100-Million-Year-Old Coelacanth Fish Discovered in Texas Is New Species from Cretaceous.

Source: ScienceDaily

-------------------------------

ScienceDaily (Oct. 24, 2012) — A new species of coelacanth fish has been discovered in Texas. The species is now the youngest coelacanth from Texas; fish jaw and cranial material indicate a new family -- Dipluridae -- that was evolutionary transition between two previously known families.
Pieces of tiny fossil skull found in Fort Worth have been identified as 100 million-year-old coelacanth bones, according to paleontologist John F. Graf, Southern Methodist University, Dallas.
The coelacanth has one of the longest lineages -- 400 million years -- of any animal. It is the fish most closely related to vertebrates, including humans.
The SMU specimen is the first coelacanth in Texas from the Cretaceous, said Graf, who identified the fossil. The Cretaceous geologic period extended from 146 million years ago to 66 million years ago.
Graf named the new coelacanth species Reidus hilli.
Coelacanths have been found on nearly every continent
Reidus hilli is now the youngest coelacanth identified in the Lone Star State.
Previously the youngest was a 200 million-year-old coelacanth from the Triassic. Reidus hilli is the first coelacanth ever identified from the Dallas-Fort Worth area.
Coelacanth fossils have been found on every continent except Antarctica. Few have been found in Texas, Graf said.
The coelacanth fish has eluded extinction for 400 million years. Scientists estimate the coelacanth reached its maximum diversity during the Triassic.
The coelacanth was thought to have gone extinct about 70 million years ago. That changed, however, when the fish rose to fame in 1938 after live specimens were caught off the coast of Africa. Today coelacanths can be found swimming in the depths of the Indian Ocean.
Chart courtesy of the British Geological Survey.
Closest living fish to all vertebrates alive on land "
These animals have one of the longest lineages of any vertebrates that we know," Graf said.
The SMU specimen demonstrates there was greater diversity among coelacanths during the Cretaceous than previously known.
"What makes the coelacanth interesting is that they are literally the closest living fish to all the vertebrates that are living on land," he said. "They share the most recent common ancestor with all of terrestrial vertebrates."
Coelacanths have boney support in their fins, which is the predecessor to true limbs.
"Boney support in the fins allows a marine vertebrate to lift itself upright off the sea floor," Graf said, "which would eventually lead to animals being able to come up on land."
Texas coelacanth, Reidus hilli, represents a new species and a new family
Graf identified Reidus hilli from a partial skull, including gular plates, which are bones that line the underside of the jaw.
"Coelacanths are not the only fish that have gular plates, but they are one of the few that do," Graf said. "In fact, the lenticular shape of these gular plates is unique to coelacanths. That was the first indicator that we had a fossil coelacanth."
Reidus hilli was an adult fish of average size for the time in which it lived, said Graf. While modern coelacanths can grow as large as 3 meters, Reidus hilli was probably no longer than 40 centimeters. Its tiny skull is 45 millimeters long by 26 millimeters wide, or about 1.75 inches long by 1 inch wide.
Reidus hilli's total body size is typical of the new family of coelacanths, Dipluridae, which Graf describes and names. He chose the name for the least primitive coelacanth in the family, Diplurus, which lived during the Triassic.
"Reidus hilli helped me tie a group of coelacanths together into what I identify as a new family of coelacanths," he said. "This family represents a transition between the two large groups of youngest living coelacanths from the fossil record, Mawsoniidae and Latimeriidae."
Diplurid coelacanths are typically smaller than the two families with which they are most closely associated, Mawsoniidae and Latimeriidae. Mawsoniidae and Latimeriidae both have late Cretaceous members reaching large body sizes, ranging from 1 meter to 3 meters in total body length, Graf said.
Reidus hilli provides clues to missing coelacanth history Reidus hilli is named, in part, for the amateur collector who discovered the fish, Robert R. Reid.
A Fort Worth resident, Reid has collected fossils for decades. He found the fossil specimen while walking some land that had been prepared for construction of new homes. Reid noticed the fossil lying loose on the ground in a washed out gully created by run-off.
Following Graf's analysis, Reid was surprised to learn he'd collected a coelacanth -- and a new species.
"When I found it, I could tell it was a bone but I didn't think it was anything special," said Reid, recalling the discovery. "I certainly didn't think it was a coelacanth."
At the time, SMU paleontologist Louis L. Jacobs recommended to Reid that he donate the fossil and have it scientifically identified. Reid gave the fossil to SMU's Shuler Museum of Paleontology in the Roy M. Huffington Department of Earth Sciences.
"It is astounding what can be learned from the discoveries that people like Rob Reid make in their own backyards," said Jacobs, an SMU professor of earth sciences and president of SMU's Institute for the Study of Earth and Man. "The discovery of living coelacanths in the Indian Ocean after being presumed extinct for 70 million years highlights one of the great mysteries of ocean life. Where were they all that time? The new fossil from Texas is a step toward understanding this fascinating history."
Reidus hilli is the latest of many fossils Reid has discovered. Others also have been named for him.
Reidus hilli discovered in Duck Creek Formation of North Texas
Reidus hilli came from the fossil-rich Duck Creek Formation, which is a layer-cake band of limestone and shale about 40 feet thick.
The fossil was found in marine sediments, Graf said. It is one of many marine fossils found in the North Texas area, which 100 million years ago was covered by the Western Interior Seaway that divided North America from the Gulf of Mexico to the Arctic Ocean.
"That is unique to younger coelacanths," Graf said. "The oldest coelacanths were usually found in freshwater deposits and it wasn't until the Cretaceous that we start seeing this transition into a more marine environment."
Fossil also named for Robert T. Hill, "Father of Texas Geology"
Graf also named the fossil for Robert T. Hill, a geologist with the U.S. Geological Survey who led surveys of Texas during the 1800s. Hill described much of the geology of Texas, including the Duck Creek Formation. Hill is acclaimed as the "Father of Texas Geology."
Identification of Reidus hilli brings the number of coelacanth species worldwide to 81, including two that are alive today. Sources report that 229 living coelacanths have been caught since 1938.

Story Source:

The above story is reprinted from materials provided by Southern Methodist University. The original article was written by Margaret Allen.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

---

Journal Reference:

1. John Graf. A new Early Cretaceous coelacanth from Texas. Historical Biology: An International Journal of Paleobiology, Volume 24, Issue 4, 2012 DOI: 10.1080/08912963.2012.696636

Chinese scientist says prehistoric man ate pandas.

Source: Phys.org

-------------------------

China's beloved national symbol—the panda—may have been seen quite differently by ancient humans: as food.
Scientist Wei Guangbiao says prehistoric man ate pandas in an area that is now part of the city of Chongqing in southwest China. Wei, head of the Institute of Three Gorges Paleoanthropology at a Chongqing museum, says many excavated panda fossils "showed that pandas were once slashed to death by man." The Chongqing Morning Post quoted him Friday as saying: "In primitive times, people wouldn't kill animals that were useless to them" and therefore the pandas must have been used as food. But he says pandas were much smaller then. Wei says wild pandas lived in Chongqing's high mountains 10,000 to 1 million years ago. The Chinese government invests greatly in studying the native species and trying to ensure its survival. Pandas number about 1,600 in the wild, where they are critically endangered due to poaching and development. More than 300 live in captivity, mostly in China's breeding programs.

