Paleontology news

The most famous member of this species is Lucy, an adult female skeleton discovered in 1974 and nicknamed after a Beatles song. Lucy lived about 3.18 million years ago and was fully capable of walking and running on two legs.

9. Australopithecus africanus

A. africanus was an early descendent of Lucy and lived in Southern Africa between 2 million and 3 million years ago. Its brain was larger than Lucy's and its facial features were more human-like.

8. Paranthropus aethiopicus

This early ape-like hominid walked on two legs and lived between 2.8 million and 2.2 million years ago. Based on skull measurements, scientists concluded this species had the smallest adult hominid brain ever discovered.

7. Paranthropus bosei

If P. bosei and its relatives weren't such picky eaters, we might not be here to wonder about them. They split from the line leading to modern human some 2 million years ago and lived alongside our ancestors for millions of years, but died out after failing to adapt their diets.

6. Homo habilis

Many scientists believe H. habilis is the missing link between the ape-like hominids like Lucy and the more human-like ones that came after. It had long ape-like arms but walked on two feet and was capable of creating crude tools.

5. Homo ergaster

Scientists can't decide whether this African hominid is just a failed predecessor of H. erectus or the rightful ancestor of modern humans. It had a thinner skull than H. erectus and was more proficient at making tools and using fire.

4. Homo erectus

For H. erectus, it may have paid to be dense. According to one theory, males rammed each other with their thick skulls in order to win females. H. erectus is generally believed to be the direct ancestor of modern humans and also the first hominid to live in caves and tame fire.

3. Homo floresiensis

It turns out those Floresians were actually on to something. For centuries, their mythology described a race of very small human-like creatures called the Ebu Gogo. Hardly anyone took them seriously, however, until 2003, when word broke that a new species of diminutive hominids was discovered on the Indonesian island.

2. Cro-Magnon

These people looked identical to modern humans and lived in Europe between 35,000 and 10,000 years ago. Their cave paintings and sculptures are the earliest known examples of art by a prehistoric people.

1. Neanderthal

Stocky and squat and well suited for the cold, Neanderthals looked distinctly different from modern humans. But they were like us in other ways: they buried their dead, cared for their sick and injured and may have been capable of language and music. Scientists recently put together a complete Neanderthal skeleton and are working on the genome.

credited to livescience.com

Large size and a fast bite spelled doom for bony fishes during the last mass extinction 65 million years ago, according to a new study to be published March 31, 2009, in the Proceedings of the National Academy of Sciences.

Today, those same features characterize large predatory bony fishes, such as tuna and billfishes, that are currently in decline and at risk of extinction themselves, said Matt Friedman, author of the study and a graduate student in evolutionary biology at the University of Chicago.

"The same thing is happening today to ecologically similar fishes," he said. "The hardest hit species are consistently big predators."

Studies of modern fishes demonstrate that large body size is linked to large prey size and low rates of population growth, while fast-closing jaws appear to be adaptations for capturing agile, evasive prey—in other words, other fishes. The fossil record provides some remarkable evidence supporting these estimates of function: fossil fishes with preserved stomach contents that record their last meals.

When an asteroid struck the earth at the end of the Cretaceous about 65 million years ago, the resultant impact clouded the earth in soot and smoke. This blocked photosynthesis on land and in the sea, undermined food chains at a rudimentary level, and led to the extinction of thousands of species of flora and fauna, including dinosaurs.

Scientists had speculated that during that interval large predatory fishes might have been more likely than other fishes to go extinct because they tended to have slowly increasing populations, live more spread out, take longer to mature, and occupy precarious positions at the tops of food chains. Today, ecologically similar fishes appear to be the least able to rebound from declining numbers due to overfishing.

To build the database he needed to test this prediction, Friedman traveled around the world measuring the body size and jaw bones of 249 genera of fossil fishes that lived during the late Cretaceous. These kinds of direct measurements are possible in fossil fishes because many are represented by complete, articulated individuals. This is unlike the fossil record of most other vertebrates, where bones, teeth and other parts of the skeleton are often scattered and found in isolation.

This study is the first to test this theory with hard data and to quantify the relationship between body size, jaw function and vulnerability of fishes during the Cretaceous extinction, according to Friedman.

"Anyway you sliced it, the data showed that if you were a big fish with a fast bite you were toast," he said.

