New species of Allosaurus discovered in Utah

A remarkable new species of meat-eating dinosaur has been unveiled at the Natural History Museum of Utah. Paleontologists unearthed the first specimen in early 1990s in Dinosaur National Monument in northeastern Utah. The huge carnivore inhabited the flood plains of western North America during the Late Jurassic Period, between 157-152 million years ago, making it the geologically oldest species of Allosaurus, predating the more well-known state fossil of Utah, Allosaurus fragilis. The newly named dinosaur Allosaurus jimmadseni, was announced today in the open-access journal PeerJ.

Allosaurus jimmadseni attack juvenile sauropod
[Credit: Todd Marshall]

The species belongs to the allosauroids, a group of small to large-bodied, two-legged carnivorous dinosaurs that lived during the Jurassic and Cretaceous periods. Allosaurus jimmadseni, possesses several unique features, among them a short narrow skull with low facial crests extending from the horns in front of the eyes forward to the nose and a relatively narrow back of the skull with a flat surface to the bottom of the skull under the eyes. The skull was weaker with less of an overlapping field of vision than its younger cousin Allosaurus fragilis. Allosaurus jimmadseni evolved at least 5 million years earlier than fragilis, and was the most common and the top predator in its ecosystem. It had relatively long legs and tail, and long arms with three sharp claws. The name Allosaurus translates as "different reptile," and the second part, jimmadseni, honors Utah State Paleontologist James H. Madsen Jr.

Following an initial description by Othniel C. Marsh in 1877, Allosaurus quickly became the best known--indeed the quintessential--Jurassic theropod. The taxonomic composition of the genus has long been a debate over the past 130 years. Paleontologists argue that there are anywhere between one and 12 species of Allosaurus in the Morrison Formation of North America. This study recognizes only two species--A. fragilis and A. jimmadseni.

"Previously, paleontologists thought there was only one species of Allosaurus in Jurassic North America, but this study shows there were two species--the newly described Allosaurus jimmadseni evolved at least 5 million years earlier than its younger cousin, Allosaurus fragilis," said co-lead author Mark Loewen, research associate at the Natural History Museum of Utah, and associate professor in the Department of Geology and Geophysics at the University of Utah led the study. "The skull of Allosaurus jimmadseni is more lightly built than its later relative Allosaurus fragilis, suggesting a different feeding behavior between the two."

"Recognizing a new species of dinosaur in rocks that have been intensely investigated for over 150 years is an outstanding experience of discovery. Allosaurus jimmadseni is a great example of just how much more we have to learn about the world of dinosaurs. Many more exciting fossils await discovery in the Jurassic rocks of the American West," said Daniel Chure, retired paleontologist at Dinosaur National Monument and co-lead author of the study.

George Engelmann of the University of Nebraska, Omaha initially discovered the initial skeleton of the new species within Dinosaur National Monument in 1990. In 1996, several years after the headless skeleton was collected, the radioactive skull belonging to the skeleton using a radiation detector by Ramal Jones of the University of Utah. Both skeleton and skull were excavated by teams from Dinosaur National Monument.

"Big Al," another specimen belonging to the new species, was discovered in Wyoming on United States Bureau of Land Management (BLM) land in 1991 and is housed in the collections of the Museum of The Rockies in Bozeman, Montana. Previously thought to belong to Allosaurus fragilis, "Big Al" was featured in the BBC's 2001 "Walking with Dinosaurs: Ballad of Big Al" video. Over the last 30 years, crews from various museums have collected and prepared materials of this new species. Other specimens include "Big Al Two" at the Saurier Museum Aathal in Switzerland and Allosaurus material from the Dry Mesa Quarry of Colorado at Brigham Young University.

"This exciting new study illustrates the importance of continued paleontological investigations on public lands in the West. Discovery of this new taxon of dinosaur will provide important information about the life and times of Jurassic dinosaurs and represents another unique component of America's Heritage," said Brent Breithaupt, BLM regional paleontologist.

Paleontologist James Madsen Jr assembles a composite skeleton of Allosaurus from the Clevland
Lloyd Dinosaur Quarry [Credit: J. Willard Marriot Library at the University of Utah]

Early Morrison Formation dinosaurs were replaced by some of the most iconic dinosaurs of the Late Jurassic

Allosaurus jimmadseni lived on the semi-arid Morrison Formation floodplains of the interior of western North America. The older rocks of the Morrison Formation preserve a fauna of dinosaurs distinct from the iconic younger Morrison Formation faunas that include Allosaurus fragilis, Diplodocus and Stegosaurus. Paleontologists have recently determined that specimens of this new species of dinosaur lived in several places throughout the western interior of North America (Utah, Colorado and Wyoming).

Study summary

Dinosaurs were the dominant members of terrestrial ecosystems during the Mesozoic. However, the pattern of evolution and turnover of ecosystems during the middle Mesozoic remains poorly understood. The authors report the discovery of the earliest member of the group of large-bodied allosauroids in the Morrison Formation ecosystem that was replaced by Allosaurus fragilis and illustrate changes acquired in the genus over time. The study includes an in-depth description of every bone of the skull and comparisons with the cranial materials of other carnivorous dinosaurs. Finally, the study recognizes just two species of Allosaurus in North America with Allosaurus fragilis replacing its earlier relative Allosaurus jimmadseni.

Fact sheet: Major points of the paper

- A remarkable new species of meat-eating dinosaur, Allosaurus jimmadseni, is described based on two spectacularly complete skeletons. The first specimen was unearthed in Dinosaur National Monument, in northeastern Utah.

- Allosaurus jimmadseni is distinguished by a number of unique features, including low crests running from above the eyes to the snout and a relatively narrow back of the skull with a flat surface to the bottom of the upper skull under the eyes. The skull was weaker with less of an overlapping field of vision than its younger cousin Allosaurus fragilis.

- At 155 million years old, Allosaurus jimmadseni is the geologically-oldest species of Allosaurus predating the more well-known State Fossil of Utah Allosaurus fragilis.

- Allosaurus jimmadseni was the most common and the top predator in its ecosystem. It had relatively long legs and tail, and long arms with three sharp claws.