New Fossil Penguin from New Zealand May Be the Biggest Ever.

Two Kairuku penguins come ashore, passing a stranded Waipatia dolphin. (Credit: Artwork by Chris Gaskin, owner and copyright owner: Geology Museum, University of Otago. Used with permission.)

Source: Science Daily

--------------------------------

ScienceDaily (Feb. 27, 2012) — After 35 years, a giant fossil penguin has finally been completely reconstructed, giving researchers new insights into prehistoric penguin diversity.

The bones were collected in 1977 by Dr. Ewan Fordyce, a paleontologist from the University of Otago, New Zealand. In 2009 and 2011, Dr. Dan Ksepka, North Carolina State University research assistant professor of marine, earth and atmospheric sciences and North Carolina Museum of Natural Sciences colleague Dr. Paul Brinkman traveled to New Zealand to aid in the reconstruction of the giant penguin fossil.
Researchers dubbed the penguin Kairuku, a Maori word that loosely translates to "diver who returns with food." Ksepka was interested in the fossil because its body shape is different from any previously known penguin, living or extinct. He was also interested in the diversity of penguin species that lived in what is now New Zealand during the Oligocene period, approximately 25 million years ago.
According to Ksepka, "The location was great for penguins in terms of both food and safety. Most of New Zealand was underwater at that time, leaving isolated, rocky land masses that kept the penguins safe from potential predators and provided them with a plentiful food supply."
Kairuku was one of at least five different species of penguin that lived in New Zealand during the same period. The diversity of species is part of what made the reconstruction difficult, and the penguin's unique physique added to the difficulty.
"Kairuku was an elegant bird by penguin standards, with a slender body and long flippers, but short, thick legs and feet," says Ksepka. "If we had done a reconstruction by extrapolating from the length of its flippers, it would have stood over 6 feet tall. In reality, Kairuku was around 4-feet-2 inches tall or so."
The researchers reconstructed Kairuku from two separate fossils, using the skeleton of an existing king penguin as a model. The result is a tall bird with an elongated beak and long flippers -- easily the largest of the five species that were common to the area in that time period.
New Zealand has a history of producing exceptional fossils that give important insights into the history of penguins and other marine creatures. Ksepka hopes that the reconstruction of Kairuku will give other paleontologists more information about some the other fossils found in that area as well as add to the knowledge about giant penguin species. "This species gives us a more complete picture of these giant penguins generally, and may help us to determine how great their range was during the Oligocene period."
Ksepka's research was funded by a grant from the National Science Foundation and support from the University of Otago. Ksepka has a research appointment at the North Carolina Museum of Natural Sciences. The Department of Marine, Earth and Atmospheric Sciences is part of the College of Physical and Mathematical Sciences.

Missing 500-Years of Loggias, Porticos Described.

Porticos are roof-covered structures supported by columns. (Credit: iStockphoto/Nils Kahle)

Source: ScienceDaily

--------------------------

ScienceDaily (Jan. 14, 2010) — Using texts and images, a University of Arkansas researcher has for the first time reconstructed the time when the use of porticos -- roof-covered structures supported by columns -- gave way to loggias, or recessed porticos.

In an article in the Journal of the Society of Architectural Historians, architecture professor Kim Sexton accounts for the time between the 7th and 12th centuries when there are no surviving porticos. In European history, loggias represented more than just interesting architectural features. They also served important cultural functions.
"It's important because we had porticos in Roman times, and then they come back in the Renaissance," she said. "It's unaccounted time -- what happened in between?"
Sexton argues that they returned to prominence because different ethnic groups used them "to display their judicial systems." As court proceedings were held outdoors, "they used different styles to frame that." At times there was German law and at other times, Roman law, and certain loggia announced each style.
"In this competitive kind of culture, they start to use the portico again," Sexton said. "From there it comes back into prominence in the Renaissance and late medieval Italy."
Loggias were "used to display activities that were kind of new, and maybe people felt unsure about their value. So that they wanted to display there was something good about the justice system." She compares it to television today, as a powerful medium that can influence behavior.
Loggias and porticos have long interested Sexton. "They seem at once so transparent in their function because they seem like simple shelters," she said. "But then, why did they come to be built with such magnificent architecture by some of the best architects of the Renaissance?"
Sexton discovered images in several medieval sources -- the center of a gem, illustrations of the book of Psalms, illuminations from law codes and encyclopedias. The article's most important image, which is in color on the journal's cover, shows the only known instance of a king in a loggia where a trial is actually in progress.
"If you see them empty, you're not getting what it's about," she said of loggias. "You have to see it when they're full of activity."
Sexton is associate professor of architecture, Fay Jones School of Architecture, University of Arkansas.

Story Source:
Adapted from materials provided by University of Arkansas, Fayetteville, via Newswise.

Shipworm Threatens Archaeological Treasures.

The shipworm, Teredo navalis, infesting a pier pole in the Swedish province of Bohuslän.

Source: ScienceDaily

----------------------------

ScienceDaily (Jan. 13, 2010) — The dreaded shipworm is moving into the Baltic Sea, threatening artefacts of the area's cultural heritage. Researchers at the University of Gothenburg, Sweden, suspect that the unfortunate spread is due to climate change, and are currently involved in an EU project to determine which archaeological remains are at risk.

The shipworm is capable of completely destroying large maritime archaeological finds in only 10 years, and while it has avoided the Baltic Sea in the past, since it does not do well in low salinity water, it can now be spotted along both the Danish and German Baltic Sea coasts.

Malmö landmark infested:
'The shipworm has for example attacked shipwrecks from the 1300s off the coast of Germany, and we are also starting to see its presence along the Swedish coast, for example at the Ribersborg cold bath house in Malmö,' says Christin Appelqvist, doctoral student at the Department of Marine Ecology, University of Gothenburg.

Effect of climate change:
Appelqvist and her colleagues believe that the development may be due to climate change. In short, the increased water temperature may help the shipworms to become adapted to lower salinity. The group is part of the EU project WreckProtect, a cooperative effort to assess which archaeological treasures are at risk. The project includes researchers from Sweden, Denmark and the Netherlands, as well as experts from France and Germany.

Covering the shipwrecks:
One of the objectives is to develop methods to protect the shipwrecks, for example by covering them with geotextile and bottom sediment, and another is to try to predict to which areas the shipworm is likely to spread in the future. The researchers say there are some 100 000 well-preserved shipwrecks in the Baltic Sea.
'Around 100 wrecks are already infested in the Southern Baltic, but yet it hasn't even spread past Falsterbo. We know it can survive the salinity of the Stockholm archipelago, although it needs water with higher salinity than that to be able to reproduce,' says Appelqvist.

Story Source:
Adapted from materials provided by University of Gothenburg.

Use of Body Ornamentation Shows Neanderthal Mind Capable of Advanced Thought.

Source: ScienceDaily

--------------------------

ScienceDaily (Jan. 11, 2010) — The widespread view of Neanderthals as cognitively inferior to early modern humans is challenged by new research from the University of Bristol published in Proceedings of the National Academy of Sciences.

