News Article | May 2, 2017
Genetic studies of cichlid fishes suggest that interspecies hybrids played a prominent role in their evolution. Analysis of a unique fossil cichlid from the Upper Miocene of East Africa now provides further support for this idea. The cichlids constitute one of the most diverse families of freshwater fishes in tropical habitats. Its members have adapted to the demands of a wide range of ecological niches, and many have developed highly specialized feeding habits. Contemporary representatives of the family therefore provide an ideal model system for evolutionary biologists who seek to understand the mechanisms that underlie the process of species diversification. Unfortunately, fossil specimens that could help to trace earlier phases of cichlid evolution are quite rare, and most are poorly preserved and/or fragmentary. Now scientists around Ludwig-Maximilians-Universitaet (LMU) in Munich paleontologist Professor Bettina Reichenbacher have described a new fossil cichlid discovered in Upper Miocene strata in East Africa, which provides new insights into the evolutionary history of the group. Moreover, the results are consistent with molecular genetic data relating to the ongoing diversification of the family in the Great Lakes region of East Africa, which have indicated that hybridization between members of related species or even genera has played a major role in cichlid speciation. The work also sheds light on the environmental conditions that prevailed in the Rift Valley of East Africa in the Upper Miocene period, 9-10 million years ago. The new findings appear in the Journal of Vertebrate Paleontology. The authors assign the fossil to a newly defined genus and species (Tugenchromis pickfordi). In light of the scarcity of well-preserved cichlid fossils, the phylogenetic placement of the new specimen is dependent on comparisons with modern members of the family -- and given the enormous diversity of the latter, this is by no means an easy task. However, in cooperation with Dr. Ulrich Schliewen (Zoological State Collections, Munich), Reichenbacher and her team have assembled a unique database on the morphology of present-day cichlids, in which all the lineages found in Lake Tanganyika are represented. This dataset is based on the painstaking analysis of X-ray photographs of the skeletons of 763 individuals belonging to 227 modern cichlid species. "This unique resource has made it possible for the first time to place a new fossil species securely within the phylogeny of African cichlids. Indeed, our analysis shows it to be a member of the most ancient cichlid lineage that contributed to the so-called East African Radiation, a spectacular burst of diversification that has given rise to a huge variety of species," Reichenbacher explains. The new fossil displays a striking "mosaic-like" set of characters, combining traits that are typical for three distinct cichlid groups found in Lake Tanganyika today. "This combination of characters is particularly interesting, because molecular geneticists have shown that many of the cichlid species in Lake Tanganyika possess 'mosaic' genomes -- made up of genetic material derived from non-related species. The mosaic of characters displayed by the fossil specimen is a reflection of the morphological consequences of such interspecies hybridization," says Dr. Melanie Altner, first author of the study. The basin now occupied by Lake Tanganyika came into being at least 5.5 million years ago, and it has been assumed that the species radiation that gave rise to the striking diversity of cichlids in the lake was triggered by its formation. However, new models based on molecular genetic analyses of these cichlid species suggest that an radiation -- driven in part by interspecies hybridization - was already underway in the rivers and lakes that drained into the Proto-Lake Tanganyika. "In fish, it is not uncommon for such hybrids, which display characters derived from both parental species, to be fertile and capable of producing fertile progeny," says Schliewen. During the Miocene and Pliocene periods, the climate of East Africa became more arid, and many feeder streams dried up. As a result, many cichlid species that had originated in riverine systems were isolated in Lake Tanganyika basin itself, which thus became a 'melting pot' for subsequent episodes of speciation to which these immigrant species contributed. "Our fossil supports the hypothesis that hybridizations played a more prominent role in cichlid speciation than was once thought - and that diversification of the cichlids now endemic to the lake did not begin in the lake itself," Reichenbacher says. The new fossil also elucidates aspects of the environment in which Lake Tanganyika formed. It was discovered by Reichenbacher and her coworkers in Kenya's Tugen Hills, in the eastern arm of the East African Rift Valley, but Lake Tanganyika -- in which its closest relatives now live -- is located in the Valley's western branch. The fossil therefore provides further evidence for a previously postulated hydrological connection between the eastern and western arms of the Rift Valley, which was subsequently severed as rifting progressed.