Study design

- Comparison of the bones with all other known allosauroid dinosaurs indicate that the species possessed unique features of the upper jaw and cheeks (maxilla and jugal) and a decorative crest stretching from just in front of the eyes to the nose.

- Many of the comparisons were made with the thousands of bones of Allosaurus fragilis collected from the famous Cleveland-Lloyd Dinosaur Quarry administered by the Bureau of Land Management that are housed in the collections of the Natural History Museum of Utah.

- On the basis of these features, the scientific team named it a new genus and species of dinosaur, Allosaurus jimmadseni (translating to "Jim Madsen's different reptile").

- Allosaurus jimmadseni is particularly notable for its slender, narrow skull with short sharp nasal crests compared to its close relative and successor Allosaurus fragilis.

- The study was funded in part by the University of Utah, the National Park Service and the National Science Foundation.

A cast of the skeleton and skull of Allosaurus jimmadseni as it was discovered and now on exhibit at Dinosaur
National Monument in Utah. The original skeleton was molded and cast before it was taken apart
and prepared for study and research [Credit: Dan Chure]

New dinosaur name: Allosaurus jimmadseni

- The first part of the name, Allosaurus, (a·luh·SAW·ruhs) can be translated from Greek as the "other", "strange" or "different" and "lizard" or "reptile" literally to "different reptile". The second part of the name jimmadseni (gym-MAD-sehn-eye) honors the late Utah State Paleontologist James Madsen Jr. who excavated and studied tens of thousands of Allosaurus bones from the famous Cleveland-Lloyd Dinosaur Quarry in central Utah and contributed greatly to the knowledge of Allosaurus.

Size

- Allosaurus jimmadseni was approximately 26 to 29 feet (8-9 meters) long.

- Allosaurus jimmadseni weighed around 4000 lbs. (1.8 metric tonnes).

Relationships

- Allosaurus jimmadseni belongs to a group of carnivorous dinosaurs called "allosauroids," the same group as the famous Allosaurus fragilis.

- Other dinosaurs found in rocks containing Allosaurus jimmadseni include the carnivorous theropods Torvosaurus and Ceratosaurus; the long-necked sauropods Haplocanthosaurus and Supersaurus; and the plate-backed stegosaur Hesperosaurus.

- Allosaurus jimmadseni is closely related to the State Fossil of Utah, Allosaurus fragilis.

Anatomy

- Allosaurus jimmadseni was a two-legged carnivore, with long forelimbs and sharp, recurved claws that were likely used for grasping prey.

- Like other allosauroid dinosaurs, Allosaurus jimmadseni had a large head full of 80 sharp teeth. It was also the most common carnivore in its ecosystem.

Age and geography

- Allosaurus jimmadseni lived during the Kimmeridgian stage of the Late Jurassic period, which spanned from approximately 157 million to 152 million years ago.

- Allosaurus jimmadseni lived in a semi-arid inland basin filled with floodplains, braided stream systems, lakes, and seasonal mudflats along the western interior of North America.

- Allosaurus jimmadseni represents the earliest species of Allosaurus in the world.

Three species of Allosaurus [Credit: Chure and Loewen, 2020]

Discovery

- Allosaurus jimmadseni can be found in a geologic unit known as the Salt Wash Member of the Morrison Formation and its equivalents exposed in Colorado, Wyoming, and Utah.

- The first specimen of Allosaurus jimmadseni was discovered in the National Park Service administered by Dinosaur National Monument in Uintah County, near Vernal, Utah.

- Allosaurus jimmadseni was first discovered by George Engelmann of the University of Nebraska, Omaha on July 15, 1990 during a contracted paleontological inventory of the Morrison Formation of Dinosaur National Monument.

- Another specimen of Allosaurus jimmadseni known as "Big Al," was found on land administered by the U.S. Department of the Interior's Bureau of Land Management in Wyoming.

- Further specimens of Allosaurus jimmadseni have been subsequently recognized in the collections of various museums.

- Allosaurus jimmadseni specimens are permanently housed in the collections of Dinosaur National Monument, Utah; the Museum of the Rockies, Bozeman, Montana; the Saurier Museum of Aathal, Switzerland; the South Dakota School of Mines, Rapid City, South Dakota; Brigham Young University's Museum of Paleontology, Provo, Utah; and the United States National Museum (Smithsonian) Washington D.C.

- These discoveries are the result of a continuing collaboration between the Natural History Museum of Utah, the National Park Service, and the Bureau of Land Management.

Excavation

- The first skeleton of Allosaurus jimmadseni was excavated during the summers of 1990 to 1994 by staff of the National Park Service's Dinosaur National Monument. The skeleton block was so heavy it required the use of explosives to remove surrounding rock and a helicopter to fly out the 2700 kg block. The head of the skeleton was missing

- The first bones of Allosaurus jimmadseni discovered included toes and some tail vertebrae. Later excavation revealed most of an articulated skeleton missing the head and part of the tail.

- The radioactive skull of the first specimen of Allosaurus jimmadseni, which had previously eluded discovery, was found in 1996 by Ramal Jones of the University of Utah using a radiation detector.

Allosaurus jimmadseni, a new species of dinosaur discovered in Utah, has a distinctive
crests that run from the eyes to the nose [Credit: Andrey Atuchin]

Preparation

- It required seven years to fully prepare all of the bones of Allosaurus jimmadseni.

- Much of the preparation was done by then Dinosaur National Monument employees Scott Madsen and Ann Elder, with some assistance from Dinosaur National Monument volunteers and students at Brigham Young University.

Other

- The Natural History Museum of Utah houses the world's largest collection of Allosaurus fossils, which are frequently studied by researchers from around the world.

- More than 270 National Park Service (NPS) areas preserve fossils even though only 16 of those were established wholly or in part for their fossils. Fossils in NPS areas can be found in the rocks or sediments of a park, in museum collections, and in cultural contexts (building stones, artifacts, historical legends, and documents).

-The United States Bureau of Land Management manages more land--247 million acres--than any other federal agency, and manages paleontological resources using scientific principles and expertise.

