The duck-billed dinosaurs more properly known as hadrosaurs were the most prolific vegetarians of the late Cretaceous period, and researchers think their unusual mouth mechanics may have played a role in their evolutionary success. A new study of the hadrosaur Edmontosaurus examined the animal’s fossilized teeth in unprecedented detail. Using an electron scanning microscope, researchers were able to examine minute scratches on individual dino teeth made by daily wear and tear 65 million to 68 million years ago to test competing theories about how the creatures may have munched [Scientific American].
The mouth of a hadrosaur has been compared to a “cranial Cuisinart,” with hundreds of teeth lined up in rows to chop up the tough plants of the late Cretaceous. But the dinosaurs didn’t have the complex jaw joint that mammals have, leaving scientists to puzzle over exactly how hadrosaurs did all that chewing [MSNBC]. The study, published in the Proceedings of the National Academy of Sciences, found scratches indicating that the movements of a hadrosaur’s teeth was a complicated matter, involving sideways and front to back motions as well as the traditional up and down chomp.
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The latest evidence that the ancient Indonesian “hobbit” was a distinct species of hominid, and not just a deformed pygmy, comes from the soles of its feet. Ever since researchers discovered the fossils of a three-foot-tall hominid with a chimpanzee-sized brain on the Indonesian island of Flores, debate has raged over how to interpret the bones. Now, a new study supports the theory that the hobbit, Homo floresiensis, was a species that split from our human lineage early in evolutionary history, and developed its strange shape in the isolation of the island. Other experts agree that evidence is accumulating that H. floresiensis was, in fact, a bona fide species.
In the new study, published in Nature, researchers found that the hobbit’s foot was surprisingly long in relation to the body, and that it had other ape-like features. The navicular bone, which helps form the arch in the modern foot, was especially primitive, more akin to one in great apes. Without a strong arch — that is, flat-footed — the hominid would have lacked the springlike action needed for efficient running. It could walk, but not run like humans. Weighing the new evidence, the research team led by William L. Jungers … concluded that “the foot of H. floresiensis exhibits a broad array of primitive features that are not seen in modern humans of any body size” [The New York Times].
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Scientists say they have found fossils near the Colorado-New Mexico border that prove some dinosaurs survived the mass extinction that most researchers believe was caused by a meteor impact 65 million years ago. James Fassett, a scientist with the U.S. Geological Survey, says he has found evidence that a sizable population of ceratopsians and sauropods, a class of giant, dim-witted leaf-eaters such as the brachiosaurus, hung on for another 500,000 years in the [San Juan] basin. “There might even have been some T. rexes, based on some teeth we found” [Los Angeles Times], he said.
The bones of hadrosaurs, tyrannosaurs, anklyosaurs, and several other species were found together in a sandstone formation that dates to the Paleocene epoch—the time period after the so-called Cretaceous-Tertiary (K-T) extinction event, which is thought to have killed off the dinosaurs [National Geographic News]. To prove that the bones he found were indeed older than the extinction and eliminate the possibility that they had not simply been incorporated into newer rocks, Fassett points to his discovery of 34 bones from a single hadrosaur: If they had been washed away from their original location, they would almost certainly have been separated, not found together [Los Angeles Times].
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Continuing the controversy over whether tissue can be extracted from fossils, cell-like structures resembling blood cells have been found in the leg bone of a dinosaur excavated from a Montana site. The researchers, led by Mary Schweitzer, have sequenced a set of proteins belonging to the 80-million-year-old remains of a duck-billed hadrosaur…. confirmed the presence of collagen, laminin and elastin proteins from the bone…. [and] independently verified amino acids in dinosaur tissues [GenomeWeb].
In 2007, Schweitzer first reported finding soft tissue, and then collagen, from the leg bone of a 68-million-year-old Tyrannosaurus rex excavated two years prior. But her team’s research later proved controversial, with some questioning whether the samples they had obtained had become contaminated with proteins from modern species [Nature News]. So the team set out to replicate its findings, and searched for dinosaur fossils buried in deep sandstones, which were likely to be well preserved, and they speeded up the process of getting them from the field to the lab [Cosmos].
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On a rocky island high in the Canadian arctic, paleontologists have unearthed the fossilized remains of a versatile, web-footed creature that could prowl over land and paddle in the water, and researchers say it represents a “missing link” in the evolution of seals, sea lions, and walruses. Those animals all belong to a group called pinnipeds, or fin-footed mammals, which are descended from land-living ancestors and evolved flippers in place of limbs as they adapted to water. This evolutionary process has been difficult to study precisely because the earliest known pinniped … already had flippers, and scientists did not have access to transitional forms in the fossil record [Times Online].
Now, the new discovery of the nearly complete fossil skeleton helps fill in the evolutionary gap. Researchers named the creature Puijila darwini (”pew-YEE-lah dar-WIN-eye”). That combines an Inuit word for “young sea mammal,” often a seal, with an homage to Charles Darwin. The famed naturalist had written that a land animal “by occasionally hunting for food in shallow water, then in streams or lakes, might at last be converted into an animal so thoroughly aquatic as to brave the open ocean” [AP].