News Article | March 30, 2017
Paleontologists have revealed the discovery of the world's biggest dinosaur footprint as well as the world's most diverse collection of dinosaur tracks in Australia. The gigantic footprint belonged to a sauropod, an herbivorous dinosaur marked by its long neck, which likely measured 17 feet and 9 inches high at the hips. The track, which measures nearly 5 feet and 9 inches, is bigger than the previous record holder, which measured just nearly 3 feet and 9 inches. The footprint is just one of a series of finds that scientists discovered in Australia's "Jurassic Park." Researchers also found 21 different dinosaur tracks and some rocks dating back from as early as 140 million years ago. The footprints, which were between 140 million and 127 million years old, vary in size. They range from small, measuring about 8 inches, to very large, measuring over 5 feet in length. The footprints are considered as trace fossils, left behind by animals but are not parts of the animals themselves. The trace fossils revealed the diversity of dinosaurs that lived around the region during the Cretaceous period, the geologic period marked by relatively warm climate and an abundance of now-extinct marine reptiles, ammonites, and dinosaurs. The Cretaceous period ended with the Cretaceous-Paleogene extinction event, in which some three-quarters of animals and plants on the planet died out. Analyses showed five different track types of predatory dinosaurs, six track types of sauropods, four track types of herbivorous ornithopods, and six track types of armored dinosaurs. Paleontologist Steve Salisbury from the University of Queensland said that the findings show that Broome, a town on Australia's western coast, was once a dinosaur hot spot. He said that the diversity of the tracks was unparalleled on a global level and made the area the "Cretaceous equivalent of the Serengeti." Serengeti in Africa currently hosts the largest terrestrial mammal migration in the world. The region hosts about 70 large mammal and 500 bird species. "The overall diversity of the dinosaurian ichnofauna of the Broome Sandstone in the Yanijarri-Lurujarri section of the Dampier Peninsula is unparalleled in Australia, and even globally," the researchers wrote in their study, which was published on March 24 in the Journal of Vertebrate Paleontology. "[T]his ichnofauna provides our only detailed glimpse of Australia's dinosaurian fauna during the first half of the Early Cretaceous," they added. The tracks are not just fascinating. Scientists are also excited about the find since the dinosaur footprints can help them learn more about the anatomy, diversity, and evolution of the dinosaurs. Analyses of dinosaur bones allow scientists to study the iconic prehistoric animals, but footprints also offer an array of information about these large creatures. "What stands out are [the footprints'] immense physical size and the great variety of dinosaur tracks found there," said paleontologist Steve Brusatte from the University of Edinburgh. "Obviously, this part of Australia must have been a dinosaur stomping ground during the Early Cretaceous." © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | May 3, 2017
A 145-million-year-old dinosaur about the size of a wild turkey sported a plume of tail feathers that were surprisingly modern-looking and aerodynamic in shape, a new study finds. Though flight ready, the beast's tail feathers may or may not have been used for flying, said the researchers who found the exceptional specimen, a roughly 3.6-foot-long (1.1 meters) dinosaur, in 2015 in China's Liaoning Province, an area known for its incredibly well-preserved fossils of dinosaurs with feathers. The scientists named the find Jianianhualong tengi, after Jianianhua, the Chinese company that supported the study, and "long," the Mandarin word for "dragon," the researchers said. The species name honors Fangfang Teng, the director of the Xinghai Paleontological Museum of Dalian in China, who helped the paleontologists access the specimen. [Images: These Downy Dinosaurs Sported Feathers] J. tengi, which weighed just over 5 lbs. (2.4 kilograms), was