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Prehistoric ‘sea dragon’ discovered on English Channel Coast is identified as new species

Illustration of Thalassodraco etchesi. Credit: Megan Jacobs
Illustration of Thalassodraco etchesi. Credit: Megan Jacobs

A mysterious small marine reptile dating from 150 million years ago has been identified as a new species that may have been capable of diving very deeply. The well-preserved specimen was found in a Late Jurassic deep marine deposit along the English Channel coastline in Dorset, England.

The aquatic reptile has been determined to be part of the group known as ichthyosaurs, which were streamlined marine predators from the Late Jurassic period, according to paleontologist Megan L. Jacobs, a Baylor University doctoral candidate in geosciences and co-author of a study published in the journal PLOS ONE.

“This ichthyosaur has several differences that makes it unique enough to be its own genus and species,” Jacobs said. “New Late Jurassic ichthyosaurs in the United Kingdom are extremely rare, as these creatures have been studied for 200 years. We knew it was new almost instantly, but it took about a year to make thorough comparisons with all other Late Jurassic ichthyosaurs to make certain our instincts were correct. It was very exciting to not be able to find a match.”

The specimen, estimated to have been about 6 feet long, was discovered in 2009 by fossil collector Steve Etches MBE after a cliff crumbled along the seaside. He found it encased in a slab that would originally have been buried 300 feet deep in a limestone seafloor layer. The specimen since has been housed in The Etches Collection Museum of Jurassic Marine Life in Kimmeridge, Dorset. Jacobs named it Thalassodraco etchesi, meaning “Etches sea dragon” after Etches.

“Now that the new sea dragon has been officially named, it’s time to investigate its biology,” said study co-author David Martill, Ph.D., professor of paleontology at the University of Portsmouth in Portsmouth, United Kingdom. “There are a number of things that make this animal special.”

Investigating the Differences

“This animal was obviously doing something different compared to other ichthyosaurs. One idea is that it could be a deep diving species, like sperm whales,” Jacobs said. “The extremely deep rib cage may have allowed for larger lungs for holding their breath for extended periods, or it may mean that the internal organs weren’t crushed under the pressure. It also has incredibly large eyes, which means it could see well in low light. That could mean it was diving deep down, where there was no light, or it may have been nocturnal.”

With the deep rib cage, the creature would have looked very barrel-like, she said. Given its comparatively small flippers, it may have swum with a distinctive style from other ichthyosaurs.

The specimen’s hundreds of tiny teeth would have been suited for a diet of squid and small fish, and “the teeth are unique by being completely smooth,” Jacobs said. “All other ichthyosaurs have larger teeth with prominent striated ridges on them, so we knew pretty much straight away this animal was different.”

Changes Through History

Ichthyosaurs originated as lizard-like creatures living on land and slowly evolved into the dolphin/shark-like creature found as fossils. Their limbs evolved into flippers, most of them very long or wide.

“They still had to breathe air at the surface and didn’t have scales,” Jacobs said. “There is hardly anything actually known about the biology of these animals. We can only make assumptions from the fossils we have, but there’s nothing like it around today. Eventually, to adapt to being fully aquatic, they no longer could go up onto land to lay eggs, so they evolved into bearing live young, tail first. There have been skeletons found with babies within the mother and also ones that were actually being born.”

Thalassodraco etchesi is closely related to Nannopterygius, a widespread genus of ichthyosaurs which inhabited Late Jurassic seas across Europe, Russia and the Arctic around 248 million years ago before becoming extinct around 90 million years ago. The largest ichthyosaurs, found in North America, had skulls nearly 16 feet long.

Jacobs said that the new specimen likely died from old age or attack by predators, then sank to the seafloor.

“The seafloor at the time would have been incredibly soft, even soupy, which allowed it to nose-dive into the mud and be half buried,” she said. “The back end didn’t sink into the mud, so it was left exposed to decay and scavengers, which came along and ate the tail end. Being encased in that limestone layer allowed for exceptional preservation, including some preserved internal organs and ossified ligaments of the vertebral column.”

“It’s excellent that new species of ichthyosaurs are still being discovered, which shows just how diverse these incredible animals were,” Martill said.

