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A U.S. research published today in the journal ScienceShows that some dinosaurs and reptiles of the Mesozoic (about 250 million years) could see in the dark and be active at night. These results contradict the belief that these animals are only acting in a day due to energy constraints.
“The eyes of these nocturnal animals had a very open pupil determined by the retina and the focal length, which made them eyes with a sensitivity to light very good,” he explains to SINC Lars Schmitz, an author of the study and researcher in the Department of Geology at the University of California (USA).
The researchers analyzed the structure of the eye of 33 archosaurs – ‘ruling reptiles’, among which are the crocodiles and birds-as well as dinosaurs and pterosaurs -’ alados’-lizards of the Mesozoic era.
“We wanted to see if it is true the hypothesis that most dinosaurs were diurnal, while mammals were nocturnal and lived in the ‘shadow’ of dinosaurs,” says Schmitz.
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The fossils used as climatic indicators contain important information about the sharp drop in temperature that took place there 137 million years ago during the interglacial period of the Cretaceous. A sharp drop in temperature at that time was briefly interrupted the balance of the warm climate that prevailed in the geological time. The water temperature in the Arctic Ocean fell from an average of 13 ° C at temperatures between 4 and 7 ° C, so that even the poles were likely to freeze. Elizabeth Nunn, University of Mainz in Rhineland-Palatinate [1] and Gregory Price, of the University of Plymouth in England have examined samples of rocks containing fossils, and belemnite glendonite from Spitzbergen to determine the temperature of the Arctic Ocean between 140 and 136 million years. The reconstruction of paleoclimate can improve predictions about future climate and environmental developments and assess the impact of human activity on climate.
Based on knowledge of the Cretaceous, the dominant climate during this geological period was generally hot with high CO2 levels, although researchers have always assumed the existence of periods of cold intermittent. The analysis performed by two specialists indicates a short cold spell there are 137 million years. Elizabeth Nunn says “it’s really very cold compared to average temperatures of the time (13 to 20 ° C). At the time of the interglacial period of the Cretaceous, dinosaurs inhabited the polar regions also. Although certainly of marine reptiles such as ichthyosaurus and Pliosaurus migrated following the cold spell, scientists wonder how the dinosaurs, they have gotten used to cold conditions.
The rocks of Spitsbergen and Elizabeth Nunn Gregory Price discussed their work, are for the Paleontologists remains of marine deposits ideal for the study of earlier times when the region was still a sea Some strata dating from the Cretaceous lower Valanginian are rich in belemnites, fossils similar to octopus current and fossil glendonite. They have allowed researchers to determine the ratio between two isotopes of oxygen and thus provide an accurate record of ocean temperature at the time. Elizabeth Nunn said that “if it is cold, then the rate of the isotope oxygen-16 immobilized as ice mass increases in ice and the rate of the isotope 18 compared to 16 increases the isotope in the oceans.
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Many features Azendohsaurus are more primitive than previously thought: some characteristics similar to those of dinosaurs, such as feeding on plants, developed independently
A careful analysis Azendohsaurus madagaskarensis Based on the skull to complete rather than just teeth and jaw, lies this species 230 million years old in a very different branch of the evolutionary and primitive reptiles.
Many features Azendohsaurus are in fact more primitive than previously thought, which means that some characteristics similar to those of dinosaurs, such as feed plants, evolved independently.
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The idea that the ancient island of Hateg, Romania, dwarf dinosaurs existed, was proposed a century ago by Baron Franz Nopcsa, whose family owned property in the area. He realized that many dinosaurs had Hateg close evolutionary relatives in ancient rocks from England, Germany and North America, but specimens of Romania had only half the size.
Nopcsa The hypothesis has been validated for the first time in a new work by Professor Mike Benton of the University of Bristol, and six experts from Romania, Germany and the United States. They have found that dinosaurs were really Hateg island dwarfs.
A hotly debated topic among evolutionary ecologist is whether there is an “island rule” whereby the large animals isolated on an island tend to become smaller. There is no doubt that dinosaurs were found in Hateg small, the question was whether such individuals had reached adult size or not.
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An international team of scientists demonstrated, with the discovery in Australia of a hip bone fossilized dinosaur, tyrannosaurus that existed 110 million years ago also in the southern continents. It was thought that only lived in the north. The discovery, which is now published in Science Sheds light on the evolutionary history of dinosaurs.
Scientists at the University of Cambridge (United Kingdom), the Natural History Museum of London (United Kingdom), University of Melbourne (Australia), and the Museum Victoria in Melbourne have identified at the site of Dinosaur Cove in Victoria (Australia) a hip belonging to an ancestor of Tyrannosaurus rex that lived 110 million years ago.
“This is an exciting discovery because until now only been found tyrannosaur fossil in the northern hemisphere and some scientists thought that the tyrannosaur ever existed in the southern hemisphere,” said Roger Benson, the lead author and researcher in the Department of Science Earth, University of Cambridge.