a troodontid, a bird-like theropod. Though most theropods, such as Velociraptor and Tyrannosaurus rex, were carnivorous, J. tengi was likely an omnivore, based on its tooth anatomy and the diet of its closest relatives, said study co-lead researcher Michael Pittman, an assistant professor of vertebrate paleontology at the University of Hong Kong. Unlike the symmetrical feathers seen on most dinosaurs from the Cretaceous period, J. tengi's feathers were asymmetrical, with the vanes on one side of the central shaft longer than those on the other side — a feature that is crucial for flight, the researchers said. "Bird feathers need to be asymmetrical in order to form an airfoil," said Steve Brusatte, a vertebrate paleontologist at the University of Edinburgh, who was not involved with the study. "It has to do with the physics of wing shape, the same way that airplane wings have to be designed a certain way." However, asymmetrical feathers "are also found in species that do not fly," making it unclear whether the Cretaceous-age dinosaur could take flight, Pittman said. The asymmetrical feathers on J. tengi's tail are the first record of aerodynamically associated feathers in the bird-like troodontid dinosaurs, Pittman said. The Velociraptor relative Microraptor (a dromaeosaur) also had asymmetrical feathers, Pittman said. "This reveals that the closest common ancestor of birds (shared with troodontids and the bird-like dromaeosaur dinosaurs, raptors), possessed asymmetrical feathers," Pittman told Live Science in an email. The finding will likely help paleontologists decipher the timing of the evolution of asymmetrical feathers, both Pittman and Brusatte said. "Strangely enough, the asymmetrical feathers are on the tail," Brusatte told Live Science in an email. "Does this mean that Jianianhualong was using its tail to fly? It's hard to be sure." [Photos: Velociraptor Cousin Had Short Arms and Feathery Plumage] J. tengi's arm and leg feathers aren't preserved well enough to show their symmetry, "so we don't know what the feather condition of the entire animal would have been like," Brusatte said. "It is possible that Jianianhualong had asymmetrical tail feathers, but symmetrical (and thus non-flight-worthy) arm and leg feathers like most other nonbird dinosaurs. We just don't know." Perhaps feather asymmetry evolved first for display purposes before the features were used for flight, Brusatte said. The investigation into the history of flight is a hot topic, as a growing number of researchers try to determine which dinosaurs could fly. For instance, research presented at the 2016 Society of Vertebrate Paleontology meeting in Salt Lake City showed that several dinosaurs, such as Microraptor, and early birds, including Archaeopteryx, could likely fly for short distances, Live Science previously reported. The new study was published online today (May 2) in the journal Nature Communications.
News Article | April 14, 2017
In November 2010, ranch manager David Bradt was hunting elk in northeast Montana when he found what first appeared to be a petrified wood sticking out of a rock. He eventually discovered that it was a vertebrae of fossilized bones. That fossil helped researchers discover a new species of prehistoric marine reptile that swam in the inland sea flowing east of the Rocky Mountains about 70 million years ago. Scientists named the new species Nakonanectes bradti, which stands for Nakona, or Assiniboine, the people of northeastern Montana, and Bradt who first discovered the specimen while hunting elk. The marine animal belonged to a group of long-necked plesiosaurs called elasmosaur, which are characterized by small heads and paddle-like limbs and can grow up to 30 feet long. The carnivorous reptiles are a type of prehistoric marine creature that are known for their long neck that stretches 18 feet long. The fossil that Bradt discovered in the Charles M. Russell National Wildlife Refuge called MOR 3072 is distinct in that it belonged to a creature that has a shorter neck measuring just about 7.5 feet. Paleontologist Patrick Druckenmiller, from the University of Alaska Museum of the North, who coauthored