Tag: paleontology

Were the dinosaurs covered by feathers or scales? Scientists disagree.

9:11 am

Were the dinosaurs covered by feathers or scales? Two scientists find that most had scales.

Palaeontologists Paul Barrett of the Natural History Museum in London and David Evans of the Royal Ontario Museum in Toronto created a database of all known impressions of dinosaur skin tissues. They then identified those that had feathers or feather-like structures, and considered relationships in the dinosaurian family tree.

The results, which Barrett revealed at the Society of Vertebrate Palaeontology’s annual meeting in Los Angeles in late October, indicate that although some ornithischians, such as Psittacosaurus and Tianyulong, had quills or filaments in their skin, the overwhelming majority had scales or armour. Among sauropods, scales were also the norm.

The uncertainty of science: Don’t bet any money on this result. The number of dinosaur fossils actually known is relatively tiny — making the overall database tiny as well — and further discoveries could change everything.

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A non-paleontologist documents significant errors in the work of several noted paleontologists.

11:46 am

Dinosaurgate: A non-paleontologist documents significant errors in the work of several noted paleontologists.

About two and half years ago, Dr. Myhrvold came across a 2009 paper by Dr. Erickson as he was trying to answer the question, “Why were dinosaurs big?” He said data in two of the graphs, one plotting the length of the thigh bone versus age, the other mass versus age, conflicted with each other. “I instantly knew that this couldn’t be correct,” Dr. Myhrvold said.

Dr. Myhrvold said he contacted Dr. Erickson, asking for the original data. While Dr. Erickson answered some questions, he said the data was on a computer he had gotten rid of and later that he did not have time to answer more questions, Dr. Myhrvold said.

Dr. Myhrvold was able to obtain some of the data from other researchers and thought he could do a better statistical analysis. Last year, he submitted a paper with his calculations — a fairly esoteric scientific disagreement about how best to extract reasonable generalizations from a limited number of fossils.

Dr. Erickson was one of the reviewers and argued strongly against publication. While praising Dr. Myhrvold’s accomplishments and saying the calculations appeared to be numerically correct, Dr. Erickson said the paper would not advance scientific understanding.

“In fact it will hurt our field by producing inherently flawed growth curves, misrepresenting the work of others, and stands to drive a wedge between labs that are currently cordial with one another,” he wrote. [emphasis mine]

Shades of Phil Jones of Climategate fame, who when asked for his original climate data first stalled, then stonewalled, then admitted that the data had been “lost.” Similarly, like the Climategate scientists who tried to squelch the work and careers of anyone who challenged them, the paleontologist being accused here attempted to prevent the accusation from been published.

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A recently discovered 1.8 million year old skull suggests that the multiple human species theorized by paleontologists were actually just one.

3:39 pm

The uncertainty of science: A recently discovered 1.8 million year old skull suggests that the multiple human species theorized by paleontologists were actually just one. More details here.

It is one of five early human skulls — four of which have jaws — found so far at the site, about 100 kilometers (62 miles) from the capital Tbilisi, along with stone tools that hint at butchery and the bones of big, saber-toothed cats. Lead researcher David Lordkipanidze, director of the Georgian National Museum, described the group as “the richest and most complete collection of indisputable early Homo remains from any one site.”

The skulls vary so much in appearance that under other circumstances, they might have been considered different species, said co-author Christoph Zollikofer of the University of Zurich. “Yet we know that these individuals came from the same location and the same geological time, so they could, in principle, represent a single population of a single species,” he said. The researchers compared the variation in characteristics of the skulls and found that while their jaw, brow and skull shapes were distinct, their traits were all within the range of what could be expected among members of the same species.

I have always thought that paleontologists were too quick to name each new major find as a new species. Among all species there is always a wide variety of features. One person is tall. Another has a big forehead or head. This discovery reinforces this idea. The five skulls were all found in the same place, from the same group. Yet they were very different from each other.

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Scientists have found a fossil of a mosquito with traces of blood in its engorged abdomen.

8:30 am

Scientists have found a fossil of a mosquito with traces of blood in its engorged abdomen.

Although scientists have found fossils of suspected blood-sucking insects, the creatures’ feeding habits have mostly been inferred from their anatomy or the presence of blood-borne parasites in their guts. But Greenwalt’s fossilized mosquito contains molecules that provide strong evidence of blood-feeding among ancient insects back to 46 million years ago. It is a fortunate find. “The abdomen of a blood-engorged mosquito is like a balloon ready to burst. It is very fragile,” says Greenwalt. “The chances that it wouldn’t have disintegrated prior to fossilization were infinitesimally small.”

Some news reports have implied that the scientists had found actual blood 46 million years old. This is not the case. They found “large traces of iron and the organic molecule porphyrin — both constituents of haemoglobin, the oxygen-carrying pigment found in vertebrate blood. These molecules were either rare or absent in the abdomen of a fossilized male mosquito (which does not drink blood) of the same age, found at the same location.” Still, even though this isn’t actual blood, the evidence is good and so the result is quite cool.

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

12:37 pm

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.

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More evidence dinosaurs were warm-blooded

11:57 am

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.”

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