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]

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]

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]

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]

The drawbacks of the modern face of 'Homo antecessor'

A study led by the University of Bordeaux and the Dental Anthropology Group of the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), which has been published this week in the American Journal of Physical Anthropology, reveals that the species Homo antecessor, found in level TD6 of the Gran Dolina site in the Sierra de Atapuerca (Burgos), already endured the drawbacks of having insufficient space for the third molar or wisdom tooth to erupt.

Credit: CENIEH

Analysis of the maxilla ATD6-69, "the face" of Homo antecessor, using high-resolution techniques such as micro-computed tomography carried out at the CENIEH, has enabled the identification of signs matching ectopic development, that is, outside the proper location for the third molar, and the secondary impacting pf the second molar with its retention within the alveolar bone.

"Specifically, the wisdom tooth was undergoing development upon the crown of the second molar," says Laura Martín-Francés, principal author of this study.

In this study, the hypothesis of whether the ectopic molar of this individual, whose approximate age was 10 years, was due to a combination of factors such as the characteristic modern face and the large size of the teeth of this child from Atapuerca, is discussed for the first time.

This peculiarity would have led to the lack of space for the normal development of the wisdom tooth and the consequent retention of the second molar.

"While the particular evolution in this individual is unknown, the prognosis in these cases includes the development of caries, periodontitis and even cysts. Thus, we can be sure that around one million years ago, this person would have suffered from severe toothache," affirms Martín-Francés.

For the moment, evidence of this anomaly is only known from a single individual of this species, although the imminent excavation of the entire surface of level TD6 at Gran Dolina will offer new fossil remains to find out whether this circumstance was typical of Homo antecessor due to its modern face.

Source: CENIEH [January 18, 2020]

Human-caused biodiversity decline started millions of years ago

The human-caused biodiversity decline started much earlier than researchers used to believe. According to a new study published in the scientific journal Ecology Letters the process was not started by our own species but by some of our ancestors.

Dinofelis, painting by Mauricio Antón. The picture shows a saber-toothed cat Dinofelis eating
while one of our ancestors are watching. Dinofelis has been considered a predator that our
ancestors were greatly fearing. But new research suggests that it was human ancestors that
may have caused the eventual extinction of the species along with other major predators
[Credit: University of Gothenburg]

The work was done by an international team of scientists from Sweden, Switzerland and the United Kingdom.

The researchers point out in the study that the ongoing biological diversity crisis is not a new phenomenon, but represents an acceleration of a process that human ancestors began millions of years ago.

"The extinctions that we see in the fossils are often explained as the results of climatic changes but the changes in Africa within the last few million years were relative minor and our analyses show that climatic changes were not the main cause of the observed extinctions," explains Søren Faurby, researcher at Gothenburg University and the main author of the study.

"Our analyzes show that the best explanation for the extinction of carnivores in East Africa is instead that they are caused by direct competition for food with our extinct ancestors," adds Daniele Silvestro, computational biologist and co-author of the study.

Carnivores disappeared

Our ancestors have been common throughout eastern Africa for several million years and during this time there were multiple extinctions according to Lars Werdelin, co-author and expert on African fossils.

"By investigating the African fossils, we can see a drastic reduction in the number of large carnivores, a decrease that started about 4 million years ago. About the same time, our ancestors may have started using a new technology to get food called kleptoparasitism," he explains.

Kleptoparasitism means stealing recently killed animals from other predators. For example, when a lion steals a dead antelope from a cheetah.

The researchers are now proposing, based on fossil evidence, that human ancestors stole recently killed animals from other predators. This would lead to starvation of the individual animals and over time to extinction of their entire species.

"This may be the reason why most large carnivores in Africa have developed strategies to defend their prey. For example, by picking up the prey in a tree that we see leopards doing. Other carnivores have instead evolved social behavior as we see in lions, who among other things work together to defend their prey," explains Søren Faurby

Humans today affect the world and the species that live in it more than ever before.