the study describing the fossilized remains of the new species, said that this group of prehistoric animals is known for their long necks, which contain as many as 76 vertebrae. "What absolutely shocked us when we dug it out — it only had somewhere around 40 vertebrae," Druckenmiller said. The creature lived in the same area and at the same time as its larger relatives, which contradicts the idea that elasmosaurs did not evolve over a period spanning millions of years to have their longer necks. Fossils of these creatures have been found across the world, but the one that was discovered in Montana was nearly complete and was well-preserved. When Bradt found the fossils, he initially thought these belonged to a triceratops. He was surprised to learn it was a sea creature because he did not know there used to be an ocean there. Bradt took photos and reported his find to the Museum of the Rockies in Bozeman and the U.S. Fish and Wildlife Service. It took three days before the fossil was excavated. Millions of years ago, dinosaurs such as Tyrannosaurus rex, Thescelosaurus, Triceratops, and Pachycephalosaurus inhabited the land and sea in the area. Researchers said that the inland sea was also teeming with marine creatures, but relatively a few of these fossils have so far been excavated. "MOR 3072 is one of the smallest adult elasmosaurids ever recovered (5.1-5.6 m) and exhibits a reduced neck length compared with other North American elasmosaurids, resulting from a reduction in both centrum length and number of cervical vertebrae (39-42 were originally present)," researchers wrote in their study, which was published in the Journal of Vertebrate Paleontology on Thursday, April 13. "These features are convergent with the Southern Hemisphere clade of short-necked Maastrichtian elasmosaurids, Aristonectinae, and demonstrate multiple origins of short-necked body proportions from longer-necked ancestors within Elasmosauridae." © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | January 22, 2016
Around 85 million years ago, North America was halved by 1,000 mi of ocean, which connected the Gulf of Mexico to the Arctic Sea. The continent was divided into two landmasses: Laramidia and Appalachia. Appalachia stretched from around Alabama up into Canada. Traversing Appalachia was Eotrachodon orientalis, a new duck-billed dinosaur described by researchers in the Journal of Vertebrate Paleontology. Found in marine sediment by a team of amateur fossil hunters in Alabama’s Montgomery County, the skeleton is roughly 40 to 45% complete, consisting of a complete skull, backbones, a partial hip bone, and some bones from the dinosaur’s limbs. According to the researchers, the dinosaur most likely grew to between 20 and 30 ft, and had a scaly exterior. It walked on its hind legs, save for when it was grazing for plants. Based on its teeth, scientists believe the dinosaur ground its food up like cows or horses. But unlike other Hadrosaurids, this species had a unique feature. “This thing had a big ugly nose,” said Gregory Erickson, a professor of biological science at Florida State Univ. After the fossil hunters found the bones, a team from the McWane Science Center finished the excavation. A subsequent study was performed by science center staff, Erickson, and former Florida State Univ. doctoral student Albert Prieto-Marquez. Erickson determined the dinosaur’s adult length by studying the bone samples in his Florida State Univ. lab. Apparently no growth lines appeared in the samples. But highly vascularized bones proved the dinosaur was in a state of rapid growth when it perished. “For roughly 100 million years, the dinosaurs were not able to cross the barrier,” said Jun Ebersole, the McWane Science Center’s director. “The discovery of Eotrachodon suggests that duck-billed dinosaurs originated in Appalachia and dispersed to other parts of the world at some point after the seaway lowered, opening a land corridor to western North America.” The dinosaur’s name means “dawn rough tooth from the east.” “This is a really important animal in telling us how they came to be and how they spread all over the world,” said Erickson.