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A new study of fossilized coral reefs in Mexico has revealed that sea levels have risen abruptly in past epochs, which researchers say supports the theory that ocean levels could rise dramatically again in response to global warming. The study suggests that a sudden rise of 6.5 feet to 10 feet occurred within a span of 50 to 100 years about 121,000 years ago, at the end of the last warm interval between ice ages. “The potential for sustained rapid ice loss and catastrophic sea-level rise in the near future is confirmed by our discovery of sea-level instability” in that period, the authors write [The New York Times].
Other researchers have previously found evidence of rapid sea level rise as ice ages gave way to more temperate eras, causing vast ice sheets to melt. But because the coral shows evidence from a warmer interglacial period—similar to the one we’re in currently—the find boosts the chances that today’s melting ice sheets could trigger rapid sea-level rise, the study authors say [National Geographic News]. However, not everyone is convinced that the authors have proven their case. Some experts argue that the researchers haven’t definitively shown that the coral fossils date from 121,000 years ago.
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The first sea creatures to venture onto land may have been temporary visitors who protected themselves on the dangerous trip with borrowed armor, according to a new study. Fossil tracks discovered on an ancient Cambrian-period beachhead suggest an intrepid group of aquatic scorpion-like creatures commandeered empty mollusk shells, much like modern day hermit crabs. Researchers think they used the shells as protection against the harsh dry air, and stole ashore under cover of darkness to graze on mats of algae exposed during low tide [Discovery News].
Much scientific attention has focused on the water-to-land transition that vertebrates made between 385 million and 376 million years ago…. But by that era, another group of creatures — arthropods, the group that today includes crustaceans, scorpions and insects — had been strolling around on land for more than 115 million years [Science News], notes lead researcher James Hagadorn. The tracks he studied, which date from about 500 million years ago, appear to have been made by a many-legged arthropod distantly related to scorpions and horseshoe crabs.
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In the Cambrian Period, one of the mightiest predators cruising the primeval oceans was a critter about the size of a lobster, researchers say, and it wouldn’t win any beauty contests: “The animal is very strange looking” [New Scientist], says Allison Daley, coauthor of a new study. But even though it measured only about one and a half feet in length, it had enough natural weaponry to dominate the marine food chain about 505 million years ago. “This mouth is kind of nasty. I always use the analogy of a pencil sharpener,” said [study coauthor] Jean-Bernard Caron…. “You put anything into this and you get the prey completely cut and broken into pieces” [Toronto Star].
It took researchers several years of combing through fossils to piece together the bizarre jigsaw puzzle that is Hurdia victoria – an ancestor of arthropods such as insects, spiders and crustaceans…. The first fossilised scraps of Hurdia were discovered in 1912. These were followed by further body parts that were so varied and unusual that they were incorrectly classified as either jellyfish, sea cucumbers or shrimp-like crustaceans [The Independent]. The breakthrough came when paleontologists rediscovered a nearly complete fossil that had been found in the Canadian Rockies almost one hundred years ago, and realized the earlier fragments were all parts of the same species.
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A clever and painstaking new analysis has revealed that the famous Homo erectus fossil known as Peking Man is 200,000 years older than previously thought. The fossil, discovered almost a century ago during excavations of the Zhoukoudian caves near Beijing, is now thought to be about 750,000 years old. The revised date could change the timeline and number of migrations of the Homo erectus species out of Africa and into Asia [LiveScience].
Homo erectus were the first hominids to leave the evolutionary cradle of Africa. The species had a distinctive barrel-shaped torso and stood [57 to 70 inches] tall, walking upright in a similar way to modern humans [Nature News]. Researchers had previously suggested that one wave of Homo erectus wayfarers migrated out of Africa between 2 million and 1.6 million years ago, settling Indonesia and southern Asia first before moving northward. But new fossil discoveries, coupled with the new dating of Peking Man, are forcing paleoanthropologists to rethink this scenario.
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In a shale deposit in Kansas, researchers unearthed the intact skull of a prehistoric fish with a surprise inside: the oldest brain ever discovered. The fossilized brain dates from 300 million years ago, and was found in the skull of a fish called an iniopterygian, an relative of sharks and another latter-day species called the ratfish. Iniopterygians were once commonplace in the world’s oceans, living in shallow and muddy marine waters. They measured 50 centimetres (20 inches) at most [AFP].
Researchers were surprised and thrilled by the unexpected discovery. Other soft tissue fossils, such as muscles and kidneys, have been found that date back longer than 350 million years ago, but because the brain is delicate and consists mostly of water, it’s much less likely to be preserved in fossil form, says study co-author John Maisey…. In the fossilization process, the brain itself was replaced with hard minerals, which preserved the shape of the original organ, and the rest of the cavity was filled with sediment, Maisey says. [Scientific American].