Source: University of Utah [January 24, 2020]

Clays in Antarctica from millions of years ago reveal past climate changes

Members of the TASMANDRAKE research group of the Andalusian Earth Sciences Institute (IACT), which pertains to the University of Granada and CSIC, have published a research paper in the prestigious international journal Scientific Reports describing their analysis of clays from Antarctica dating back 35.5 million years, to reconstruct past climate changes.

Glaucony grains observed under an electron microscope
[Credit: University of Granada]

Their study was conducted in the area known as Drake Passage—the body of water that separates South America from Antarctica, between Cape Horn (Chile) and the South Shetland Islands (Antarctica). The results help to better understand the climatic conditions prior to the formation of the Antarctic Circumpolar Current, thus evaluating possible links between the development of the ice sheet in Antarctica and the changes in the tectonic and paleoceanographic configuration. Such questions constitute key facets of past climate functioning that provide boundary conditions for today's climate models, which predict a general rise in sea levels over the coming centuries.

The article analyses the relevance as a climatic indicator of the mineral commonly known as 'glauconite', which is more properly termed 'the glauconia facies' or 'glauconia'. This is a type of green clay, formed mainly in shallow marine environments (<500 m) with temperatures below 15° C, under very specific oxygenation conditions.

The existence of this clay formation in the Antarctic region has received little scholarly attention to date compared to other geological records on the planet. The characteristic green-coloured mineral has been observed around Antarctica and the Antarctic Ocean in sedimentary sequences of the Terminal Eocene Event—that is, before one of the main climatic transitions in Earth's history. The Eocene–Oligocene climate transition took place approximately 34–33.6 million years ago.

Northwest region of the Antarctic Peninsula (South Shetland Islands)
[Credit: University of Granada]

This scientific contribution describes, for the first time in the Antarctic Ocean, a glauconitisation event (in which glauconia was formed) approximately 35.5 million years ago in the Weddell Sea, northeast of the Antarctic Peninsula between South America and Antarctica.

The formation of glauconia 35.5 million years ago marks the onset of progressive sea level rise in the north Weddell Sea during the Terminal Eocene. The results of this scientific study thus provide new insights regarding changes in paleoceanographic conditions just prior to the Eocene–Oligocene climate transition and the controversial opening and deepening of Drake Passage.

Studying the weather of the past to predict the future

The separation of the Antarctic continent from South America and Oceania allowed bodies of water to transfer freely between the Pacific and Atlantic Oceans. This new circulation of bodies of water resulted in the Circumpolar Current and, with it, the thermal insulation of the Antarctic and the formation of the ice cap on a continental scale.

Map of Antarctica showing the location of the Antarctic Circumpolar Current (ACC), which flows from west to east.
The ACC is a fundamental element in the deep global circulation connecting the Pacific, Atlantic, and Indian
Oceans. It is therefore an important part of the global ocean circulation network that distributes
 heat around the Earth [Credit: University of Granada]

The opening of Drake Passage between South America and the Antarctic Peninsula is therefore considered one of the most important events in the history of the Earth's oceanic and atmospheric circulation. However, in the absence of dating for the formation of the sedimentary basins of Drake Passage, it is difficult to specify the precise age when the Passage began to open up and the Circumpolar Current started to form. The glauconia analysis conducted by the TASMANDRAKE research group contributes to progress in this area of study.

To put these changes into perspective, Adrian Lopez Quiros, the principal author of the research, notes that "it is necessary to study the past to understand the present and help predict the future," by better understanding the tectonic, climatic, and paleoceanographic conditions that led to the onset and subsequent evolution of this important ocean current.

The United Nations' Intergovernmental Panel on Climate Change (IPCC), a major reference source for climate forecasts, established several possible future climate scenarios in 2014. However, the new data, when comparing simulations with real-world data, predict even greater impacts than those previously foreseen in the IPCC climate scenarios. Therefore, climate change is developing faster than previously thought. With its research, the TASMANDRAKE group aims to provide new variables for these models—focusing on sediments and geophysics—to ensure that its results reflect real-life events even more accurately, especially in terms of the transoceanic currents, global warming, and rising sea levels.

Source: University of Granada [January 23, 2020]

Mushrooms are older than thought

The origin and evolution of the kingdom Fungi--more commonly known as mushrooms--are still very mysterious. Only 2% of species in this kingdom have been identified, and their delicate nature means fossils are extremely rare and difficult to tell apart from other microorganisms. Until now, the oldest confirmed mushroom fossil was 460 million years old.

Fossilized network of filaments where vestiges of chitin - a very tough compound found in the cell
walls of fungi - was detected [Credit: Steeve Bonneville/Universite Libre de Bruxelles]

A group of researchers led by Professor Steeve Bonneville, from the 'Biogeochemistry and Earth system modelling' research unit (Faculty of Sciences) at the Universite libre de Bruxelles, has discovered a new mushroom fossil--the oldest to ever be identified from its molecular composition. Published in Science Advances, the study was conducted with help from several groups at ULB (Centre for Microscopy and Molecular Imaging and 4MAT), in close collaboration with Professor Liane Benning from the German Research Centre for Geoscience (GFZ Potsdam) and with support from other institutions abroad, including the UK's synchrotron (Diamond Light Source) and the Carnegie Institution for Science (Washington).

The fossilized remains of mycelium (a network of interconnected microscopic strands) were discovered in rocks whose age is between 715 and 810 million years--a time in Earth's history when life on the continents' surface was in its very infancy. These ancient rocks, found in the Democratic Republic of the Congo and part of the collection of the Africa Museum on Tervuren, formed in a lagoon or coastal lake environment. 'The presence of fungi in this transitional area between water and land leads us to believe that these microscopic mushrooms were important partners of the first plants that colonized the Earth's surface around 500 million years ago', explains Steeve Bonneville, professor at the Universite libre de Bruxelles and coordinator of the study.

Previous mushroom fossils had been identified only based on the morphology of organic remains extracted from rocks using corrosive acid compounds. 'This method damages the chemistry of organic fossils and only allows morphological analysis, which can lead to incorrect interpretations because certain morphological characteristics are common to different branches of living organisms', Steeve Bonneville says.