News Article | November 8, 2016
Today's turtles don't have teeth; they cut off their food using hard ridges on their jaws. But their ancestors were not so dentally challenged. A team of international researchers including Dr. Márton Rabi from the Biogeology Lab of the University of Tübingen has now discovered that turtles with remnants of teeth survived 30 million years later than previously thought. The researchers found evidence of this at a major excavation site in China's western Autonomous Region of Xinjiang. Up to now, the most recent finds of toothed turtles were 190 million years old. The new discovery also helps to fill in some of the puzzle pieces in the chelonian family tree and in the distribution of the family over many millions of years. The researchers have published their findings in the latest edition of BMC Evolutionary Biology. The Xinjiang site of Wucaiwan is well known for the remarkable Middle to Late Jurassic dinosaur fossils found there. But among the extinct giants are the fossils of many other animals which shed light on the long evolutionary history of tortoises and turtles, of which more than 350 different species live around the world today. A team headed by study co-author Dr. Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing identified a previously unknown extinct chelonian species, naming it Sichuanchelys palatodentata -- the turtle with a toothed palate. "Scientists had previously known that the earliest turtles still had teeth in their palates, a primitive feature they inherited from their reptilian ancestors," says lead author Dr. Walter Joyce from the University of Fribourg, Switzerland. "Previously, the last toothed turtle, however, was known from 30 million years older rocks. It is therefore a great surprise to find a toothed turtle that survived even longer." The researchers were able to classify the new turtle among the known families of chelonians -- as well as learning more about the biogeographic history of turtles. "Our analysis revealed that the new turtle is the closest known relative of a large terrestrial turtle, Mongolochelys efremovi, that lived almost 100 million years later in central Asia," says Dr. Rabi. "It seemed a bizarre turtle that previously had no known close relatives, but now we see that it represents the final links of a long lineage that persisted throughout Asia for much of the Mesozoic." "Although living turtles are not particularly mobile, people had not previously recognized significant links between the distribution of fossil and recent turtles and the configuration of the continents, as they did for frogs or other amphibians," says Dr. Clark, a coauthor from George Washington University, USA. "Our analysis reveals that the initial diversification of turtles was controlled by the breakup of the super continent Pangea during the Jurassic to Cretaceous," says Dr. Joyce. "Each continent thereby developed its own unique turtle fauna, like the extinct turtle lineage we newly discovered from Asia."
News Article | December 22, 2016
WASHINGTON (Dec. 22, 2016)--Researchers have discovered that a species of dinosaur, Limusaurus inextricabilis, lost its teeth in adolescence and did not grow another set as adults. The finding, published today in Current Biology, is a radical change in anatomy during a lifespan and may help to explain why birds have beaks but no teeth. The research team studied 19 Limusaurus skeletons, discovered in "death traps," where they became mired in mud, got stuck and died, in the Xinjiang Province of China. The dinosaurs ranged in age from baby to adult, showing the pattern of tooth loss over time. The baby skeleton had small, sharp teeth, and the adult skeletons were consistently toothless. "This discovery is important for two reasons," said James Clark, a co-author on the paper and the Ronald Weintraub Professor of Biology at the George Washington University's Columbian College of Arts and Sciences. "First, it's very rare to find a growth series from baby to adult dinosaurs. Second, this unusually dramatic change in anatomy suggests there was a big shift in Limusaurus' diet from adolescence to adulthood." Limusaurus is part of the theropod group of dinosaurs, the evolutionary ancestors of birds. Dr. Clark's team's earlier research of Limusaurus described the species' hand development and notes that the dinosaur's reduced first finger may have been transitional and that later theropods lost the first and fifth fingers. Similarly, bird hands consist of the equivalent of a human's second, third and fourth fingers. These fossils indicate that baby Limusaurus could have been carnivores or omnivores while the adults were herbivores, as they would have needed teeth to chew meat but not plants. Chemical makeup in the fossils' bones supports the theory of a change in diet between babies and adults. The fossils also could help to show how theropods such as birds lost their teeth, initially through changes during their development from babies to adults. "For most dinosaur species we have few specimens and a very incomplete understanding of their developmental biology," said Josef Stiegler, a graduate student at George Washington University and co-author. "The large sample size of Limusaurus allowed us to use several lines of evidence including the morphology, microstructure and stable isotopic composition of the fossil bones to understand developmental and dietary changes in this animal." The research was performed by Shuo Wang of the Capital Normal University and graduate student Josef Stiegler of George Washington University under the guidance of Dr. Xu Xing of the Institute of Vertebrate Paleontology and Paleoanthropology and Dr. Clark, and funded by National Science Foundation grant EAR 0922187.