Professor João Zilhão and colleagues examined pigment-stained and perforated marine shells, most certainly used as neck pendants, from two Neanderthal-associated sites in the Murcia province of south-east Spain (Cueva de los Aviones and Cueva Antón). The analysis of lumps of red and yellow pigments found alongside suggest they were used in cosmetics. The practice of body ornamentation is widely accepted by archaeologists as conclusive evidence for modern behaviour and symbolic thinking among early modern humans but has not been recognised in Neanderthals -- until now.
Professor Zilhão said: "This is the first secure evidence that, some 50,000 years ago -- ten millennia before modern humans are first recorded in Europe -- the behaviour of Neanderthals was symbolically organised."
A Spondylus gaederopus shell from the same site contained residues of a reddish pigmentatious mass made of lepidocrocite mixed with ground bits of hematite and pyrite (which, when fresh, have a brilliant black, reflective appearance), suggesting the kind of inclusion 'for effect' that one would expect in a cosmetic preparation.
The choice of a Spondylus shell as the container for such a complex recipe may relate to the attention-grabbing crimson, red, or violet colour and exuberant sculpture of these shells, which have led to their symbolic- or ritual-related collection in a variety of archaeological contexts worldwide.
A concentration of lumps of yellow colorant from Cueva de los Aviones (most certainly the contents of a purse made of skin or other perishable material) was found to be pure natrojarosite -- an iron mineral used as a cosmetic in Ancient Egypt.
While functionally similar material has been found at Neanderthal-associated sites before, it has been explained by stratigraphic mixing (which can lead to confusion about the dating of particular artefacts), Neanderthal scavenging of abandoned modern human sites, or Neanderthal imitation without understanding of behaviours observed among contemporary modern human groups.
For example, controversy has surrounded the perforated and grooved teeth and decorated bone awls found in the Châtelperronian culture of France. In earlier work, Professor Zilhão and colleagues have argued they are genuine Neanderthal artefacts which demonstrate the independent evolution of advanced cognition in the Neanderthal lineage.
However, the Châtelperronian evidence dates from 40,000 to 45,000 years ago, thus overlapping with the period when anatomically modern human people began to disperse into Europe (between 40,000 and 42,000 years ago) and leaving open the possibility that these symbolic artifacts relate, in fact, to them.
Professor Zilhão said: "The evidence from the Murcian sites removes the last clouds of uncertainty concerning the modernity of the behaviour and cognition of the last Neanderthals and, by implication, shows that there is no reason any more to continue to question the Neanderthal authorship of the symbolic artefacts of the Châtelperronian culture.
"When considering the nature of the cultural and genetic exchanges that occurred between Neanderthals and modern humans at the time of contact in Europe, we should recognise that identical levels of cultural achievement had been reached by both sides."
Accurate radiocarbon dating of shell and charcoal samples from Cueva de los Aviones and Cueva Antón was crucial to the research. The dating was undertaken at the University of Oxford's Radiocarbon Accelerator Unit.
Dr Thomas Higham, Deputy Director of the Radiocarbon Unit in the School of Archaeology said: "Dating samples that approach the limit of the technique, at around 55,000 years before present, is a huge challenge. We used the most refined methods of pre-treatment chemistry to obtain accurate dates for the sites involved by removing small amounts of more modern carbon contamination to discover that the shells and charcoal samples were as early as 50,000 years ago."

Story Source:
Adapted from materials provided by University of Bristol.

Journal Reference:
1.João Zilhão, Diego E. Angelucci Ernestina Badal-García, Francesco d%u2019Errico, Floréal Daniel, Laure Dayet, Katerina Douka, Thomas F. G. Higham, María José Martínez-Sánchez, Ricardo Montes-Bernárdez, Sonia Murcia-Mascarós, Carmen Pérez-Sirvent, Clodoaldo Roldán-García, Marian Vanhaeren, Valentín Villaverde, Rachel Wood, and Josefina Zapata. Symbolic use of marine shells and mineral pigments by Iberian Neandertals. Proceedings of the National Academy of Sciences, Online Jan. 11, 2010

Statistics Page

map counter



blog counter


flag counter

Fossil Footprints Give Land Vertebrates a Much Longer History.

Source: ScienceDaily

----------------------------

ScienceDaily (Jan. 8, 2010) — The discovery of fossil footprints from early backboned land animals in Poland leads to the sensational conclusion that our ancestors left the water at least 18 million years earlier than previously thought.

The results of the Polish-Swedish collaboration are published online in the journal Nature.
"These results force us to reconsider our whole picture of the transition from fish to land animals," says Per Ahlberg of Uppsala University, one of the two leaders of the study.
For nearly eighty years, palaeontologists have been scouring the planet for fossil bones and skeletons of the earliest land vertebrates or "tetrapods" -- the ultimate progenitors of all later amphibians, reptiles, birds and mammals including ourselves. Their discoveries have suggested that the first tetrapods evolved relatively rapidly from lobe-finned fishes, through a short-lived intermediate stage represented by "elpistostegids" such as Tiktaalik, about 380 million years ago. But there is another potential source of information about the earliest tetrapods: the fossilized footprints they left behind.
In the new study a Polish-Swedish team describe a rich and securely dated footprint locality from Zachelmie Quarry in Poland that pushes back the origin of tetrapods a full 18 million years beyond the earliest skeletal evidence and forces a dramatic reassessment of the transition from water to land.
The trackways show that large tetrapods, up to three metres in length, inhabited the marine intertidal zone during the early Middle Devonian some 395 million years ago.
"This means not that not only tetrapods but also elpistostegids originated much earlier than we thought, because the position of elpistostegids as evolutionary precursors of tetrapods is not in doubt, and so they must have existed at least as long," says Per Ahlberg.
The elpistostegids, it seems, were not at all a short-lived transitional stage but must have existed alongside their descendants the tetrapods for at least 10 million years. The environment is also a major surprise: almost all previous scenarios for the origin of tetrapods have placed this event in a freshwater setting and have associated it with the development of land vegetation and a terrestrial ecosystem.
"Instead, our distant ancestors may first have left the water in order to feed on stranded marine life left behind by the receding tide," says Per Ahlberg.

Story Source:
Adapted from materials provided by Uppsala University.

Journal Reference:
1.Grzegorz Niedźwiedzki, Piotr Szrek, Katarzyna Narkiewicz, Marek Narkiewicz & Per E. Ahlberg. Tetrapod trackways from the early Middle Devonian period of Poland. Nature, 2010; 463 (7277): 43 DOI: 10.1038/nature08623

30,000-Year-Old Child's Teeth Shed New Light on Human Evolution.

Source: ScienceDaily

------------------------

ScienceDaily (Jan. 8, 2010) — The teeth of a 30,000-year-old child are shedding new light on the evolution of modern humans, thanks to research from the University of Bristol published in the Proceedings of the National Academy of Sciences.