"But this does not mean that we previously lived in harmony with nature. Monopolization of resources is a skill we and our ancestors have had for millions of years, but only now are we able to understand and change our behavior and strive for a sustainable future. 'If you are very strong, you must also be very kind'," concludes Søren Faurby and quotes Astrid Lindgrens book about Pippi Longstocking.

Source: University of Gothenburg [January 17, 2020]

Green in tooth and claw

Hard plant foods may have made up a larger part of early human ancestors' diet than currently presumed, according to a new experimental study of modern tooth enamel from Washington University in St. Louis.

Five skull replicas of human ancestors from left to right: A. africanus, A. afarensis, H. erectus,
H. neanderthalensis and H. sapiens sapiens [Credit: Shutterstock]

Scientists often look at microscopic damage to teeth to infer what an animal was eating. This new research -- using experiments looking at microscopic interactions between food particles and enamel -- demonstrates that even the hardest plant tissues scarcely wear down primate teeth. The results have implications for reconstructing diet, and potentially for our interpretation of the fossil record of human evolution, researchers said.

"We found that hard plant tissues such as the shells of nuts and seeds barely influence microwear textures on teeth," said Adam van Casteren, lecturer in biological anthropology in Arts & Sciences, the first author of the new study in Scientific Reports. David S. Strait, professor of physical anthropology, is a co-author.

Traditionally, eating hard foods is thought to damage teeth by producing microscopic pits. "But if teeth don't demonstrate elaborate pits and scars, this doesn't necessarily rule out the consumption of hard food items," van Casteren said.

Humans diverged from non-human apes about seven million years ago in Africa. The new study addresses an ongoing debate surrounding what some early human ancestors, the australopiths, were eating. These hominin species had very large teeth and jaws, and likely huge chewing muscles.

"All these morphological attributes seem to indicate they had the ability to produce large bite forces, and therefore likely chomped down on a diet of hard or bulky food items such as nuts, seeds or underground resources like tubers," van Casteren said.

But most fossil australopith teeth don't show the kind of microscopic wear that would be expected in this scenario.

The researchers decided to test it out.

Previous mechanical experiments had shown how grit -- literally, pieces of quartz rock -- produces deep scratches on flat tooth surfaces, using a device that mimicked the microscopic interactions of particles on teeth. But there was little to no experimental data on what happens to tooth enamel when it comes in contact with actual woody plant material.

For this study, the researchers attached tiny pieces of seed shells to a probe that they dragged across enamel from a Bornean orangutan molar tooth.

They made 16 "slides" representing contacts between the enamel and three different seed shells from woody plants that are part of modern primate diets. The researchers dragged the seeds against enamel at forces comparable to any chewing action.

The seed fragments made no large pits, scratches or fractures in the enamel, the researchers found. There were a few shallow grooves, but the scientists saw nothing that indicated that hard plant tissues could contribute meaningfully to dental microwear. The seed fragments themselves, however, showed signs of degradation from being rubbed against the enamel.

This information is useful for anthropologists who are left with only fossils to try to reconstruct ancient diets.

"Our approach is not to look for correlations between the types of microscopic marks on teeth and foods being eaten -- but instead to understand the underlying mechanics of how these scars on tooth surface are formed," van Casteren said. "If we can fathom these fundamental concepts, we can generate more accurate pictures of what fossil hominins were eating."

So those big australopith jaws could have been put to use chewing on large amounts of seeds -- without scarring teeth.

"And that makes perfect sense in terms of the shape of their teeth" said Peter Lucas, a co-author at the Smithsonian Tropical Research Institute, "because the blunt low-cusped form of their molars are ideal for that purpose."

"When consuming many very small hard seeds, large bite forces are likely to be required to mill all the grains," van Casteren said. "In the light of our new findings, it is plausible that small, hard objects like grass seeds or sedge nutlets were a dietary resource for early hominins."

Source: Washington University in St. Louis [January 17, 2020]