News Article | October 28, 2016
SALT LAKE CITY — About 120 million years ago, a bird dunked its beak into the water, caught a fish and, after digesting the meal, coughed up a pellet full of fish bones. The bird died moments later, but now its fossils are the oldest evidence of a bird pellet on record, a new study reported. The pellet — the first that is unambiguously from a bird that lived during the Mesozoic, the age of the dinosaurs — indicates that the ancient bird had a two-chambered stomach, much like birds do today, the researchers said. Modern-day birds, including many birds of prey, produce pellets made up of indigestible material, such as bones, hair and feathers. [Avian Ancestors: Dinosaurs That Learned to Fly (Gallery)] "The very presence of the gastric pellet in the new specimen indicates that some key features of the modern birds' digestive systemhad already appeared in these early Cretaceous birds over 120 million years [ago]," said the study's lead author, Min Wang, an associate professor at the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences. (The Cretaceous Period was the last part of the Mesozoic Era and spanned from 145 million years ago to about 66 million years ago.) The stunning specimen was found in 2014 in the Jiufotang Formation, located in northeastern China's Liaoning Province. After examining the animal's anatomy, Wang and his colleagues determined that the bird belonged to the enantiornithes, the most diverse group of Mesozoic birds, Wang said. Despite the number of enantiornithes fossils that researchers have uncovered over the past three decades, "only this new specimen provides the direct evidence that some enantiornithine birds were piscivorous (ate fish)," Wang wrote. He noted that another enantiornithine bird dating to the Cretaceous period in modern-day Spain has crustacean exoskeletons in its digestive tract, providing more evidence that some of these ancient birds dined on marine animals."Their fossilized materials have been discovered from every continent except the Antarctic," Wang told Live Science in an email. An array of modern animals cough up pellets; this includes many raptors and seabirds, as well as crocodilians, squamates (scaled reptiles) and some marine mammals, Wang said. These animals still pass waste, but their pellets contain other indigestible food items, he said. "The digestive system of living birds are characterized by a two chambered-stomach with a muscular gizzard capable of compacting indigestible matter into a cohesive pellet, and efficient antiperistalsis," the process of "coughing up" the pellet, Wang said. "Our discovery suggests that all these features are present in some early Cretaceous birds … [and] thus key features of modern birds' digestive system occurred earlier than we thought." The study was published in May in the journal Current Biology, and was presented Wednesday (Oct. 26) at the 76th annual meeting of the Society of Vertebrate Paleontology.
News Article | March 1, 2017
Since their discovery in 2010, the extinct ice age humans called Denisovans have been known only from bits of DNA, taken from a sliver of bone in the Denisova Cave in Siberia, Russia. Now, two partial skulls from eastern China are emerging as prime candidates for showing what these shadowy people may have looked like. In a paper published this week in , a Chinese-U.S. team presents 105,000- to 125,000-year-old fossils they call “archaic Homo.” They note that the bones could be a new type of human or an eastern variant of Neandertals. But although the team avoids the word, “everyone else would wonder whether these might be Denisovans,” which are close cousins to Neandertals, says paleoanthropologist Chris Stringer of the Natural History Museum in London. The new skulls “definitely” fit what you’d expect from a Denisovan, adds paleoanthropologist María Martinón-Torres of the University College London—“something with an Asian flavor but closely related to Neandertals.” But because the investigators have not extracted DNA from the skulls, “the possibility remains a speculation.” Back in December 2007, archaeologist Zhan-Yang Li of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing was wrapping up his field season in the town of Lingjing, near the city of Xuchang in the Henan province in China (about 4000 kilometers from the Denisova Cave), when he spotted some beautiful quartz stone tools eroding out of the sediments. He extended the field season for two more days to extract them. On the very last morning, his team discovered a yellow piece of rounded skull cap protruding from the muddy floor of the pit, in the same layer where he had found the tools. The team went back for another six seasons and managed to find 45 more fossils that fit together into two partial crania. The skulls lack faces and jaws. But they include enough undistorted pieces for the team to note a close resemblance to Neandertals. One cranium has a huge brain volume of 1800 cubic centimeters—on the upper