur species with a heart-shaped frill on its head, he wanted to come up with a name just as flamboyant as the dinosaur’s appearance. Over a few beers with fellow paleontologists one night, he blurted out the first thing that came to mind: Mojoceratops.

“It was just a joke, but then everyone stopped and looked at each other and said, ‘Wait — that actually sounds cool,’ ” said Longrich, a postdoctoral associate at Yale University. “I tried to come up with serious names after that, but Mojoceratops just sort of stuck.”

With the publication of Longrich’s paper describing his find in the Journal of Paleontology…the name is now official…

It was only after coming up with the unusual name that Longrich looked into its etymology. Surprisingly, he found that it was a perfect fit for the species, which sported a flamboyant, heart-shaped frill on its head.

“I discovered that ‘mojo’ is an early 20th-century African-American term meaning a magic charm or talisman, often used to attract members of the opposite sex,” he said. “This dinosaur probably used its frill to attract mates, so the name made sense.” The full name is Mojoceratops perifania, with “perifania” meaning pride in Greek. (The other part of the name mojoceratops follows the convention of other related species, with “ceras” being Greek for horn and “ops” being Greek for face.)

While all ceratopsids have frills on the tops of their skulls, “Mojoceratops is the most ostentatious,” Longrich said, adding that their frill is also the most heart-shaped of all the related species.

Haven’t been in New Haven in decades; but, I wonder which bar he was drinking in.

You have beaucoup choices. You can hangout near the campus and be surrounded by Yalies. Or wander out into the old neighborhoods like Wooster Street and have some dynamite pizza along with your beer.

More Mojo.