Tag Archives: fossils

The Earth’s oldest fossil?

The uncertainty of science: Geologists this week announced the discovery of what they think is the Earth’s oldest fossil, approximately 3.7 billion years old.

While the press as usual is going gaga over this announcement, it should be noted that many others in the field have expressed significant doubts.

But the discovery involves some of the most physically tortured rocks on Earth, which have been squeezed and heated over billions of years as crustal plates shifted. The pressure and heat recrystallizes the rocks, erasing much of the fine-scale detail that researchers normally use to identify fossilized stromatolites — so the work is already triggering heated debate. “I’ve got 14 queries and problems that need addressing before I’ll believe it,” says Roger Buick, a geobiologist at the University of Washington in Seattle.

New human species found?

The uncertainty of science: Scientists in South Africa think they have found fossils of a new human species.

In the end, the work of more than 60 researchers yielded a picture of “a relatively tall, skinny hominid with long legs, humanlike feet, with a core and shoulder that is primitive,” Berger says. Some body parts have come into sharper focus than others. In an analysis of the remarkably complete hands, paleoanthropologist Tracy Kivell of the University of Kent in the United Kingdom found that bones in the wrist were shaped like those in modern humans, suggesting that the palm at the base of the thumb was quite stiff. That would allow forces to dissipate over a larger area of the hand than in more primitive humans—a trait associated with tool use. At the same time, H. naledi had a weird thumb and long, curving fingers, as if it still spent a lot of time climbing.

The story of the discovery is interesting in that the fossils were found in a cave in a room that is very difficult to access, so difficult that the scientists themselves have never seen the site. Instead, they have sent very small cavers inside to do the fossil gathering.

There are many caveats to this story. The 15 skeletons appear different than humans, but to then create a whole human species from this single location is a bit risky.

I think the biggest mystery about this find involves its location. How the heck did these 15 individuals get trapped in this room at the back of a cave that requires you to squeeze down a vertical 100-foot chute only about 8 inches wide to enter?

Did some dinosaur soft tissues survive fossilization?

The uncertainty of science: New research strongly suggests that within dinosaur fossils are found many preserved soft tissues from when the creature was still living.

As early as the 1970s, researchers captured images of what looked like cellular structures inside dinosaur fossils. But did the structures contain actual tissue? Proteins commonly decay hundreds to thousands of years after an organism dies, but in rare cases they have been known to survive up to 3 million years. In a series of studies beginning a decade ago, a team led by North Carolina State University paleontologist Mary Schweitzer reported that they had extracted what appeared to be collagen, the most abundant protein in bone, from a 68-million-year-old T. rex fossil. They sequenced fragments of the protein and concluded that it closely matched that of birds, dinosaurs’ living descendants (see here and here). But other teams haven’t been able to replicate the work, and others suggested that the collagen could be contamination.

The new study, led by materials scientist Sergio Bertazzo and paleontologist Susannah Maidment, both of Imperial College London, has a different strategy for hunting down ancient proteins. Bertazzo, an expert on how living bones incorporate minerals, uses a tool called a focused ion beam to slice through samples, leaving pristine surfaces that are ideal for high-resolution imaging studies. He teamed up with Maidment to apply the technique to eight chunks of dinosaur toe, rib, hip, leg, and claw.

What they found shocked them. Imaging the fresh-cut surfaces with scanning and transmission electron microscopes, “we didn’t see bone crystallites” as expected, Maidment says. “What we saw instead was soft tissue. It was completely unexpected. My initial response was these results are not real.” [emphasis mine]

It must be noted that the new research depends on many uncertainties that still need to be replicated or confirmed.

Ancient fossils on Mars?

A close look at features on the Martian surface seen by Curiosity suggests to one scientist the presence of ancient fossils of carpet-like microbiology.

On Earth, carpet-like colonies of microbes trap and rearrange sediments in shallow bodies of water such as lakes and costal areas, forming distinctive features that fossilize over time. These structures, known as microbially-induced sedimentary structures (or MISS), are found in shallow water settings all over the world and in ancient rocks spanning Earth’s history.

Nora Noffke, a geobiologist at Old Dominion University in Virginia, has spent the past 20 years studying these microbial structures. Last year, she reported the discovery of MISS that are 3.48 billion years old in the Western Australia’s Dresser Formation, making them potentially the oldest signs of life on Earth.

In a paper published online last month in the journal Astrobiology (the print version comes out this week), Noffke details the striking morphological similarities between Martian sedimentary structures in the Gillespie Lake outcrop (which is at most 3.7 billion years old) and microbial structures on Earth.

Noffke is very careful in her analysis. She doesn’t claim any proofs, only that her expert eye sees the same things on both planets. Most intriguing.

Archeologists are disputing the age of a jawbone found in a cave in England.

The uncertainty of science: Archeologists are disputing the age of a jawbone found in a cave in England.

Both sides of the debate agree that there is a lot riding on the outcome. “What is at stake is the entire [prehistory] of Neandertals and early modern humans in Europe,” Pettitt says. Apart from the Kents Cavern fossil and some 43,000- to 45,000-year-old teeth from Italy whose status as modern human or Neandertal is currently also debated, the oldest undisputed human fossils in Europe are about only 40,000 years old and come from a site in Romania. If modern humans really made it all the way to northwest Europe by 41,500 years ago or even earlier, it would mean that they entered Europe much earlier than once thought and also spread across the continent very rapidly. It would also increase the overlap between modern humans and the Neandertals, who already lived in Europe, and who went extinct sometime between 40,000 and 35,000 years ago. What’s more, such an overlap could make it more likely that Neandertals, who made sophisticated ornaments and tools in their last years, copied these techniques from modern humans rather than inventing them on their own.

Evidence from a cave in Australia suggests that humans were doing deep sea fishing more than 40,000 years ago

New evidence from a cave in Australia suggests that humans were doing deep sea fishing — with the sophisticated maritime skills such ocean-going requires — far earlier than previously believed, as much as 42,000 years ago.

More evidence dinosaurs were warm-blooded

A new study has found new evidence that dinosaurs were warm-blooded and active, unlike modern reptiles. Even more surprising,

“The dinosaurs appeared to be even more active than the mammals. We certainly didn’t expect to see that. These results provide additional weight to theories that dinosaurs were warm-blooded and highly active creatures, rather than cold-blooded and sluggish.”

Scientists discover treasure trove of fossils in limestone layer in China

Scientists have discovered a treasure trove of 250-million-year-old fossils in limestone layer in China. Key quote:

The 50-foot-thick (16 meters) layer of limestone that held these fossils dates back to when south China was a large island just north of the equator with a tropical climate. A smattering of fossil land plants suggest this marine community lived near a conifer forest. The fossils are exceptionally well-preserved, with more than half of them completely intact, including soft tissues. Apparently they were protected across the ages by mats of microbes that rapidly sealed their bodies off from decay after death.