Note: The above post is reprinted from materials provided by Baylor University.

Paleontologists find pterosaur precursors that fill a gap in early evolutionary history

A partial skeleton of Lagerpeton (hips, leg, and vertebrae) from ~235 million years from Argentina. Further examination of this specimen helped tie features of lagerpetids to pterosaurs. Photo courtesy of Sterling Nesbitt. Credit: Virginia Tech
A partial skeleton of Lagerpeton (hips, leg, and vertebrae) from ~235 million years from Argentina. Further examination of this specimen helped tie features of lagerpetids to pterosaurs. Photo courtesy of Sterling Nesbitt. Credit: Virginia Tech

Here’s the original story of flight. Sorry, Wright Brothers, but this story began way before your time — during the Age of the Dinosaurs.

Pterosaurs were the earliest reptiles to evolve powered flight, dominating the skies for 150 million years before their imminent extinction some 66 million years ago.

However, key details of their evolutionary origin and how they gained their ability to fly have remained a mystery; one that paleontologists have been trying to crack for the past 200 years. In order to learn more about their evolution and fill in a few gaps in the fossil record, it is imperative that their closest relatives are identified.

With the help of newly discovered skulls and skeletons that were unearthed in North America, Brazil, Argentina, and Madagascar in recent years, Virginia Tech researchers Sterling Nesbitt and Michelle Stocker from the Department of Geosciences in the College of Science have demonstrated that a group of “dinosaur precursors,” called lagerpetids, are the closest relatives of pterosaurs.

“Where did pterosaurs come from?’ is one of the most outstanding questions in reptile evolution; we think we now have an answer,” said Sterling Nesbitt, who is an associate professor of geosciences and an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center.

Their findings were published in Nature.

Fossils of Dromomeron gregorii, a species of lagerpetid, were first collected in Texas in the 1930s and 1940s, but they weren’t properly identified until 2009. Unique to this excavation was a well-preserved partial skull and braincase, which, after further investigation, revealed that these reptiles had a good sense of equilibrium and were likely agile animals.

After finding more lagerpetid species in South America, paleontologists were able to create a pretty good picture of what the lagerpetids were; which were small, wingless reptiles that lived across Pangea during much of the Triassic Period, from 237 to 210 million years ago.

And in the past 15 years, five research groups from six different countries and three continents have come together to right some wrongs in the evolutionary history of the pterosaur, after the recent discovery of many lagerpetid skulls, forelimbs, and vertebrae from the United States, Brazil, Argentina, and Madagascar.

You may be asking yourself, what gave paleontologists the idea to take a closer look at lagerpetids as the closest relatives of pterosaurs? Well, paleontologists have been studying the bones of lagerpetids for quite some time, and they have noted that the length and shape of their bones were similar to the bones of pterosaurs and dinosaurs. But with the few fossils that they had before, it could only be assumed that lagerpetids were a bit closer to dinosaurs.

What really caused a shift in the family tree can be attributed to the recently collected lagerpetid skulls and forelimbs, which displayed features that were more similar to pterosaurs than dinosaurs. And with the help of new technological advances, researchers found that pterosaurs and lagerpetids share far more similarities than meet the eye.

Using micro-computed tomographic (?CT) scanning to reconstruct their brains and sensory systems within the recently discovered skulls, paleontologists determined that the brains and sensory systems of lagerpetids had many similarities with those of pterosaurs.

“CT data has been revolutionary for paleontology,” said Stocker, who is an assistant professor of vertebrate paleontology and an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center.

“Some of these delicate fossils were collected nearly 80 years ago, and rather than destructively cutting into this first known skull of Dromomeron, we were able to use this technology to carefully reconstruct the brain and inner ear anatomy of these small fossils to help determine the early relatives of pterosaurs.”

One stark and mystifying finding was that the flightless lagerpetids had already evolved some of the neuroanatomical features that allowed the pterosaurs to fly, which brought forth even more information on the origin of flight.

“This study is a result of an international effort applying both traditional and cutting-edge techniques,” said Martín D. Ezcurra, lead author of the study from the Museo Argentino de Ciencias Naturales in Buenos Aires, Argentina. “This is an example of how modern science and collaboration can shed light on long-standing questions that haunted paleontologists during more than a century.”