The teeth are part of the remarkably complete remains of a child found in the Abrigo do Lagar Velho, Portugal and excavated in 1998-9 under the leadership of Professor João Zilhão of the University of Bristol. Classified as a modern human with Neanderthal ancestry, the child raises controversial questions about how extensively Neanderthals and modern human groups of African descent interbred when they came into contact in Europe.
'Early modern humans', whose anatomy is basically similar to that of the human race today, emerged over 50,000 years ago and it has long been the common perception that little has changed in human biology since then.
When considering the biology of late archaic humans such as the Neanderthals, it is thus common to compare them with living humans and largely ignore the biology of the early modern humans who were close in time to the Neanderthals.
With this in mind, an international team, including Professor Zilhão, reanalysed the dentition of the Lagar Velho child (all of its deciduous -- milk -- teeth and almost all of its permanent teeth) to see how they compared to the teeth of Neanderthals, later Pleistocene (12,000-year-old) humans and modern humans.
Employing a technique called micro-tomography which uses x-rays to create cross-sections of 3D-objects, the researchers investigated the relative stages of formation of the developing teeth and the proportions of crown enamel, dentin and pulp in the teeth.
They found that, for a given stage of development of the cheek teeth, the front teeth were relatively delayed in their degree of formation. Moreover, the front teeth had a greater volume of dentin and pulp but proportionally less enamel than the teeth of recent humans.
The teeth of the Lagar Velho child thus fit the pattern evident in the preceding Neanderthals, and contrast with the teeth of later Pleistocene (12,000-year-old) humans and living modern humans.
Professor Zilhão said: "This new analysis of the Lagar Velho child joins a growing body of information from other early modern human fossils found across Europe (in Mladeč in the Czech Republic, Peştera cu Oase and Peştera Muierii in Romania, and Les Rois in France) that shows these 'early modern humans' were 'modern' without being 'fully modern'. Human anatomical evolution continued after they lived 30,000 to 40,000 years ago."
The team was led by Priscilla Bayle (Muséum National d'Histoire Naturelle, France) and Roberto Macchiarelli (Université de Poitiers, France) and included Erik Trinkaus (Professor of Anthropology at Washington University, St.-Louis, Cidália Duarte (Câmara Municipal do Porto, Portugal), and Arnaud Mazurier (CRI-Biopôle-Poitiers, France).

Story Source:
Adapted from materials provided by University of Bristol.

Journal Reference:
Priscilla Bayle, Roberto Macchiarelli, Erik Trinkaus, Cidália Duarte, Arnaud Mazurier, and João Zilhão. Dental maturational sequence and dental tissue proportions in the early Upper Paleolithic child from Abrigo do Lagar Velho, Portugal. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.0914202107

Ancient Rainforests Resilient To Climate Change.

SOURCE

ScienceDaily (Oct. 1, 2009) — Climate change wreaked havoc on the Earth’s first rainforests but they quickly bounced back, scientists reveal. The findings of the research team, led by Dr Howard Falcon-Lang from Royal Holloway, University of London, are based on spectacular discoveries of 300-million-year-old rainforests in coal mines in Illinois, USA.

Preserved over vast areas, these fossilized rainforests in Illinois are the largest of their kind in the world. The rocks at this site - in which the rainforests occur - contain evidence for climate fluctuations. During cold ‘ice ages’, fossils show that the tropics dried out and rainforests were pushed to the brink of extinction. However, rainforests managed to recover and return to their former glory.
Dr Falcon-Lang, from the Department of Earth Sciences, worked with colleagues at the Smithsonian Institution and Illinois Geological Survey. In their paper published in the journal Geology, they show that rainforest species all but vanished at the height of the ice ages. Yet they also reveal that the coal beds that formed shortly after, as the climate warmed, contain abundant rainforest species.
Falcon-Lang said, ‘These discoveries radically change our understanding of the Earth’s first rainforests. We used to think these were stable ecosystems, unchanged for tens of millions of years. Now we know they were incredibly dynamic, constantly buffeted by climate change’.
The research may also shed light on how climate change will affect the Amazon rainforest in the future. Dr Falcon-Lang commented, ‘If we can understand how climate shaped rainforests in the distant past, we can infer how they will respond in the future. We’ve shown that within certain limits, rainforests are resilient to climate change; however, extreme climate change may push rainforests beyond a point of no return’.
The work is part of a five-year project funded by the UK’s Natural Environment Research Council and aims to study how climate change affected the Earth’s first rainforests. These ancient rainforests date from the Carboniferous period, 300 million years ago, when most of the world's coal resources were formed.
Adapted from materials provided by University of Royal Holloway London, via AlphaGalileo.

Archaeologists Discover Amphitheatre In Excavation Of Portus, Ancient Port Of Rome.

SOURCE

ScienceDaily (Oct. 1, 2009) — University of Southampton archaeologists leading a major excavation of Portus, the ancient port of Rome, have uncovered the remains of an amphitheatre-shaped-building, solving a mystery which has puzzled experts for over 140 years.

The excavation team, working in collaboration with the British School at Rome, is conducting the first ever large-scale dig at Portus on the banks of a hexagonal shaped man-made lake which formed the 2nd century harbour, near the Italian capital.
"When the site was visited by archaeologist Rodolfo Lanciani in the 1860s he marked on his plans the remains of a theatre, but subsequently no trace of the building could be found," says Portus Project Director and leading expert in Roman Archaeology at the University of Southampton, Professor Simon Keay.
"Our team has rediscovered this 'theatre' and proved it was in fact a building more akin to an amphitheatre. Lanciani had only found half of the structure, leading him to misinterpret its shape and function."
Funded by the Arts and Humanities Research Council, experts from Southampton have been working with colleagues from the BSR, The Italian Archaeological Superintendency for Ostia and the University of Cambridge, to carry out extensive excavation at Portus. They have uncovered a large Roman warehouse, the 'amphitheatre' and what the team have identified as an Imperial palace. This is likely to have played host to renowned emperors such as Hadrian.
Portus was Rome's gateway to the Mediterranean for most of the Imperial period and played a key role in funnelling food, slaves, wild animals, marble and all manner of luxury goods from across the Mediterranean and beyond to the citizens of Rome. It was vital to the survival of the Empire and the only real 'transport hub' serving the city.
"The 'amphitheatre' we have discovered was similar in ground area to the Pantheon in Rome, but it is unclear exactly what it was used for," continues Professor Keay.
"Gladiatorial combat may have taken place there - wild beast baiting, the staging of mock sea battles, or it may have been a form of Roman 'folly', shaped like an amphitheatre, but used as a monumental garden. It is unusual to find this type of building so close to a harbour."
Having solved one riddle, archaeologists have now uncovered another; the white marble head of a statue unearthed at the site of once-luxurious rooms close to the 'amphitheatre'. It is thought the head dates back to the 2nd or early 3rd century, however it is less clear who it depicts.
"The elderly bearded male wearing a flat skull-cap could suggest it is Ulysses, however it is equally possible it is a representation of one of the Greek sailors who accompanied him on his travels. For the moment his identity remains a mystery," concludes Professor Keay.
Part of the 'Portus Project' involves the work of the University of Southampton's Archaeological Computing Research Group. They are producing computer generated images which bring the port to life and provide archaeologists with a valuable 'tool' with which to explore the site. The University of Southampton and the BSR are jointly using ground-penetrating radar and other techniques to map buried buildings and other structures. The Portus Project has also been undertaking a geophysical survey of the Isola Sacra, an island to the south of Portus, and has found a major new canal and traces of Rome's marble yards.
Research has been underway at Portus for several years and Professor Keay hopes to continue working there. "This is one of the most important archaeological sites in the world," he says.
"Certainly it should be rated alongside such wonders as Stonehenge and Angkor Wat in Cambodia. So much of this Imperial port has been preserved and there is much more to learn about its role in supplying Rome and in the broader economic development of the Roman Mediterranean."
Adapted from materials provided by University of Southampton, via AlphaGalileo.