This is why the authors of this new study used multiple molecular analysis techniques at a microscopic scale: synchrotron radiation spectroscopy (XANES, μFTIR), μ-Raman confocal microscopy, fluorescence microscopy (CLSM) and electron microscopy (FIB-TEM-HAADF). Using these techniques, it was possible to study the chemistry of organic remains in situ, without chemical treatment. This enabled the researchers to detect traces of chitin, a very tough compound found in the cell walls of fungi. They also demonstrated that the organisms were eukaryotes, i.e. their cells had a nucleus. "Only by cross- correlating chemical and micro-spectroscopic analyses could we demonstrate that the structures found in the old rock are indeed ~ 800-million-year-old fungal remains", reacts Liane Benning from GFZ Potsdam.

'This is a major discovery, and one that prompts us to reconsider our timeline of the evolution of organisms on Earth', concludes Steeve Bonneville. 'The next step will be to look further back in time, in even more ancient rocks, for evidence of those microorganisms that are truly at the origins of the animal kingdom.'

Source: Universite libre de Bruxelles [January 22, 2020]

Warm-blooded crocs thrived in Jurassic cold snap

They are revered throughout nature as chilling predators … now research shows crocodiles have not always been the cold-blooded creatures they are today.

Metriorhynchus superciliosus [Credit: Martin Fritzlar, Flickr]

Scientists who analysed fossil teeth belonging to some of the species' ancient ancestors say at least one type of prehistoric crocodile was warm-blooded.

Body temperature

The findings suggest the animals—called metriorhynchids—could raise their body temperature to stay warm in falling temperatures in a manner similar to modern-day birds and mammals.

Researchers say this likely enabled the animals, which lived during the Jurassic and Cretaceous periods, to thrive during a spell of global cooling around 150 million years ago. Their cold-blooded cousins, by contrast, struggled to adapt but ultimately survived.

Being warm-blooded was key to metriorhynchids evolving a dolphin-like body—including flippers and a tail fin—and venturing out to live in the open oceans, the scientists say.

Fossil teeth

A team of palaeontologists, including researchers from Edinburgh, analysed the mineral make-up of teeth from metriorhynchids and a closely related family known as teleosaurids.

Oxygen levels in the fossil tooth enamel were affected by the animals' body temperature, and measuring them enabled researchers to discover whether they were cold- or warm-blooded.

Jurassic Period

Their analysis shows that metriorhynchids could raise their body temperature above that of the surroundings by using their metabolism to generate heat, meaning they were warm-blooded.

While they were less efficient at heating themselves than most other warm-blooded animals, their adaptability likely helped them survive when sea temperatures dropped at the end of the Jurassic Period.

Teleosaurids were cold-blooded, the researchers found, and kept warm in the same way as modern crocodiles—by basking in the sun. They may have struggled to stay warm when sea temperatures fell, which could partly explain why many of them died out at the end of the Jurassic Period.

"This discovery helps us better understand these bizarre crocs. They rapidly changed from animals looking similar to modern long-snouted crocodiles, to ones with flippers, a tail fin and massive, forward-facing eyes. Their transition from land to sea dwellers increasingly mirrors the better-known transformation undergone by dolphins and whales millions of years ago," says Dr. Mark Young.

The findings are published in Philosophical Transactions of the Royal Society B: Biological Sciences.

Source: University of Edinburgh [January 22, 2020]

Neutron source enables a look inside dino eggs

Did the chicks of dinosaurs from the group oviraptorid hatch from their eggs at the same time? This question can be answered by the length and arrangement of the embryo's bones, which provide information about the stage of development. But how do you look inside fossilized dinosaur eggs? Paleontologists from the University of Bonn used the neutron source of the Technical University of Munich at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching. This showed that oviraptorids developed at different speeds in their eggs and that they resemble modern birds in this respect. The results have been published in the journal Integrative Organismal Biology.

Reconstruction of a clutch of eggs with silhouettes of the oviraptorids
[Credit: Chien-Hsing Lee/Tzu-Ruei Yang/Thomas Engler]

Until now, researchers have assumed that the two-legged dinosaurs known as oviraptorids, which lived in Central Asia during the Upper Cretaceous (from 88 to 66 million years), should be placed between modern crocodiles and birds with regard to their reproductive biology. Crocodiles bury their eggs and the offspring hatch at the same time. With birds, however, hatching in the nest often happens at different times.

Together with scientists from Taiwan, Switzerland and the Heinz Maier-Leibnitz Zentrum in Garching, paleontologists from the University of Bonn have now investigated how differently the development of embryos in three 67 million years old oviraptorid egg fossils from the Ganzhou Basin of Jiangxi Province in China had progressed. "Oviraptorid eggs are found relatively frequently in Central Asia, but most of them are removed from the context of their discovery," says Thomas Engler from the Institute for Geosciences at the University of Bonn. Often it is then no longer discernible whether the eggs are from a single clutch.

Important find in China

"This is different with the fossils we've examined: We found a pair of eggs and another egg together embedded in a block of rock," reports Dr. Tzu-Ruei Yang, who discovered the unusual find during an excavation near the city of Ganzhou in China. This led the researchers to conclude that the 7-inch (18cm) eggs were laid almost at the same time by a female oviraptorid. Yang completed his doctorate at the Institute for Geosciences at the University of Bonn and now works as a researcher at the National Museum of Natural Sciences in Taiwan.

The three oviraptorid eggs studied by scientists at the University of Bonn and the TU Munich
[Credit: W. Schürmann/TU München]

The researchers tried to estimate whether the baby dinosaurs would have hatched at the same time or at different times based on the developmental stage of the embryos in the three eggs. The length of the bones in the egg plays an important role here. "The embryo with comparatively longer bones is more developed," explains Yang. Another indication is the extent to which the bones are connected to each other. A more strongly connected skeleton suggests a higher developmental stage of the dinosaur embryo.

A look inside the dinosaur egg

But how is it possible to determine the position of bones inside a fossilized dinosaur egg? The paleontologists at the University of Bonn initially tried to do this with the institute's own X-ray microcomputer tomograph. "Unfortunately, it was not possible to distinguish the bones from the surrounding rock," says Engler.