The researchers found a pubic bone 30 inches long with two ends, one flattened and connected to the hip, the other boot-shaped. The study, published this week in ScienceSheds light on the evolutionary history of this group of dinosaurs, and raises the question of why it was only in the northern hemisphere where tyrannosaurs evolved as top predators T. rex.
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The birds are not descended from theropod dinosaurs, according to findings from a new study that challenge accepted theories for decades about the evolution of flight.
The new analysis, published in the journal Proceedings of the National Academy of Sciences, was done with the fossil of a rare specimen discovered in 2003, called Microraptor, in which three-dimensional models were used to study its possible potential flight and concluded feathered species that this small animal must have been a glider, ie could not fly away but simply planning to descend from the branch of a tree or other high point.
The research findings are consistent with a series of studies in recent years, which is a progressive discrediting the theory that birds descended from dinosaurs, according to critics of this theory.
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By an expedition to the Gobi Desert in China, a team of Scientists have verified that a group of dinosaurs, despite sporting a look similar to birds, was independent of them.
The finding extends the fossil record of the family Alvarezsauridae, a rare group of dinosaurs with bird-like a claw in his hand, and arms are too short and strong, distancing birds over the group in the evolutionary tree.
So far, no direct evidence that some dinosaurs this type lived during the Late Jurassic, about 160 ago million years.
This research sheds new light on the little-known development Initial birds in the Late Jurassic in China, to weed out alvarezsauridos as the ancestors of birds.
Jonah Choiniere scientist at George Washington University, has name the newly discovered dinosaur species: Haplocheirus Sollers.
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Scientists have finally recognized as the cause of extinction of ancient lizards drop huge asteroid
Version of that 65 million years ago dinosaurs destroyed fallen to Earth a giant asteroid, was launched by one of the first. However, for many years, researchers still doubt find other explanations for the disappearance of dinosaurs.
For example, put forward an alternative theory about powerful giant volcanic eruptions in India. But in the end, this theory has not withstood scrutiny.
Confirmation of the first asteroid, the version was made based on the most comprehensive review yet of the analysis of available data. The evidence was formally presented to the 41 th annual conference of the lunar and planetary research in the United States.
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The era of the dinosaurs probably lasted at least ten million years longer than paleontologists thought not. On their extinction 65 million years ago (not counting the birds, their direct descendants), nothing changes, then the past on the other hand shifted the birth of the group.
Team of paleontologists from the United States, Germany and South Africa in today’s issue of the journal Nature the discovery of information on an animal closely related dinosaurs that lived 240 million years.
Asilisaurus kongwe among silesaury. Is a group of reptiles closely related to dinosaurs. Authors resemble their relationship to the evolutionary proximity of humans and chimpanzees.
The oldest fossils of dinosaurs come from before 230 million years, the new finding, however, provides evidence that the two related groups of reptiles segregate at least ten million years earlier.
Paleontologists have discovered in southern Tanzania the remains of fourteen kinds of specimens Asilisaurus kongwe, And thus were able to reconstruct a nearly complete skeleton. The animal was two to three meters long and weighed less than thirty pounds. Probably fed plant food, or were among the omnivores.
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Knowing what plants fed the giant dinosaurs to reach its gigantic size is one of the most important puzzles in trying to understand how these huge dinosaurs lived over 100 million years. Scientists at Bonn University have investigated the basis of their diet, the results have been published in the journal Proceedings of the Royal Society B.
We took 200 milligrams of dried and crushed
horsetails, ten milliliters of
gastric juice from sheep’s belly, some
minerals, carbonate and water. They filled a big
glass syringe with this mixture, coupled to a rotating drum and put everything in an oven where the mixture can be slowly turning. This gives a “belly dinosaur” artificial.
With this method, also used as gas production technique of Menke “to assess food for cows,” the researcher Jurgen Hummel
Zoological Sciences Institute of Bonn are researching plants that could have fed over giant dinosaurs 100 million years, as this remains one of the missing pieces in the puzzle of the largest land animals that ever walked this planet.
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Based on knowledge of the Cretaceous, the dominant climate during this geological period was generally hot with high CO2 levels, although researchers have always assumed the existence of periods of cold intermittent. The analysis performed by two specialists indicates a short cold spell there are 137 million years. Elizabeth Nunn says “it’s really very cold compared to average temperatures of the time (13 to 20 ° C). At the time of the interglacial period of the Cretaceous, dinosaurs inhabited the polar regions also. Although certainly of marine reptiles such as ichthyosaurus and Pliosaurus migrated following the cold spell, scientists wonder how the dinosaurs, they have gotten used to cold conditions.
We took 200 milligrams of dried and crushed horsetails, ten milliliters of gastric juice from sheep’s belly, some minerals, carbonate and water. They filled a big glass syringe with this mixture, coupled to a rotating drum and put everything in an oven where the mixture can be slowly turning. This gives a “belly dinosaur” artificial.