Before 'Lucy,' There Was 'Ardi': First Major Analysis Of Early Hominid Published In Science.

SOURCE

ScienceDaily (Oct. 1, 2009) — In a special issue of Science, an international team of scientists has for the first time thoroughly described Ardipithecus ramidus, a hominid species that lived 4.4 million years ago in what is now Ethiopia.

This research, in the form of 11 detailed papers and more general summaries, will appear in the journal's 2 October 2009 issue. Science is published by AAAS, the nonprofit science society.
This package of research offers the first comprehensive, peer-reviewed description of the Ardipithecus fossils, which include a partial skeleton of a female, nicknamed "Ardi."
The last common ancestor shared by humans and chimpanzees is thought to have lived six or more million years ago. Though Ardipithecus is not itself this last common ancestor, it likely shared many of this ancestor's characteristics. For comparison, Ardipithecus is more than a million years older than the "Lucy" female partial skeleton of Australopithecus afarensis. Until the discovery of the new Ardipithecus remains, the fossil record contained scant evidence of other hominids older than Australopithecus.
Through an analysis of the skull, teeth, pelvis, hands, feet and other bones, the researchers have determined that Ardipithecus had a mix of "primitive" traits, shared with its predecessors, the primates of the Miocene epoch, and "derived" traits, which it shares exclusively with later hominids.
Because of its antiquity, Ardipithecus takes us closer to the still-elusive last common ancestor. However, many of its traits do not appear in modern-day African apes. One surprising conclusion, therefore, is that it is likely that the African apes have evolved extensively since we shared that last common ancestor, which thus makes living chimpanzees and gorillas poor models for the last common ancestor and for understanding our own evolution since that time.
"In Ardipithecus we have an unspecialized form that hasn't evolved very far in the direction of Australopithecus. So when you go from head to toe, you're seeing a mosaic creature, that is neither chimpanzee, nor is it human. It is Ardipithecus," said Tim White of the University of California Berkeley, who is one of the lead authors of the research.
"With such a complete skeleton, and with so many other individuals of the same species at the same time horizon, we can really understand the biology of this hominid," said Gen Suwa of the University of Tokyo, Project paleoanthropologist and also a lead Science author.
"These articles contain an enormous amount of data collected and analyzed through a major international research effort. They throw open a window into a period of human evolution we have known little about, when early hominids were establishing themselves in Africa, soon after diverging from the last ancestor they shared with the African apes," said Brooks Hanson, deputy editor, physical sciences, at Science.
"Science is delighted to be publishing this wealth of new information, which gives us important new insights into the roots of hominid evolution and into what makes humans unique among primates," said Hanson.
The special collection of Science articles begins with an overview paper that summarizes the main findings of this research effort. In this article, White and his coauthors introduce their discovery of over 110 Ardipithecus specimens including a partial skeleton with much of the skull, hands, feet, limbs and pelvis. This individual, "Ardi," was a female who weighed about 50 kilograms and stood about 120 centimeters tall.
Until now, researchers have generally assumed that chimpanzees, gorillas and other modern African apes have retained many of the traits of the last ancestor they shared with humans – in other words, this presumed ancestor was thought to be much more chimpanzee-like than human-like. For example, it would have been adapted for swinging and hanging from tree branches, and perhaps walked on its knuckles while on the ground.
Ardipithecus challenges these assumptions, however. These hominids appear to have lived in a woodland environment, where they climbed on all fours along tree branches – as some of the Miocene primates did -- and walked, upright, on two legs, while on the ground. They do not appear to have been knuckle-walkers, or to have spent much time swinging and hanging from tree-branches, especially as chimps do. Overall, the findings suggest that hominids and African apes have each followed different evolutionary pathways, and we can no longer consider chimps as "proxies" for our last common ancestor.
"Darwin was very wise on this matter," said White.
"Darwin said we have to be really careful. The only way we're really going to know what this last common ancestor looked like is to go and find it. Well, at 4.4 million years ago we found something pretty close to it. And, just like Darwin appreciated, evolution of the ape lineages and the human lineage has been going on independently since the time those lines split, since that last common ancestor we shared," White said.
This special issue of Science includes an overview article, three articles that describe the environment Ardipithecus inhabited, five that analyze specific parts of Ardipithecus' anatomy, and two that discuss what this new body of scientific information may imply for human evolution.
Altogether, forty-seven different authors from around the world contributed to the total study of Ardipithecus and its environment. The primary authors are Tim White of the University of California, Berkeley, Berhane Asfaw of Rift Valley Research Service in Addis Ababa, Giday WoldeGabriel of Los Alamos National Laboratory, Gen Suwa of the University of Tokyo, and C. Owen Lovejoy of Kent State University.
"These are the results of a mission to our deep African past," said WoldeGabriel, who is also Project co-Director and geologist.
This research was funded by the National Science Foundation, the Institute of Geophysics and Planetary Physics of the University of California at Los Alamos National Laboratory (LANL), the Japan Society for the Promotion of Science, and others.
Adapted from materials provided by American Association for the Advancement of Science, via EurekAlert!, a service of AAAS.

Was Mighty T. Rex 'Sue' Felled By A Lowly Parasite?

SOURCE

ScienceDaily (Sep. 30, 2009) — When pondering the demise of a famous dinosaur such as 'Sue,' the mighty Tyrannosaurus rex whose fossilized remains are a star attraction of the Field Museum in Chicago, it is hard to avoid the image of clashing Cretaceous titans engaged in bloody, mortal combat.

It is an image commonly promoted by museums and dinosaur aficionados. Sue's remains, in fact, exhibit holes in her jaw that some believed were battle scars, the result of conflict with another dinosaur, possibly another T. rex.
But a new study, published in the online journal PLoS ONE, provides evidence that Sue, perhaps the most famous dinosaur in the world, was felled in more mundane fashion by a lowly parasite that still afflicts modern birds. The study, conducted by an international team of researchers led by Ewan D.S. Wolff of the University of Wisconsin-Madison and Steven W. Salisbury of the University of Queensland, Australia, pins the demise of Sue and other tyrannosaurs with similar scars on an avian parasitic infection called trichomonosis, caused by a single-celled parasite that causes similar pathologies on the mandibles of modern birds, raptors in particular.
It is possible the infection in her throat and mouth may have been so acute that the 42-foot-long, 7-ton dinosaur starved to death, says Wolff, a vertebrate paleontologist and a third-year student at the UW-Madison School of Veterinary Medicine. Co-authors of the study include famed paleontologist John R. Horner of the Museum of the Rockies, which funded the study, and David J. Varricchio of Montana State University.
The focus of the new study was a survey of lesions on the jaws of Sue and nine other tyrannosaur specimens. The lesions had previously been attributed to bite wounds or, possibly, a bacterial infection.
"What drew my attention to trichomonosis as a potential candidate for these mysterious lesions on the jaws of tyrannosaurs is the manifestation of the effects of the disease in [bird] raptors," explains Wolff. "When we started looking at trichomonosis in greater depth, there was a story that matched some lines of evidence for transmission of the disease in tyrannosaurs."
In birds, trichomonosis is caused by a protozoan parasite called Trichomonas gallinae. It can be transmitted from birds such as pigeons, which commonly carry the parasite but often suffer few ill effects, to raptors such as falcons and hawks, where it causes serious lesions in the mandibles. The pattern of lesions, says Wolff, closely matches the holes in the jaws of tyrannosaurs and occurs in the same anatomical location.
The scars of combat among tyrannosaurs and other dinosaurs, Wolff notes, are not uncommon, but differ notably from the lesions that are the focus of the current study. The holes caused by trichomonosis tend to be neat and have relatively smooth edges, while bite marks are often messy, and they scar and puncture bone in ways that are not readily comparable.
Tyrannosaurs, notes Wolff, are known to have been gregarious, intermingling, fighting amongst themselves, and sometimes eating one another. Transmission of the parasite may have been through salivary contact or cannibalism, he says, noting that there is no known evidence of trichomonosis in other dinosaurs.
"This leads us to suspect that tyrannosaurs might have been the source of the disease and its transmission in its environment," Wolff says.
For the disease to manifest itself in the jaws of Sue and other tyrannosaurs, it would have had to be at an advanced stage as the parasite typically sets up housekeeping as a film in the back of the throat.
"The lesions we observe on Sue suggest a very advanced stage of the disease and may even have been the cause of her demise," says Wolff. "It is a distinct possibility as it would have made feeding incredibly difficult. You have to have a viable pharynx. Without that, you won't make it for very long, no matter how powerful you are."
Journal reference:
Ewan D. S. Wolff, Steven W. Salisbury, John R. Horner, David J. Varricchio. Common Avian Infection Plagued the Tyrant Dinosaurs. PLoS ONE, 2009; 4(9): e7288 DOI: 10.1371/journal.pone.0007288
Adapted from materials provided by University of Wisconsin-Madison.