Right: Neutron tomogram as cross-section through egg 3, scanned at the ANTARES facility. Different bones can be seen
as round, lighter structures, including parts of the pelvis. A 3-D model of the surface of egg 3 can be seen on the left
[Credit: Scan created by Burkhard Schillinger/MLZ]

For this reason, the researchers took the dinosaur eggs to the research neutron source of the Technical University of Munich at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching. "The high penetration depth of the neutrons at the NECTAR and ANTARES facilities made it possible to visualize the internal structures," says Dr. Malgorzata Makowska, who was in charge of measurements and analyses at the MLZ and is now carrying out research at the Swiss neutron source PSI.

The length and position of the embryo bones led the researchers to conclude that the single egg must have been laid earlier than the pair of eggs in the same clutch. However, the embryos of the pair were also at different developmental stages. Thin sections confirm these results. The researchers used these to measure the thickness of the eggshells. The developing embryo absorbs part of the shell because it needs calcium for its growing skeleton. "The more material is removed from the egg shell, the more advanced the embryo's development," explains Yang.

Photogrammetry of egg 3:The object was photographed and reconstructed
from different perspectives [Credit: Jens Lallensack]

On the basis of these indications, the scientists conclude that the reproductive biology of oviraptorids were similar to that of modern birds, whose chicks hatch at different times. The results argue against the strategy of crocodiles or turtles, which all emerge from their eggs at the same time. This has brought the researchers one step closer to the life of the long extinct oviraptorids, who roamed Central Asia on two legs. "Furthermore, the study shows that exploring fossils with neutrons yields novel scientific results," says Engler.

Source: University of Bonn [January 22, 2020]

New research finds Earth's oldest asteroid strike linked to 'big thaw'

Curtin University scientists have discovered Earth's oldest asteroid strike occurred at Yarrabubba, in outback Western Australia, and coincided with the end of a global deep freeze known as a Snowball Earth.

The Yarrabubba Impact Structure
[Credit: Google Earth]

The research, published in the leading journal Nature Communications, used isotopic analysis of minerals to calculate the precise age of the Yarrabubba crater for the first time, putting it at 2.229 billion years old - making it 200 million years older than the next oldest impact.

Lead author Dr Timmons Erickson, from Curtin's School of Earth and Planetary Sciences and NASA's Johnson Space Center, together with a team including Professor Chris Kirkland, Associate Professor Nicholas Timms and Senior Research Fellow Dr Aaron Cavosie, all from Curtin's School of Earth and Planetary Sciences, analysed the minerals zircon and monazite that were 'shock recrystallized' by the asteroid strike, at the base of the eroded crater to determine the exact age of Yarrabubba.

The team inferred that the impact may have occurred into an ice-covered landscape, vaporised a large volume of ice into the atmosphere, and produced a 70km diameter crater in the rocks beneath.

Professor Kirkland said the timing raised the possibility that the Earth's oldest asteroid impact may have helped lift the planet out of a deep freeze.

"Yarrabubba, which sits between Sandstone and Meekatharra in central WA, had been recognised as an impact structure for many years, but its age wasn't well determined," Professor Kirkland said.

Researchers analysed 'shock crystallized' zircon to determine
the exact age of Yarrabubba [Credit: Curtin University]

"Now we know the Yarrabubba crater was made right at the end of what's commonly referred to as the early Snowball Earth - a time when the atmosphere and oceans were evolving and becoming more oxygenated and when rocks deposited on many continents recorded glacial conditions".

Associate Professor Nicholas Timms noted the precise coincidence between the Yarrabubba impact and the disappearance of glacial deposits.

"The age of the Yarrabubba impact matches the demise of a series of ancient glaciations. After the impact, glacial deposits are absent in the rock record for 400 million years. This twist of fate suggests that the large meteorite impact may have influenced global climate," Associate Professor Timms said.

"Numerical modelling further supports the connection between the effects of large impacts into ice and global climate change. Calculations indicated that an impact into an ice-covered continent could have sent half a trillion tons of water vapour - an important greenhouse gas - into the atmosphere. This finding raises the question whether this impact may have tipped the scales enough to end glacial conditions."

Dr Aaron Cavosie said the Yarrabubba study may have potentially significant implications for future impact crater discoveries.

"Our findings highlight that acquiring precise ages of known craters is important - this one sat in plain sight for nearly two decades before its significance was realised. Yarrabubba is about half the age of the Earth and it raises the question of whether all older impact craters have been eroded or if they are still out there waiting to be discovered," Dr Cavosie said.

Author: Lucien Wilkinson | Source: Curtin University [January 22, 2020]

A chronicle of giant straight-tusked elephants

About 800,000 years ago, the giant straight-tusked elephant Palaeoloxodon migrated out of Africa and became widespread across Europe and Asia.

Reconstructed life appearance of the extinct European straight-tusked elephant Palaeoloxodon antiquus
in (top) side and (bottom) frontal view, based on remains uncovered from the Neumark-Nord 1 site
 in Saxony-Anhalt, Germany [Credit: Hsu Shu-yu]

It divided into many species, with distinct types in Japan, Central Asia and Europe -- even some dwarf forms as large as a small donkey on some Mediterranean islands.

In a new study by scientists in Spain, Italy and the UK, including University of Bristol PhD student Hanwen Zhang, published in the journal, Quaternary Science Reviews, some order has been brought into our understanding of all these species.

The most intriguing feature of the straight-tusked elephant, apart from its absolutely enormous size, is the massive, headband-like crest on the skull roof which projects down the forehead. When the celebrated Victorian Scottish geologist Hugh Falconer studied the first fossil skull of Palaeoloxodon found in India, he remarked that the head seemed 'so grotesquely constructed that it looks the caricature of an elephant's head in a periwig'.

For a long time, palaeontologists thought that the European species, Palaeoloxodon antiquus, had a rather slenderly built skull roof crest; whereas the Indian species Palaeoloxodon namadicus, is characterised by an extremely robust skull crest that extends near to the base of the trunk from the top of the skull.

But some Palaeoloxodon skulls, found in Italy and Germany, with almost the same exaggerated skull crest as the Indian form, led a few experts into suspecting these might all be single species.