Ironically, today's large fishes with fast bites evolved relatively shortly after the end-Cretaceous extinction, apparently filling the functional and ecological roles vacated by the victims of that mass extinction. Although the two groups of fishes are not related to each other, their fates may end up being similar.

The paper is called "Ecomorphological selectivity among marine teleost fishes during the end-Cretaceous extinction" and will appear in issue 13 of PNAS. In it, Friedman describes the results of his study as robust because the large-bodied, predatory fishes that are disproportionately devastated also have the best fossil records. "In other words, we can be convinced that these forms really do die off here, and that their disappearance can't be chalked up to a lousy fossil record," Friedman noted.

Nevertheless, fossil fishes are not well studied because paleontologists, as a group, tend to be drawn to other animals, such as dinosaurs. Therefore, many large-scale patterns of fish evolution remain unclear.

The fossil fishes included in the study are diverse in form, and range in length from about 20 feet to less than one inch.

"This study demonstrates that fossil datasets are germane to modern diversity and evolution by allowing us to calibrate what characteristics might relate to extinction vulnerability today," Friedman said. "Echoes of the end-Cretaceous extinction reverberate 65 million years later."

credited to eurekalert.org

Unraveling the origins of agriculture in different regions around the globe has been a challenge for archeologists. Now researchers writing in the Proceedings of the National Academy of Sciences report finding evidence of early human experiments with grain cultivation in East Asia. They gathered this information from an unlikely source―dog and pig bones.

The bones come from a Neolithic site known as Dadiwan, in China's western Loess Plateau, excavated first by a Chinese team in the late 70s and early 80s, and in 2006 by a team from the University of California, Davis, and Lanzhou University in China. Humans occupied the site during two main phases, from 7,900 to 7,200 years ago (Phase 1) and from 6,500 to 4,900 years (Phase 2). Though some fossil remains of millet plants have been found in both of these deposits, the fossils don't directly reveal how much millet contributed to the local diet.

To address this question, the researchers turned to a technique known as stable isotope analysis. Atoms of elements such as carbon come in different forms (isotopes) which are chemically similar, but can be distinguished in the laboratory by minute differences in their mass. Certain kinds of plants known as C4 plants tend to concentrate heavier carbon isotopes as they grow, compared to other plants known as C3 plants. Animals with diets high in C4 plants also tend to concentrate heavier isotopes in their bones. As it turns out, millet is one of the few C4 plants that grow in arid northwest China, making the carbon isotopes in bone a good indicator of a millet-rich diet.

The researchers found that the most of the dog bones from the Phase 1 deposits bore the isotopic signature of a high millet diet. This suggests that these dogs were domesticated and fed by humans who harvested millet. Bones of pigs from the site tell a slightly different story. In the Phase 1 deposits, the pig bones don't show signs of millet in the diet, so they were probably wild pigs hunted and eaten by people. But pig bones from Phase 2 do have the isotopic signature of millet, so they were probably domesticated by this time.

"Our results help fill in the picture of how agriculture arose in this part of the world," says Newsome. "There has been speculation that agriculture spread north from southern rice-farming areas, but the Phase 1 people were likely experimenting with agriculture by cultivating local grains. This simple system was later replaced by people in Phase 2 who had a much more developed agricultural system"

credited to Carnegie Institution (2009, March 29). Early Agriculture Left Traces In Animal Bones. ScienceDaily. Retrieved March 30, 2009, from http://www.sciencedaily.com­/releases/2009/03/090324081439.htm

Discovering a new dinosaur is always exciting, but one particular meat-eating beast has given scientists a major new clue in the mystery of how birds evolved the ability to fly. The new dinosaur, named Aerosteon, seems to have had a unique breathing system that birds likely inherited through evolution.

“It allows birds to fly higher than anything else, and it was obviously present in these dinosaurs,” says Paul Sereno, the University of Chicago paleontologist who discovered the new species.

As they wrote in the journal "PloS One," Aerosteon’s bones are hollow. This is a major new link to birds.

In birds, hollow bones don’t just help them fly by making them lighter, they also help them breathe a lot more efficiently. The bones contain hollow chambers, or air sacs, that act as a kind of secondary lung system. As a bird breathes, half of the inhaled air is passed through the lungs and into one set of air sacs, while the other half passes directly into another set of sacs. When a bird exhales, air is passed from the sacs directly out of the trachea, without lingering in the lungs. The system functions so that air only passes in only one direction, preventing carbon dioxide-rich exhaled air from mixing with oxygen-rich inhaled air, as it does in mammal’s lungs.