Human Spear Likely Cause Of Death Of Neandertal

SOURCE

ScienceDaily (July 22, 2009) — The wound that ultimately killed a Neandertal man between 50,000 and 75,000 years was most likely caused by a thrown spear, the kind modern humans used but Neandertals did not, according to Duke University-led research.

"What we've got is a rib injury, with any number of scenarios that could explain it," said Steven Churchill, an associate professor of evolutionary anthropology at Duke. "We're not suggesting there was a blitzkrieg, with modern humans marching across the land and executing the Neandertals. I want to say that loud and clear."
But Churchill's analysis indicates the wound was from a thrown spear, and it appears that modern humans had a thrown-weapons technology and Neandertals didn't. "We think the best explanation for this injury is a projectile weapon, and given who had those and who didn't that implies at least one act of inter-species aggression."
Churchill is the first author of a new report now posted online in the Journal of Human Evolution on the long-ago incident in what is now Iraq. He and four other investigators used a specially calibrated crossbow, copies of ancient stone points and numerous animal carcasses to make their deductions.
Neandertals, stoutly-built and human-like, lived at the same time and in the same areas as some modern humans before going extinct. Anthropologists have been puzzling over Neandertal's fate for many years, proposing that perhaps they inter-bred with modern humans, failed to compete for food or resources, or were possibly hunted to extinction by the humans.
While narrowing the range of possible causes for the Iraqi Neandertal's wound, and raising the possibility of an encounter between humans and a now-extinct close cousin, the research does not definitively conclude who did it, or why.
The victim was one of nine Neandertals discovered between 1953 and 1960 in a cave in northeastern Iraq's Zagros Mountains. Now called "Shanidar 3," he was a 40- to 50-year-old male with signs of arthritis and a sharp, deep slice in his left ninth rib.
The wounded Neandertal's rib had apparently started healing before he died. Comparing the wound to medical records from the American Civil War, a time before modern antibiotics, suggested to the researchers that he died within weeks of the injury, perhaps due to associated lung damage from a stabbing or piercing wound.
"People have been speculating about that rib injury for going on 50 years now," Churchill said. "Some said it was interpersonal violence. Others said it could have been an accident. Did it involve only Neandertals? Now we, for the first time, have brought some experimental evidence to bear on these questions."
While scientists have been unable to precisely date the remains, Shanidar 3 could have lived and died as recently as 50,000 years ago. If so, he could have encountered modern humans who were just returning to the area then after a 30,000-year hiatus.
Archaeological evidence also suggests that by 50,000 years ago humans, but not their Neandertal cousins, had developed projectile hunting weapons, Churchill said. They used spear throwers, detachable handles that connected with darts and spears to effectively lengthen a hurler's arm and give the missiles a power boost.
As human weapons technology advanced, Neandertals continued using long thrusting spears in hunting, which they probably tried -- for personal safety -- to keep between themselves and their prey instead of hurling them, Churchill added.
Both Neandertals and humans were also armed with stone knives. And both species had developed techniques for making sharp stone points.
Looking back at this Paleolithic cold case, the study's authors evaluated all the possible causes of the rib wound with the aid of contemporary tools.
The injury is "consistent with a number of scenarios, including wounding from a long-range projectile (dart) weapon, knife stab, self-inflicted accidental injury and accidental stabbing by a hunting partner," the report said.
Drawing from studies aimed at improving police and prison guard protection, the researchers concluded that the downward sweep of a knife could have the correct trajectory to produce Shanidar 3's rib injury. "Knife attacks generally involve a relatively higher kinetic energy," the report said. However, "whatever created that puncture was carrying fairly low kinetic energy at a low momentum," said Churchill. "That's consistent with a spear-thrower delivered spear."
The investigators rigged up a special crossbow to fire stone-age projectiles, using calibration marks on the crossbow to tell them how much force they were delivering with each launch.
Those tests revealed the delivered energy needed to create similar wounds in the ribs of pig carcasses, which the researchers used as an approximation of a Neandertal's body.
The researchers also used measurements from a 2003 study to estimate the impact of using a thrusted rather than thrown spear, the kind of jabbing that Neandertals are thought to have employed. That produced higher kinetic energies and caused more massive rib damage than Shanidar 3 sustained.
Another clue was the angle of the wound. Whatever nicked his rib entered the Neandertal's body at about 45 degrees downward angle. That's consistent with the "ballistic trajectory" of a thrown weapon, assuming that Shanidar 3 -- who was about 5 feet, 6 inches tall -- was standing, Churchill said.
Shanidar 3 is one of two known Neandertal skeletons bearing evidence of a possible stone tool injury. The other remains, found in France, had an almost-healed head wound. That individual is known to have lived "at a time of overlap with modern humans we call the Cro-Magnon," Churchill said.
The study was funded by the National Science Foundation, the L.S.B. Leakey Foundation and the University of New Mexico. Other co-authors of the Journal of Human Evolution report include Robert Franciscus, an associate professor of anthropology at the University of Iowa; and three Duke alumni who assisted Churchill as undergraduates -- Hilary McKean-Peraza, Julie Daniel and Brittany Warren.
Adapted from materials provided by Duke University.

Ancient Humans Left Evidence From The Party That Ended 4,000 Years Ago

SOURCE

ScienceDaily (July 22, 2009) — The party was over more than 4,000 years ago, but the remnants still remain in the gourds and squashes that served as dishware. For the first time, University of Missouri researchers have studied the residues from gourds and squash artifacts that date back to 2200 B.C. and recovered starch grains from manioc, potato, chili pepper, arrowroot and algarrobo. The starches provide clues about the foods consumed at feasts and document the earliest evidence of the consumption of algarrobo and arrowroot in Peru.