Hanwen Zhang, who is based in Bristol's School of Earth Sciences, said: "Just like modern elephants, Palaeoloxodon went through six sets of teeth in their lifetimes. This means we can tell the age of any individual with confidence by looking at its fossilised teeth.

"When we looked at a series of skulls from Italy, Germany and India, we found a consistent pattern: the skull crest developed from being very small, not protruding beyond the forehead in juveniles to being larger and more protruding in young adults, eventually becoming very stout in aged adults."

The study's lead author, Asier Larramendi, an independent researcher from Spain, added: "As I plotted various skull and limb bone measurements for these incredible prehistoric elephants, it became clear that the Indian Palaeoloxodon form a distinct group from the European ones; even in European skulls with quite pronounced crests, the skull roof never becomes as thickened as in the Indian specimens.

"This tells us we once had two separate species of these enormous elephants in Europe and India.

"Besides the funky skull roof crest, the head of the straight-tusked elephant is also remarkable for being huge, the largest of any elephant ever - some 4.5 feet from the top of the skull roof to the base of the tusk sheaths!

"Therefore, the skull crest probably evolved to provide additional attachment areas for extra neck muscles, so the animal did not fall on its head."

Hanwen Zhang said: "Having gotten to the bottom of the antiquus/namadicus problem, it then became apparent that other fossil skull materials found in Asia and East Africa represent distinct, possibly more evolutionarily conservative species of Palaeoloxodon.

"Even in fully mature adults with the last set of teeth in place, the skull roof crest remains comparatively unpronounced. This is the case with the earliest Palaeoloxodon from Africa, some Asian species retained this condition."

Source: University of Bristol [January 21, 2020]

The little auks that lived in the Pacific

Findings from a 700,000-year-old fossil bone indicate that a close relative of the most abundant seabird species in the North Atlantic, the modern dovekie, or 'little auk', used to thrive in the Pacific Ocean and Japan.

Current distribution of the modern dovekie across the Atlantic [Credit: Kyoto University/
Junya Watanabe & Justin Ammendolia]

Seabirds are top predators in the marine ecosystem, and their distributions are shaped by numerous environmental factors in the ocean. As such, extensive scientific inquiries have been conducted on how seabirds respond to fluctuating oceanic environments in the ecologic and geologic timescales.

"The North Pacific has been one of the most intently investigated regions, but the fossil record of seabirds in the Pleistocene Epoch, about 2.6 to 0.01 million years ago, has been scarce," explains first author Junya Watanabe of Kyoto University's School of Science. "This has led to a frustrating lack of information in this critical time period concerning the origin of modern seabird communities."

In recent years, Watanabe and his team had been investigating seabird fossils from several locations in Chiba and Tokyo prefectures, gaining new insight on the Pleistocene seabird community in the region.

The group had been successful in identifying 17 fossils representing at least 9 species of birds: three species of ducks, a loon, an albatross, a shearwater, a cormorant, an extinct penguin-like seabird called mancalline auk, and a dovekie. Most of these species can be found in the region today; however, the presence of a dovekie was completely unexpected. Watanabe explains his findings published in Journal of Vertebrate Paleontology.

"At first it confused us that the fossil didn't match any of the Pacific auks, but once we compared it with Atlantic ones, the similarity with the modern dovekie was apparent. It is not clear whether the present fossil is from the same species or a very close cousin, but we are positive it at least comes from the same lineage."

The dovekies we know today are mostly restricted to the North Atlantic and Arctic oceans, with their rare sightings in Japan considered accidental visits. Given the unlikeliness of such accidental visitors to be preserved as fossils, the new findings suggest that dovekies were once fairly common in Japan and the Pacific.

He continues, "Now the question is why dovekies are so rare in the North Pacific today, it's almost paradoxical given their abundance in the North Atlantic. That question remains unexplained, at least until recovery and investigation of further fossil materials."

Interestingly, local decline and extinction events in the past are common in many seabird groups. Deciphering possible causes of such events requires integration of knowledge from various disciplines, including paleontology, paleoclimatology, oceanography and seabird ecology. Watanabe and his team see this as a challenging but rewarding endeavour.

Source: Kyoto University [January 21, 2020]

Arctic sea ice can't 'bounce back'

A team of scientists led by the University of Exeter used the shells of quahog clams, which can live for hundreds of years, and climate models to discover how Arctic sea ice has changed over the last 1,000 years.

Quahog clams [Credit: Paul Butler]

They found sea ice coverage shifts over timescales of decades to centuries - so shrinking ice cannot be expected to return rapidly if climate change is slowed or reversed.

The study examined whether past ice changes north of Iceland were "forced" (caused by events such as volcanic eruptions and variations in the sun's output) or "unforced" (part of a natural pattern).

At least a third of past variation was found to be "forced" - showing the climate system is "very sensitive" to such driving factors, according to lead author Dr Paul Halloran, of the University of Exeter.

"There is increasing evidence that many aspects of our changing climate aren't caused by natural variation, but are instead 'forced' by certain events," he said.

"Our study shows the large effect that climate drivers can have on Arctic sea ice, even when those drivers are weak as is the case with volcanic eruptions or solar changes.

"Today, the climate driver isn't weak volcanic or solar changes - it's human activity, and we are now massively forcing the system."

Co-author of the study Professor Ian Hall, from Cardiff University, said: "Our results suggest that climate models are able to correctly reproduce the long-term pattern of sea ice change.

"This gives us increased confidence in what climate models are telling us about current and future sea ice loss."

When there is lots of sea ice, some of this drifts southwards and, by releasing fresh water, can slow the North Atlantic Ocean circulation, otherwise known as the Atlantic Meridional Overturning Circulation (AMOC).

The AMOC brings warm water from the tropics towards the Arctic, so slowing it down cools this region and allows sea ice to grow further.

So, with less ice the AMOC can bring in more warm water - a so-called "positive feedback" where climate change drives further warming and sea ice loss.

Quahog clams are thought to be the longest-living non-colonial animal on Earth, and their shells produce growth rings which can be examined to measure past environmental changes.

Dr Halloran is part of the Global Systems Institute, which brings together experts from a wide range of fields to find solutions to global challenges.

The findings are published in the journal Scientific Reports.