Ultimately, the study will help bridge the anatomical and evolutionary gaps that exist between pterosaurs and other reptiles. The new evolutionary relationships that have emerged from this study will create a new paradigm, providing a completely new framework for the study of the origin of these reptiles and their flight capabilities.

With the little information that paleontologists had about early pterosaurs, they had often attributed extremely fast evolution for the acquisition of their unique body plan. But now that lagerpetids are deemed the precursors of pterosaurs, paleontologists can say that pterosaurs evolved at the same rate as other major reptile groups, thanks to the newly discovered “middle man.”

“Flight is such a fascinating behaviour, and it evolved multiple times during Earth’s history,” said Serjoscha W. Evers, of the University of Fribourg. “Proposing a new hypothesis of their relationships with other extinct animals is a major step forward in understanding the origins of pterosaur flight.”

Some questions still remain in this evolutionary mystery. Now that lagerpetids are the closest relatives of pterosaurs, why are they still lacking some of the key characteristics of pterosaurs, including the most outstanding of those — wings?

“We are still missing lots of information about the earliest pterosaurs, and we still don’t know how their skeletons transformed into an animal that was capable of flight,” said Nesbitt.

Nesbitt, Stocker, and a team of Virginia Tech graduate and undergraduate students will continue to study animals that appeared in the Triassic Period — a period of time in Earth history when many familiar groups of vertebrates, such as dinosaurs, turtles, mammal relatives, and amphibians, first appeared. If and when conditions are safe, they plan on going into the field to collect more fossils from the Triassic Period.

Maybe soon, we will have more information to put some finishing touches on the original story of flight.

Reference:
Martín D. Ezcurra, Sterling J. Nesbitt, Mario Bronzati, Fabio Marco Dalla Vecchia, Federico L. Agnolin, Roger B. J. Benson, Federico Brissón Egli, Sergio F. Cabreira, Serjoscha W. Evers, Adriel R. Gentil, Randall B. Irmis, Agustín G. Martinelli, Fernando E. Novas, Lúcio Roberto da Silva, Nathan D. Smith, Michelle R. Stocker, Alan H. Turner, Max C. Langer. Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria. Nature, 2020; DOI: 10.1038/s41586-020-3011-4

Note: The above post is reprinted from materials provided by Virginia Tech. Original written by Kendall Daniels and Steven Mackay.

Archaeopteryx fossil provides insights into the origins of flight

Remnants of feather sheaths on the wings of the fossil bird Archaeopteryx, shows the earliest evidence of a complex moulting strategy. The white arrows indicate the feather sheaths. Scale bar is 1 cm. Credit: Kaye et al. 2020.
Remnants of feather sheaths on the wings of the fossil bird Archaeopteryx, shows the earliest evidence of a complex moulting strategy. The white arrows indicate the feather sheaths. Scale bar is 1 cm. Credit: Kaye et al. 2020.

Flying birds moult their feathers when they are old and worn because they inhibit flight performance, and the moult strategy is typically a sequential molt. Moulting is thought to be unorganised in the first feathered dinosaurs because they had yet to evolve flight, so determining how moulting evolved can lead to better understanding of flight origins.

However, evidence of the transition to modern moulting strategies is scarce in the fossil record. Recently, Research Assistant Professor Dr Michael PITTMAN from the Research Division for Earth and Planetary Science, as well as Vertebrate Palaeontology Laboratory, at the Faculty of Science of the University of Hong Kong (HKU), Thomas G KAYE of the Foundation for Scientific Advancement (Arizona, USA) and William R WAHL of the Wyoming Dinosaur Center (Wyoming, USA), jointly discovered the earliest record of feather moulting from the famous early fossil bird Archaeopteryx found in southern Germany in rocks that used to be tropical lagoons ~150 million years ago. The findings were published in Communications Biology.