"Archaeological starch grain research allows us to gain a better understanding of how ancient humans used plants, the types of food they ate, and how that food was prepared," said Neil Duncan, doctoral student of anthropology in the MU College of Arts and Science and lead author of the study that was published in the Proceedings of the National Academy of Science (PNAS). "This is the first study to analyze residue from bottle gourd or squash artifacts. Squash and bottle gourds had a variety of uses 4,000 years ago, including being used as dishes, net floats and symbolic containers. Residue analysis can help determine the specific use."
In the study, researchers recovered starch grains from squash and gourd artifacts by a method that currently is used to recover microfossils from stone tools and ceramics. First, the artifact was placed in a special water bath to loosen and remove adhering residue. Then the artifact's interior surface was lightly brushed to remove any remaining residue. The residues were collected, and starch grains were isolated from each of these sediments.
"The starch residues of edible plants found on the artifacts and the special archaeological context from which these artifacts were recovered suggest that the artifacts were used in a ritual setting for the serving and production of food," Duncan said. "The method used in this study could be used in other areas and time periods in which gourds and squash rinds are preserved."
Scientists believe the Buena Vista site, where the starch grains were recovered, served as a small ceremonial center in the central Chillon Valley. The social and ritual use of food is not well understood during this time period in Peru, but this research will enhance the potential for understanding, Duncan said.
The study, "Gourd and squash artifacts yield starch grains of feasting foods from preceramic Peru," is coauthored by Duncan; Deborah Pearsall, professor of anthropology; and Robert Benfer, emeritus professor of anthropology.
Journal reference:
Neil Duncan et al. Gourd and squash artifacts yield starch grains of feasting foods from preceramic Peru. Proceedings of the National Academy of Science, July 21, 2009
Adapted from materials provided by University of Missouri-Columbia.

Could Cannon Balls From The Early 19th Century Sink Warships?

SOURCE

ScienceDaily (July 16, 2009) — A joint experiment by researchers at the University of Haifa and Rafael Advanced Defense Systems Ltd. succeeded in solving the riddle: Could cannon balls from the early 19th century sink warships?

At first glance, the hull of the warship that sank off the coast of Acre seemed strong; but a unique experiment indicated that the thick timbers could not withstand the cannon balls.
A joint experiment carried out by researchers from the Leon Recanati Institute for Maritime Studies at the University of Haifa and staff of Rafael Advanced Defense Systems Ltd. has solved the riddle that has been puzzling researchers ever since they first observed the thick wooden sides of the sunken ship opposite the shore of Acre: could cannon fire have penetrated the hull?
The ship was discovered in 1966, but only since University of Haifa researchers began examining it about three years ago have its mysteries been exposed. The initial matters of interest related to the ship's origins, date and the reason why it sank. A map drawn up by a British officer in 1799, during Napoleon's siege of Acre, led the researchers to assume that this was a blockship sunk by the British to bar French vessels from entering the port.
Another puzzle that has occupied the researchers, however, relates to the thickness of the ship's hull. According to Dr. Yaacov Kahanov, who heads the research team, it was evident at first glance that the hull, which was constructed of oak, was unusually thick, leading the team to question the possibility of cannon-ball penetration. Experimental firings of cannons at replicas of wooden warships have been carried out in other countries, but due to the cost and complexity of such experiments, they have been few and far between. In general, they were only firing demonstrations, and scientific data has not always been obtained. So it was still hard to tell for sure whether the cannon balls found in the wreck would have been capable of sinking this particular ship.
The University of Haifa marine researchers received assistance from a team of Rafael engineers, who developed a unique model that enabled firing experiments to be carried out on a reduced scale, thereby reducing costs, and enabling controlled, measured and documented experimentation. The present experiment was carried out at a scale of 1:2, for which five models of the ship's hull, based on the archaeological findings, were constructed at the University. In parallel, Rafael adapted an experimental gun to fire steel balls, modeling the cannon balls. Meticulous measurements were taken to ensure setting the range of muzzle velocities of the period; 100-500 meters per second.
The experiments showed in the most dramatic way that, despite the hull's strength, it could not withstand the impact of the cannon fire, which penetrated it even at the lowest velocities. It also became evident that the lower the velocity, the more energy was absorbed in causing damage to the hull, and the more the wood splintered, which would have caused more harm to the ship's personnel. The results of this experiment, according to the researchers, are of much significance to the study of the vessel and to the study of naval battles in this period.
Adapted from materials provided by University of Haifa, via EurekAlert!, a service of AAAS.

Crocodile Skull Unearthed At Arlington Archosaur Site In Texas

SOURCE

ScienceDaily (July 15, 2009) — Paleontologists have made the most important discovery to date at the Arlington Archosaur Site, a prolific fossil site in North Arlington, Texas. The disassembled skull of a crocodile with two and a half inch long teeth that lived nearly 100 million years ago has been unearthed.

"We have over 50 bones exposed," said The University of Texas at Arlington dinosaurs lecturer Derek Main, who heads the project. "They are truly impressive. The teeth measure 6.5 centimeters, larger than my thumb."
To date, more dinosaur fossils have been recovered from the Arlington Archosaur Site, where excavation began little more than a year ago, than from any other site in the Dallas-Fort Worth area. The site lies within Cretaceous rocks, formed 95 million years ago when Arlington was the beachhead for a giant sea that divided the continent.
The site has yielded fossils from various species of animals, including dinosaurs. A skeleton of a large herbivorous "duck billed" dinosaur was excavated from the northern hillside at the site. Crocodile fossils are among the most commonly found.
Main said the site is unique because it is a major dinosaur excavation in the middle of a large metropolitan setting and it preserves many fossils from different animals. he site also has fossils from turtles, lungfish, fish and sharks. The excavation of the Arlington Archosaur Site began in the spring of 2008 when the Huffines Group obtained the property and granted land access to UT Arlington.
Adapted from materials provided by University of Texas At Arlington.

Last Supper Of The Hominids Establishes Times They Lived At Sites

SOURCE

ScienceDaily (July 15, 2009) — In the French cave of Arago, an international team of scientists has analyzed the dental wear of the fossils of herbivorous animals hunted by Homo heidelbergensis. It is the first time that an analytical method has allowed the establishment of the length of human occupations at archaeological sites. The key is the last food that these hominids consumed.