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The ancestors to modern humans really hit their stride 1.5 million years ago. Fossilized footprints found in Kenya were made by hominids that share a common foot anatomy and walking stride with modern humans, researchers say.
Scientists are almost certain that the 1.5-million-year-old prints belong to Homo erectus and that the individuals had heels, insteps and toes almost identical to those in humans, and they walked with a long stride similar to human locomotion…. The prints helped explain fossil and archaeological evidence that erectus had adapted the ability for long-distance walking and running [The New York Times]. There is evidence of a heavy landing on the heel with weight transferred along the outer edge of the foot, progressing to the ball of the foot and lifting off with the toes [BBC].
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In a coal mine in Colombia, researchers have unearthed the fossilized remains of the mother of all snakes, a nightmarish tropical behemoth as long as a school bus and as heavy as a Volkswagen Beetle [Los Angeles Times]. The new species, named Titanoboa cerrejonensis, is related to modern boa constrictors, but those descendants are puny in comparison to their primordial ancestor. Titanoboa grew up to 43 feet long and weighed about 2,500 pounds, researchers say, making it the largest snake on record.
The researchers used a known mathematical relationship between the size of vertebrae and the length of the body in living snakes to estimate the size of the ancient animal [BBC News]. Researchers say the ancient boa lived in the wet, tropical rainforest about 60 million years ago, and may have dined on giant turtles and primitive crocodiles–the fossilized remains of those animals were found near the snake fossils. But the extinct snake isn’t just interesting because of its superlative size; researchers also used it to investigate the Earth’s climate in the snake’s day.
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Anthropologists have conducted a new analysis of skulls from the so-called “hobbit” fossils found in an Indonesian cave in 2003, and say their results add more evidence that the fossils come from a hitherto unknown race of tiny people. The researchers compared the hobbit skulls to those of modern humans and apes, as well as the fossil brain cases of early human ancestors. “The shape of the skull is consistent with what we would expect for a small archaic Homo,” said Karen Baab [National Geographic News], lead author of the new study.
When paleontologists unearthed a cluster of strange, hominid skeletons on the island of Flores, they had little idea that they were about to start a fierce debate that would divide the field of anthropology. But soon the researchers declared that the 18,000-year-old fossils came from people who were only three feet tall, and who were actually a different species of hominid, which researchers called Homo floresiensis. “These hobbits – hominids – appear to have survived when modern humans were all over the Earth at this time,” Baab said [The Guardian]. Since then, debate has raged over whether the hobbits were indeed an unknown species, or whether the individuals found in the cave were just modern humans with a disease that stunted their growth and gave them small brains, a condition called microcephaly.
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For feathered dinosaurs, it appears that fashion came before function. A new study of a dinosaur fossil found in northeast China has revealed that the dinosaur, Beipiaosaurus, not only had the soft downy feathers that have been spotted in other fossils, it also had a more primitive type of feather that appears to have been used only for peacock-like displays. These primitive feathers don’t cover the dinosaur’s entire body, they’re found only on the creature’s head, neck and tail. The filaments couldn’t have generated lift, so they’re not flight worthy, and they’re too sparse to have retained the creature’s body heat. [Lead researcher Xing] Xu and his colleagues therefore speculate that the filaments served as display structures, just as many similarly placed feathers do on modern birds [Science News].
The feathers detected on the Beipiaosaurus, which lived in the Cretaceous Period, have a very basic structure. The modern-day feathers sported by birds are elaborate constructions with numerous fibers that branch out from a central filament and hook together. This arrangement is so complicated that many scientists theorize it could have evolved only once…. But paleontologists have proposed that a variety of simpler structures — including peculiar, branched structures colloquially called “dinofuzz” — evolved before feathers [Science News]. The new discovery reveals an even earlier piece of the evolutionary puzzle: the proto-feathers that Beipiaosaurus sported on its head, neck and tail are long filaments without any branches.
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Paleontologists have taken another hard look at the fossilized remains of an arachnid that lived 386 million years ago, and have stripped away its title as the oldest known spider. The creature, Attercopus fimbriunguis, was originally believed to have the capacity to spin webs out of silk, but a reconsideration of the fragmented fossil has led researchers to conclude that Attercopus could make silk, but probably excreted it in sheets. These proto-spiders may have used sheets of silk to line burrows, wrap eggs or even to have sex [Nature News].
Previous studies had suggested that the Attercopus had a single spinneret, the appendage that spiders use to weave silk into webs. But lead researcher Paul Selden studied newly discovered fossil fragments and realized that those previous researchers were mistaken. The tiny hollow hairs that excrete spun silk, called spigots, are arranged in a double row on plates lining Attercopus’s belly, and what had been identified as a spinneret was actually a plate folded over. Without spinnerets, the creatures could not have precisely controlled the emerging silk. “It would have been much less manoeuvrable,” says Selden [Nature News].
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