Source: University of Exeter [January 21, 2020]

Climate (not humans) shaped early forests of New England

A new study in the journal Nature Sustainability overturns long-held interpretations of the role humans played in shaping the American landscape before European colonization. The findings give new insight into the rationale and approaches for managing some of the most biodiverse landscapes in the eastern U.S.

Archaeologists Dianna Doucette, Deena Duranleau, and Randy Jardin conducting investigations at the Lucy Vincent Beach
 Site, Martha's Vineyard. The long-held belief that native people used fire to create a diverse landscape of woodlands,
grasslands, heathlands, and shrublands in New England has led to a widespread use of prescribed fire as a conservation
tool. Research by Oswald and colleagues indicates that these openlands actually arose following European contact,
deforestation, and agricultural expansion [Credit: Elizabeth Chilton, Binghamton University]

The study, led by archaeologists, ecologists, and paleoclimatologists at Harvard, Emerson College and elsewhere, focuses on the coast from Long Island to Cape Cod and the nearby islands of Nantucket, Martha's Vineyard, Block Island, and Naushon--areas that historically supported the greatest densities of Native people in New England and today are home to the highest concentrations of rare habitats in the region, including sandplain grasslands, heathlands, and pitch pine and scrub oak forests.

"For decades, there's been a growing popularization of the interpretation that, for millennia, Native people actively managed landscapes - clearing and burning forests, for example - to support horticulture, improve habitat for important plant and animal resources, and procure wood resources," says study co-author David Foster, Director of the Harvard Forest at Harvard University. This active management is said to have created an array of open-land habitats and enhanced regional biodiversity.

But, Foster says, the data reveal a new story. "Our data show a landscape that was dominated by intact, old-growth forests that were shaped largely by regional climate for thousands of years before European arrival."

Fires were uncommon, the study shows, and Native people foraged, hunted, and fished natural resources without actively clearing much land.

The long-held belief that native people used fire to create a diverse landscape of woodlands, grasslands,
heathlands, and shrublands in New England has led to a widespread use of prescribed fire as a
conservation tool. Research by Oswald and colleagues indicates that these openlands actually
 arose following European contact, deforestation, and agricultural expansion. These landscapes
and their critical habitats and species are best maintained through agricultural practices like
 grazing, as seen here on conservation land on the Elizabeth Islands, Massachusetts
[Credit: David Foster]

"Forest clearance and open grasslands and shrublands only appeared with widespread agriculture during the European colonial period, within the last few hundred years," says Wyatt Oswald, a professor at Emerson College and lead author of the study.

The authors say the findings transform thinking about how landscapes have been shaped in the past - and therefore how they should be managed in the future.

"Ancient Native people thrived under changing forest conditions not by intensively managing them but by adapting to them and the changing environment," notes Elizabeth Chilton, archaeologist, co-author of the study, and Dean of the Harpur College of Arts and Sciences at Binghamton University.

To reconstruct historical changes to the land, the research team combined archaeological records with more than two dozen intensive studies of vegetation, climate, and fire history spanning ten thousand years. They found that old-growth forests were predominant for millennia but are extremely uncommon today.

Conservationists have employed prescribed fire in an attempt to maintain openland habitats such
 as the Katama sandplain grassland on the island of Martha's Vineyard. Research by Oswald and
colleagues indicates that, despite a large human population for thousands of years, fire was
uncommon and landscapes across southern New England were heavily forested until
European contact and deforestation for agriculture. Grazing and other agricultural
practices can be used to maintain these uncommon habitats today
 [Credit: David Foster, Harvard University]

"Today, New England's species and habitat biodiversity are globally unique, and this research transforms our thinking and rationale for the best ways to maintain it," says Oswald. "It also points to the importance of historical research to help us interpret modern landscapes and conserve them effectively into the future."

The authors also note the unique role that colonial agriculture played in shaping landscapes and habitat. "European agriculture, especially the highly varied activity of sheep and cattle grazing, hay production, and orchard and vegetable cultivation in the 18th and 19th centuries, made it possible for open-land wildlife species and habitats that are now rare or endangered - such as the New England cottontail - to thrive," says Foster. Open-land species have declined dramatically as forests regrow on abandoned farmland, and housing and commercial development of both forests and farms have reduced their habitat.

Foster notes that the unique elements of biodiversity initiated through historical activities can be encouraged through analogous management practices today.

"Protected wildland reserves would preserve interior forest species that were abundant before European settlement," he says. "Lands managed through the diversified farming and forestry practices that created openlands and young forests during the colonial period would support another important suite of rare plants and animals."

The long-held belief that native people used fire to create a diverse landscape of woodlands, grasslands,
 heathlands, and shrublands in New England has led to a widespread use of prescribed fire as a
 conservation tool. Research by Oswald and colleagues indicates that these openlands actually
arose following European contact, deforestation, and agricultural expansion. These landscapes
 and their critical habitats and species are best maintained through agricultural practices like
grazing, as seen here on a hillside in Chilmark, Martha's Vineyard, MA.
[Credit: David Foster, Harvard University]

For successful conservation models that leverage this historical perspective, the authors point to efforts by The Trustees of Reservations, the oldest land trust in the world, which manages more than 25,000 acres in Massachusetts embracing old and young forests, farms, and many cultural resources. The organization uses livestock grazing to keep lands open for birds like bobolinks and meadowlarks, which in turn supports local farmers and produces food for local communities.

Jocelyn Forbush, Executive Vice President for the Trustees, says, "Maintaining the legacy of our conserved openlands in Massachusetts is an important goal for The Trustees and we are increasingly looking to agricultural practices to yield a range of outcomes. In particular, we are employing grazing practices to support the habitats of our open and early successional lands in addition to the scenic and cultural landscapes that shape the character of our communities."

Source: Harvard University [January 20, 2020]

New research provides evidence of strong early magnetic field around Earth

Deep within Earth, swirling liquid iron generates our planet's protective magnetic field. This magnetic field is invisible but is vital for life on Earth's surface: it shields the planet from harmful solar wind and cosmic rays from the sun.