For many years, the mobility of the groups of hominids and how long they spent in caves or outdoors has been a subject of discussion among scientists. Now, an international team headed by researchers from the Catalan Institute of Human Paleoecology and Social Evolution (IPHES) in Tarragona has based its studies on the dental fossils of animals hunted by hominids in order to determine the vegetation in the environment and the way of life of Homo heidelbergensis.
Florent Rivals is the main author and a researcher from the Catalan Institute for Research and Advanced Studies (ICREA), attached to the IPHES in Tarragona. "For the first time, a method has been put forward which allows us to establish the relative length of the human occupations at archaeological sites as, up until now, it was difficult to ascertain the difference between, for example, a single long-term occupation and a succession of shorter seasonal occupations in the same place", he explained to SINC.
In the study, recently published in the Journal of Human Evolution, the researchers analyze the dental wear of the ungulates (herbivorous mammals) caused by microscopic particles of opaline silica in plants. These marks appear when eating takes place and erase the previous ones. This is why they are so useful.
Thanks to the "last supper phenomenon", the scientists have been able to analyze the last food consumed by animals such as the Eurasian wild horse (Equus ferus), the mouflon (Ovis ammon antiqua) and the reindeer (Rangifer tarandus). "This method allows us to confirm the seasonal nature of the occupation", Rivals added. According to the team, the microwear of the teeth is sensitive to seasonal changes in the diet.
The application has allowed the researchers to estimate the length of the occupation of the site from the Lower Paleolithic Age in the cave of Arago (France) by the number of marks on the fossils and, therefore, the variation in the diet of several species of herbivores, as "each season presented food resources which were limited and different in the environment", the paleontologist clarified.
High and low periods of occupation
After confirming the hypothesis in present-day animals whose age and date of death was known to the scientists, the researchers demonstrated that, if a group of animals is seen during a specific season (a short-term occupation), the signs of dental wear undergo little variation. But if the occupation lasts several seasons, the dental marks are more diverse.
"If the animals are hunted during long periods of occupation, more variable dental wear would be expected", Rivals declared. In the case of the French cave of Arago, the study of the dental wear confirms that it was occupied in different ways. "With this method, we were able to prove that at the site, which belonged to Homo heidelbergensis, there is evidence of differing mobility, as there were highly mobile groups and others with little mobility", the scientist confirmed.
The Spanish and German researchers have combined this application with multidisciplinary studies of archaeological sites in order to apply it to other settlements of the Mid-Paleolithic Age such as Payre (France), Taubach (Germany) and Abric Romani (Spain).
Journal reference:
Rivals et al. A new application of dental wear analyses: estimation of duration of hominid occupations in archaeological localities. Journal of Human Evolution, 2009; 56 (4): 329 DOI: 10.1016/j.jhevol.2008.11.005
Adapted from materials provided by FECYT - Spanish Foundation for Science and Technology.

Sharks: Missing Piece Of Fossil Puzzle Found

SOURCE

ScienceDaily (July 14, 2009) — The mode of reproduction seen in modern sharks is nearly 400 million years old. That is the conclusion drawn by Professor Per Erik Ahlberg, Uppsala University, from his discovery of a so-called "clasper" in a primitive fossil fish earlier this year. The research results are published in Nature.

In February this year, a paper published in Nature by a team of Australian and British researchers showed that placoderms, a group of ancient fishes that died out more than 350 million years ago, gave birth to live young. Beautifully preserved fossil embryos in the body cavity of the placoderm Incisoscutum showed that these fishes, close to the common origin of all jawed vertebrates, had a mode of reproduction similar to modern sharks.
Live birth requires internal fertilization. Sharks achieve this by using a "clasper", an extension of the pelvic fin that functions like a penis. The authors looked for a clasper in their placoderm fossils but couldn't find one, so they were forced to argue that it had been made of soft cartilage and had not been preserved.
Shortly afterwards, Per Erik Ahlberg from Uppsala University visited one of the Australian researchers and spotted a perfectly preserved bony clasper in one of their Incisoscutum fossils.
"It was lying in plain view but had been misinterpreted as part of the pelvis and overlooked," he says.
Together with the original authors he is publishing a short paper in the journal Nature that presents this missing piece of the puzzle and completes the picture of placoderm reproduction from mating to birth.
"It provides a pedigree of nearly 400 million years for the "advanced" and seemingly specialized reproductive biology of modern sharks," says Per Ahlberg.
Journal reference:
Per Ahlberg, Kate Trinajstic, Zerina Johanson & John Long. Pelvic claspers confirm chondrichthyan-like internal fertilization in arthrodires. Nature, 2009; DOI: 10.1038/nature08176
Adapted from materials provided by Uppsala University.

Down Under Dinosaur Burrow Discovery Provides Climate Change Clues

SOURCE

ScienceDaily (July 11, 2009) — On the heels of his discovery in Montana of the first trace fossil of a dinosaur burrow, Emory University paleontologist Anthony Martin has found evidence of more dinosaur burrows – this time on the other side of the world, in Victoria, Australia. The find, to be published this month in Cretaceous Research, suggests that burrowing behaviors were shared by dinosaurs of different species, in different hemispheres, and spanned millions of years during the Cretaceous Period, when some dinosaurs lived in polar environments.

"This research helps us to better understand long-term geologic change, and how organisms may have adapted as the Earth has undergone periods of global cooling and warming," says Martin, a senior lecturer in environmental studies at Emory. Martin is also an honorary research associate at Monash University in Melbourne.
In 2006, in collaboration with colleagues from Montana State University and Japan, Martin identified the 95-million-year-old skeletal remains of a small adult dinosaur and two juveniles in a fossilized burrow in southwestern Montana. They later named the dinosaur species Oryctodromeus cubicularis, meaning "digging runner of the lair."
The researchers hypothesized that, besides caring for young in their dens, burrowing may have allowed some dinosaurs to survive extreme environments – throwing a wrench in some extinction theories.
A year after the Montana find, Martin traveled to the Victoria coast, which marks the seam where Australia once snuggled against Antarctica. Lower Cretaceous strata of Victoria have yielded the best-documented assemblage of polar dinosaur bones in the world.
During a hike to a remote site known as Knowledge Creek, west of Melbourne, Martin rounded the corner of an outcropping and was astounded to see, right at eye level, the trace fossil of what appeared to be a burrow almost identical to the one he had identified in Montana. "I stared at it for a long time," recalls Martin. "In paleontology, the saying, 'where luck meets preparation' really holds true."
The probable burrow etched into the Early Cretaceous outcrop is about six-feet long and one-foot in diameter. It gently descends in a semi-spiral, ending in an enlarged chamber. Martin later found two similar trace fossils in the same area.
Last period of global warming
The Victoria fossils are about 110 million years old, around the time that Australia split with Antarctica, and dinosaurs roamed in prolonged polar darkness along forested southern Australia river plains. It was one of the last times the Earth experienced global warming, with an average temperature of 68 degrees Fahrenheit – about 10 degrees higher than today.
During the polar winter, though, the temperature could plunge below freezing. Previously, researchers theorized that the small dinosaurs in the region survived harsh weather by sheltering beneath large tree roots or in hollows. Martin's find, however, indicates that they may have dug into the soft banks of rivers flowing out of the rift valley.
The age, size and shape of the likely burrows led Martin to hypothesize that they were made by small ornithopod dinosaurs – herbivores that were prevalent in the region. These ornithopods stood upright on their hind legs and were about the size of a large, modern-day iguana.
"It's fascinating to find evidence connecting a type of behavior between dinosaurs that are probably unrelated, and lived in different hemispheres during different times," Martin says. "It fills in another gap in our understanding of the evolution of dinosaurs, and ways they may have survived extreme environments."
An eye for subtle clues
A specialist in trace fossils – including tracks, scat and burrows – Martin is known for detecting subtle paleontology clues. He also identified the first tracks of a large, carnivorous dinosaur in Victoria, and the first fossil crayfish burrows from the same area.
Martin teaches a seminar at Emory on modern-day animal tracking, a skill that he says aids him in finding signs of prehistoric life. "It's important to do as much field work as possible, because it gives your mind a better library of search images," he says.
Adapted from materials provided by Emory University.