Archaeopteryx moulting strategy used to preserve maximum flight performance

The most common moult strategy in modern birds is a sequential moult, where feathers are lost from both wings at the same time in a symmetrical pattern. The sequence of feather loss follows two different strategies: The first strategy is a numerically sequential molt where feathers are lost in numerical order and is the most common among passerines birds, also known as songbirds and perching birds; the second strategy is a centre-out strategy where a centre feather is lost first, and then subsequent feathers are shed outwards from this centre point; this is more common in non-passerine birds such as falcons. This strategy minimises the size of the aerodynamic hole in the wing, which allows falcons to better maintain their flight performance during the moult for hunting.

Laser-Stimulated Fluorescence imaging co-developed at HKU revealed feather sheaths on the Thermopolis specimen of Archaeopteryx that are otherwise invisible under white light. “We found feather sheaths mirrored on both wings. These sheaths are separated by one feather and are not in numerical sequential order. This indicates that Archaeopteryx used a sequential centre-out moulting strategy, which is used in living falcons to preserve maximum flight performance,” said Kaye. This strategy was therefore already present at the earliest origins of flight.

“The centre-out moulting strategy existed in early flyers and would have been a very welcome benefit because of their otherwise poor flight capabilities. They would have appreciated any flight advantage they could obtain,” said Pittman. “This discovery provides important insights into how and when birds refined their early flight capabilities before the appearance of iconic but later flight-related adaptations like a keeled breastbone (sternum), fused tail tip (pygostyle) and the triosseal canal of the shoulder,” added Pittman.

This study is part of a larger long-term project by Pittman and Kaye and their team of collaborators to better understand the origins of flight (see notes).

Reference:
Thomas G. Kaye, Michael Pittman, William R. Wahl. Archaeopteryx feather sheaths reveal sequential center-out flight-related molting strategy. Communications Biology, 2020; 3 (1) DOI: 10.1038/s42003-020-01467-2

Note: The above post is reprinted from materials provided by The University of Hong Kong.

Rainbow Cave, Hormuz Island, Iran

Rainbow Cave, Hormuz Island, Iran
Rainbow Cave, Hormuz Island, Iran

Hormuz Island

Hormuz Island has an area of 42 km2 (16 sq mi). It is covered by sedimentary rock and layers of volcanic material on its surface. The highest point of the island is about 186 metres (610 ft) above sea level. Due to a lack of precipitation, the soil and water are salty.

Hormuz Island is a salt dome situated in the Persian Gulf waters near the mouth of Hormuz Strait in Hormuzgan province, at 8 kilometers distance from Bandar Abbas. The island is elliptical, and its rock is mostly of the igneous and often volcanic type. Hormuz is one of the most beautiful Islands of the Persian Gulf due to its geological phenomena and related landforms. This island is a mature salt diapir with great mineralogical and lithological diversity. In this research, we focused on fieldwork, which included data gathering and taking photographs and also a review of the published papers and books.

The main geotourism attractions of the island include various landforms resulted from differential erosion, as well as very attractive geomorphologic structures such as rocky and sandy beaches, sea caves, colorful salt domes, coral reefs, etc. Besides the geological and geomorphological sites of the region, the ancient and cultural features are also potential attractions for tourism development on the island.

The rocks show that, over thousands of years that the island of Hormuz gradually comes out of the water, the wear and tear on it makes different shapes. According to researches, geological age of the Hormuz island is about 600 million years ago and its life when coming out of the water is about 50 thousand years.

Rainbow Cave

This cave is created by the flow of water to the sea and its passage under the salt mountain. The depth of the cave is about 30 to 40 meters. In some parts of the cave, several corridors can be seen, which, according to geologists, have caused these corridors. The height of the roof varies along the cave and in some parts you need to bend your head to cross

Inside the cave, sedimentary and salt rocks are stacked layer by layer, creating a smooth surface just like a rainbow. The most beautiful part of the cave is the end where the colors reach their peak. The color spectrum seen in this cave is about seventy spectrums

The colors in this cave are due to their mineral composition. These compounds are metals such as iron that combine with other elements to form colored minerals. Salt rocks can be seen at the beginning of the cave, but gradually colors and colorful stones appear on the cave walls

Crystals may help reveal hidden Kilauea Volcano behavior

A lava fountain during the 1959 eruption of Kilauea Iki. Credit: USGS
A lava fountain during the 1959 eruption of Kilauea Iki. Credit: USGS

Scientists striving to understand how and when volcanoes might erupt face a challenge: many of the processes take place deep underground in lava tubes churning with dangerous molten Earth. Upon eruption, any subterranean markers that could have offered clues leading up to a blast are often destroyed.