Sereno says the fossil evidence indicates the same might have been true for Aerosteon, which roughly translates to "air bones."

"What was really key was some of the bones around the rib cage of the animal, bones that only in birds are invaded by air sacs from the lungs,” says Sereno. “Having found these air pockets in Aerosteon, we reasoned that we really have to accept that Aerosteon and other predatory dinosaurs, likely feathered, these dinosaurs likely breathed like birds.”

While Aerosteon might have breathed like a bird, it certainly couldn’t fly. But it’s discovery is helping to put the theory that birds evolved from dinosaurs on more solid ground.

Dino Hunting

Sereno and his team found the 80-million-year-old giant in the badlands of Argentina, an area known as Patagonia.

Eighty million years ago, in the Cretaceous period, the area would have been richly forested, with many flowing rivers and a vibrant ecosystem. Today, that same area is a hot, dry, almost desert-like environment. Not so great for a giant hungry dinosaur, but the perfect conditions for finding fossils.

Even in the right conditions, finding one particular fossil can be daunting. Paleontologists can spend weeks searching for a substantial find. As Sereno describes, “Any find, in hindsight, almost looks like an accident, because you go out into the area, it’s a vast area, and somehow you have to pull out a needle out of a haystack.”

One specific needle was particularly important: Aerosteon’s teeth. By examining the teeth of a dinosaur, a paleontologist can determine a lot about its lifestyle, eating habits, and what other species it is most closely related to. Judging from Aerosteon’s teeth, Sereno believes the theropod, or three-toed predatory dinosaur, could be a distant descendant of the fearsome Allosaurus. This fact is startling in and of itself, as the allosaurs were thought to have died out in South America long before the emergence of this new species. How did Aerosteon survive?

Sereno explains that, “Pangaea, the great supercontinent, which was the birthplace of dinosaurs, had broken apart, and South America was largely isolated onto its own. The Atlantic Ocean was narrower, but it was not connected to any other land masses.”

He believes the ancestors of Aerosteon were isolated to South America, surviving long after their relatives on the other continents died out due to competition from more advanced predators, like the tyrannosaurs.

And what would the Aerosteon have looked like? Sereno describes it as “an animal that’s about 30 feet long, would have been 2 legged, would probably have weighed about as much as an Indian Elephant.”

Although the dinosaur would have seemed impressively large to us, there are a number of predatory dinosaurs, like Tyrannosaurus Rex for example, which were significantly bigger. But what amazed Sereno wasn’t the creature’s size; for him it was all about the hollow bones.

So the next time you see a bird on the wing, remember that it’s flying, and breathing, courtesy of the dinosaurs.

credited to sciencentral.com

The end of an era Some 65 million years ago, the earth's most recent 'mass extinction' took place. One or more catastrophic events - such as a comet strike or increased volcanic activity - produced widespread fires and clouds of dust and smoke that obstructed sunlight for a long period of time. These adverse conditions killed off about 60% of the plant species and numerous animals, including the dinosaurs. Only the most well-adapted plants and animals were able to survive this mass extinction - but what is 'most well-adapted'?

A role for DNA duplication?

Jeffrey Fawcett, Steven Maere and Yves Van de Peer (VIB-UGent) have been working as bioinformatics specialists to decode various plant genomes - the complete content of a plant's DNA - ranging from small weeds to tomatoes and rice to trees. Time and again, they have been confronted with the fact that, over the course of the history of these plants, their entire DNA was duplicated one or more times. By means of sophisticated research techniques, they have dated these duplications as closely as possible.

Yves Van de Peer's group then noticed that the most recent duplications occurred at approximately the same time in all of the plants. But, in terms of evolution, 'the same time' is relative: the DNA duplications occurred between 40 and 80 million years ago. So, the bioinformaticians worked to refine the dating. Thanks to their expertise in comparative genome studies and their extensive database, they were able to make a very precise dating of the duplications on the basis of standard evolution trees. This indicated that, in all of the plants under study, the most recent genome duplication occurred some 65 million years ago - thus, at the time of the last mass extinction.

A universal mechanism

From these results, the VIB researchers concluded that plants with a duplicated genome were apparently the 'most well-adapted' for survival in the dramatically changed environment. Normally, in unaltered circumstances, duplications of DNA are disadvantageous. In fact, they cause very pronounced properties that are not desired in an unaltered environment. However, in radically changed circumstances, these very properties can make the organism better adapted to the new climate.