Artist rendition of early Earth and Mars 4.2 billion years ago with internally generated magnetic fields. The long
life of the geodynamo and magnetic shielding prevented loss of the ocean on Earth, whereas the collapse of the
Martian magnetic field contributed to its loss of water [Credit: Michael Osadciw (University of Rochester,
Rochester, NY) & John A. Tarduno]

Given the importance of the magnetic field, scientists have been trying to figure out how the field has changed throughout Earth's history. That knowledge can provide clues to understanding the future evolution of Earth, as well as the evolution of other planets in the solar system.

New research from the University of Rochester provides evidence that the magnetic field that first formed around Earth was even stronger than scientists previously believed. The research, published in the Proceedings of the National Academy of Sciences, will help scientists draw conclusions about the sustainability of Earth's magnetic shield and whether or not there are other planets in the solar system with the conditions necessary to harbor life.

"This research is telling us something about the formation of a habitable planet," says John Tarduno, the William R. Kenan, Jr., Professor of Earth and Environmental Sciences and Dean of Research for Arts, Sciences, and Engineering at Rochester. "One of the questions we want to answer is why Earth evolved as it did and this gives us even more evidence that the magnetic shielding was recorded very early on the planet."

Earth's magnetic field today

Today's magnetic shield is generated in Earth's outer core. The intense heat in Earth's dense inner core causes the outer core—composed of liquid iron—to swirl and churn, generating electric currents, and driving a phenomenon called the geodynamo, which powers Earth's magnetic field. The currents in the liquid outer core are strongly affected by the heat that flows out of the solid inner core.

In order to determine the past magnetic field direction and intensity, the researchers dated and analyzed zircon crystals
collected from sites in Australia. The zircons are about two-tenths of a millimeter and contain even smaller magnetic
particles that lock in the magnetization of the earth at the time the zircons were formed. Here, a zircon crystal
is placed within the "O" on a dime, for scale [Credit: University of Rochester/John Tarduno]

Because of the location and extreme temperatures of materials in the core, scientists aren't able to directly measure the magnetic field. Fortunately, minerals that rise to Earth's surface contain tiny magnetic particles that lock in the direction and intensity of the magnetic field at the time the minerals cool from their molten state.

Using new paleomagnetic, electron microscope, geochemical, and paleointensity data, the researchers dated and analyzed zircon crystals—the oldest known terrestrial materials—collected from sites in Australia. The zircons, which are about two-tenths of a millimeter, contain even smaller magnetic particles that lock in the magnetization of the earth at the time the zircons were formed.

Earth's magnetic field 4 billion years ago

Previous research by Tarduno found that Earth's magnetic field is at least 4.2 billion years old and has existed for nearly as long as the planet. Earth's inner core, on the other hand, is a relatively recent addition: it formed only about 565 million years ago, according to research published by Tarduno and his colleagues earlier this year.

While the researchers initially believed Earth's early magnetic field had a weak intensity, the new zircon data suggests a stronger field. But, because the inner core had not yet formed, the strong field that originally developed 4 billion years ago must have been powered by a different mechanism.

"We think that mechanism is chemical precipitation of magnesium oxide within Earth," Tarduno says.

The magnesium oxide was likely dissolved by extreme heat related to the giant impact that formed Earth's moon. As the inside of Earth cooled, magnesium oxide could precipitate out, driving convection and the geodynamo. The researchers believe inner Earth eventually exhausted the magnesium oxide source to the point that the magnetic field almost completely collapsed 565 million years ago.

But the formation of the inner core provided a new source to power the geodynamo and the planetary magnetic shield Earth has today.

A magnetic field on Mars

"This early magnetic field was extremely important because it shielded the atmosphere and water removal from the early Earth when solar winds were most intense," Tarduno says. "The mechanism of field generation is almost certainly important for other bodies like other planets and exoplanets."

A leading theory, for instance, is that Mars, like Earth, had a magnetic field early on in its history. However, on Mars, the field collapsed and, unlike Earth, Mars did not generate a new one.

"Once Mars lost its magnetic shielding, it then lost its water," Tarduno says. "But we still don't know why the magnetic shielding collapsed. Early magnetic shielding is really important, but we're also interested in the sustainability of a magnetic field. This study gives us more data in trying to figure out the set of processes that maintain the magnetic shield on Earth."

Source: University of Rochester [January 20, 2020]

It was microbial mayhem in the Chicxulub crater, Curtin research suggests

New insights into how microbial life was quickly re-established following the mass extinction of the dinosaurs have been detailed for the first time by Curtin University-led research.

Impact illustration [Credit: Victor Leshyk]

The research, published in Geology, analyzed biomarkers, also known as molecular fossils, found in drill core rock samples from the center of the Chicxulub crater located in deep sea waters of the Gulf of Mexico.

The findings suggest that remains from land plants, fungi and coastal microbial mats, like modern stromatolites, were transported into the crater through wave activity during a giant tsunami in the immediate aftermath of the giant asteroid impact credited with causing the extinction of the dinosaurs, 66 million years ago.

Lead author Ph.D. candidate Bettina Schaefer, from the WA-Organic and Isotope Geochemistry Centre (WA-OIGC) in Curtin's School of Earth and Planetary Sciences, said the research study provided the first molecular evidence of many forms of photosynthetic life present in the Chicxulub crater, demonstrating how resilient microorganisms were after experiencing abnormally hostile conditions following the asteroid's impact.

"Our research shows that when the dust from the asteroid's impact settled and sunlight returned to ideal levels, there was a rapid resurgence of land plants, dinoflagellates, cyanobacteria and all forms of anaerobic photosynthetic sulfur bacteria, including those from microbial mats in the crater area," Ms Schaefer said.

John Curtin Distinguished Professor Kliti Grice, the founding director of WA-OIGC in Curtin's School of Earth and Planetary Sciences, said the research findings further suggested the phytoplankton communities in the post-impact crater basin continued to produce and evolve at a "rapid" rate.

"The development and productivity of phytoplankton was accompanied by major transitions in nutrient and oxygen supplies that shaped the recovery of microbial life. There was so much going on in such a short time frame, it really was like a post-apocalyptic microbial mayhem was happening in the Chicxulub crater."

Author: April Kleer | Source: Curtin University [January 20, 2020]