end for both Neandertals and moderns—plus a Neandertal-like hollow in a bone on the back of its skull. Both crania have prominent brow ridges and inner ear bones that resemble those of Neandertals but are distinct from our own species, Homo sapiens. However, the crania also differ from the western Neandertals of Europe and the Middle East. They have thinner brow ridges and less robust skull bones, similar to early modern humans and some other Asian fossils. “They are not Neandertals in the full sense,” says co-author Erik Trinkaus, a paleoanthropologist at Washington University in St. Louis in Missouri. Nor are the new fossils late-occurring representatives of other archaic humans such as H. erectus or H. heidelbergensis, two species that were ancestral to Neandertals and modern humans. The skulls are too lightly built and their brains are too big, according to the paper. The skulls do share traits with some other fossils in east Asia dating from 600,000 to 100,000 years ago that also defy easy classification, says paleoanthropologist Rick Potts of the Smithsonian National Museum of Natural History in Washington, D.C. Those features include a broad cranial base where the skull sits atop the spinal column and a low, flat plateau along the top of the skull. The Lingjing crania also resemble another archaic early human skull that dates to 100,000 years ago from Xujiayao in China’s Nihewan Basin 850 kilometers to the north, according to co-author Xiu-Jie Wu, a paleoanthropologist at IVPP. Wu thinks those fossils and the new skulls “are a kind of unknown or new archaic human that survived on in East Asia to 100,000 years ago.” Based on similarities to some other Asian fossils, she and her colleagues think the new crania represent regional members of a population in eastern Asia who passed local traits down through the generations in what the researchers call regional continuity. At the same time, resemblances to both Neandertals and modern humans suggest that these archaic Asians mixed at least at low levels with other archaic people. To other experts, the Denisovans fit that description: They are roughly dated to approximately 100,000 to 50,000 years ago, and their DNA shows that after hundreds of thousands of years of isolation, they mixed both with Neandertals and early modern humans. “This is exactly what the DNA tells us when one tries to make sense of the Denisova discoveries,” says paleoanthropologist Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “These Chinese fossils are in the right place at the right time, with the right features.” But Wu and Trinkaus say they can’t put fossils in a group defined only by DNA. “I have no idea what a Denisovan is,” Trinkaus says. “Neither does anybody else. It’s a DNA sequence.” The only way to truly identify a Denisovan is with DNA. IVPP paleogeneticist Qiaomei Fu says she tried to extract DNA from three pieces of the Xuchang fossils but without success. Regardless of the new skulls’ precise identity, “China is rewriting the story of human evolution,” Martinón-Torres says. “I find this tremendously exciting!”
News Article | April 23, 2016
A giant, fossilized tooth of an ancient killer whale was discovered in Beaumaris Bay. The huge tooth measuring 30 centimeters (12 inches) long, estimated to be about 5 million years old from the Pliocene epoch, is a proof that killer sperm whales once inhabited Australian seas. Murray Orr, a fossil enthusiast was walking along the beach of Beaumaris Bay - a known fossil site, when he stumbled upon the giant tooth. "After I found the tooth I just sat down and stared at it in disbelief," said Orr. "I knew this was an important find that needed to be shared with everyone." Dr. Erich Fitzgerald, Senior Curator of Vertebrate Paleontology at Museum Victoria said the fossil would be used for scientific research and education. "If we only had today's sperm whales to go on, we could not predict that just five million years ago, there were giant predatory sperm whales with immense teeth that hunted other whales," said Fitzgerald. Fitzgerald said that the dental dimensions were bigger than that of a Tyrannosaurus rex. He also noted that the tooth looks incomplete - the tip of the crown and some base of the root are missing and could be from a whale which was not fully grown yet. Fitzgerald is intrigued as to how only one of the species of the whales continues to survive today. Through the fossil, he wants to know how the whales co-existed in the past, how the oceans supported them, and why they were lost. The fossil belonged to an extinct sperm whale species, which is believed to be related to Livyatan melvillei that lived during the Serravallian stage of the Miocene epoch, about 12 to 13 million years ago. Fitzgerald said the finding is valuable in preserving Australia's fossil heritage. Just recently Australian scientists completed years of fossil analysis, which revealed a new dinosaur species - Kunbarrasaurus. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.