In previous research, Yves Van de Peer had discovered very old genome duplications in early ancestors of vertebrates and fish. At that time, he showed that these duplications were probably crucial for the development of vertebrates and thus of human beings as well. So, genome duplication is probably a universal mechanism that has ensured that the role of our planet's vertebrates and flowering plants has become much greater over time.

credited to vib.be

Among the hundreds of plants that have been domesticated in the New World, none has received as much attention or been subject to as much debate as corn, or maize (Zea mays L.), arguably the most important crop of the Americas. Controversies have existed for years over what the wild ancestor of maize is and where and when it was domesticated. An international team of scientists led by Dolores Piperno, archaeobotanist at the Smithsonian's National Museum of Natural History, and Anthony Ranere, professor of anthropology at Temple University in Philadelphia, have discovered the first direct evidence that indicates maize was domesticated by 8,700 years ago, the earliest date recorded for the crop. The research findings will be published March 23 in the journal, Proceedings of the National Academy of Sciences.

It is certain that maize was originally domesticated in Mexico from a wild plant called "teosinte," and genetic studies of modern populations of teosinte and maize suggested this event occurred somewhere in the Central Balsas Valley region of tropical southwest Mexico. However, no research on early prehistoric human settlement and agriculture had been carried out there. Piperno and the team searched this region of Mexico for locations that showed human occupancy for the time period they thought to be critical to maize domestication, from approximately 8,000 to 9,000 years ago. They discovered sites dating to this age, excavated them and analyzed the stone tools and plant remains they retrieved. Microfossil (starch grain and phytolith) analysis from a rock shelter called Xihuatoxtla, conducted in part with Irene Holst at the Smithsonian Tropical Research provide direct evidence for the domestication of maize and a species of squash.

"Our findings confirm an early Holocene age for maize domestication and indicate that it is another important New World crop that had its origins in the tropical forest," said Piperno. "Much more work needs to be done in the Central Balsas region to investigate even earlier periods when teosinte must have been exploited by early human populations and then initially cultivated."

The evidence corroborates a large quantity of previous research carried out in the lowland tropical forest south of Mexico by Piperno and other investigators that indicated maize spread to Panama approximately 7,600 years ago and was well established in northern South America about 6,000 years ago.

The archaeological record establishes tropical southwest Mexico as an important region where early agriculture occurred in the New World and adds maize to the roster of important cereals (others are wheat and barley from the Middle East) that were cultivated and domesticated by 9,000 years ago. The team's findings also contribute to the growing body of evidence that seasonally dry tropical forests were important centers of early human settlement and farming in the Neotropics. Early agriculture in this region of Mexico appears to have involved small groups of cultivators who were shifting their settlements seasonally and engaging in a variety of subsistence pursuits.

credited to si.edu

Feathered dinosaurs may have been the rule, not the exception. A stunning new fossil from China reveals primitive filamentary feathers on a dinosaur only distantly related to birds, indicating that all dinosaurs share a feathery ancestry.

All of the feathered dinosaurs found since Sinosauropteryx startled the world in 1996 come from a group of two-legged predators called theropods, which gave rise to birds. Now Hai-Lu You of the Institute of Geology in Beijing, China, along with three colleagues, has found feather-like filaments on a fossil named Tianyulong confuciusi (Nature, vol 458, p 333).

About 70 centimetres long, the plant-eating Tianyulong lived from about 140 to 100 million years ago. The fossil is a member of the ornithischian group of dinosaurs that diverged about 220 million years ago from the other main branch of the dinosaurs, which contained the theropods. The presence of feathers on both branches of the evolutionary tree suggests they were present in the ancestor of all the dinosaurs.

If the ancestral form had such filaments, then they might be present in many or most dinosaurs - although skin impressions left by large dinosaurs lack feathers, suggesting that the trait died out in larger species.

Feathers might even stretch back to the pterosaurs, which split from the ancestors of dinosaurs shortly before the dinosaur groups emerged. A few pterosaur fossils possess hair-like stubble.

While modern flight feathers are elaborately branched, the new fossil's feathers are hollow single filaments - "the most primitive basic feather structure", says ornithologist Alan Brush at the University of Connecticut at Storrs. Similar feathers still exist on the tail of the 12-wired bird of paradise and in the "beards" of wild turkeys.

credited to newscientist.com