But by leveraging observations of tiny crystals of the mineral olivine formed during a violent eruption that took place in Hawaii more than half a century ago, Stanford University researchers have found a way to test computer models of magma flow, which they say could reveal fresh insights about past eruptions and possibly help predict future ones.

“We can actually infer quantitative attributes of the flow prior to eruption from this crystal data and learn about the processes that led to the eruption without drilling into the volcano,” said Jenny Suckale, an assistant professor of geophysics at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). “That to me is the Holy Grail in volcanology.”

The millimeter-sized crystals were discovered entombed in lava after the 1959 eruption of Kilauea Volcano in Hawaii. An analysis of the crystals revealed they were oriented in an odd, but surprisingly consistent pattern, which the Stanford researchers hypothesized was formed by a wave within the subsurface magma that affected the direction of the crystals in the flow. They simulated this physical process for the first time in a study published in Science Advances Dec. 4.

“I always had the suspicion that these crystals are way more interesting and important than we give them credit for,” said Suckale, who is senior author on the study.

Detective work

It was a chance encounter that prompted Suckale to act upon her suspicion. She had an insight while listening to a Stanford graduate student’s presentation about microplastics in the ocean, where waves can cause non-spherical particles to assume a consistent misorientation pattern. Suckale recruited the speaker, then-Ph.D. student Michelle DiBenedetto, to see if the theory could be applied to the odd crystal orientations from Kilauea.

“This is the result of the detective work of appreciating the detail as the most important piece of evidence,” Suckale said.

Along with Zhipeng Qin, a research scientist in geophysics, the team analyzed crystals from scoria, a dark, porous rock that forms upon the cooling of magma containing dissolved gases. When a volcano erupts, the liquid magma—known as lava once it reaches the surface—is shocked by the cooler atmospheric temperature, quickly entrapping the naturally occurring olivine crystals and bubbles. The process happens so rapidly that the crystals cannot grow, effectively capturing what happened during eruption.

The new simulation is based on crystal orientations from Kilauea Iki, a pit crater next to the main summit caldera of Kilauea Volcano. It provides a baseline for understanding the flow of Kilauea’s conduit, the tubular passage through which hot magma below ground rises to the Earth’s surface. Because the scoria can be blown several hundred feet away from the volcano, these samples are relatively easy to collect. “It’s exciting that we can use these really small-scale processes to understand this huge system,” said DiBenedetto, the lead author of the study, now a postdoctoral scholar at the Woods Hole Oceanographic Institution.

Catching a wave

In order to remain liquid, the material within a volcano needs to be constantly moving. The team’s analysis indicates the odd alignment of the crystals was caused by magma moving in two directions at once, with one flow directly atop the other, rather than pouring through the conduit in one steady stream. Researchers had previously speculated this could happen, but a lack of direct access to the molten conduit barred conclusive evidence, according to Suckale.

“This data is important for advancing our future research about these hazards because if I can measure the wave, I can constrain the magma flow—and these crystals allow me to get at that wave,” Suckale said.

Monitoring Kilauea from a hazard perspective is an ongoing challenge because of the active volcano’s unpredictable eruptions. Instead of leaking lava continuously, it has periodic bursts resulting in lava flows that endanger residents on the southeast side of the Big Island of Hawaii.

Tracking crystal misorientation throughout the different stages of future Kilauea eruptions could enable scientists to deduce conduit flow conditions over time, the researchers say.

“No one knows when the next episode is going to start or how bad it’s going to be—and that all hinges on the details of the conduit dynamics,” Suckale said.

Reference:
“Crystal aggregates record the pre-eruptive flow field in the volcanic conduit at Kilauea, Hawaii” Science Advances (2020). DOI: 10.1126/sciadv.abd4850

Note: The above post is reprinted from materials provided by Stanford University.

Seismic activity of New Zealand’s alpine fault more complex than suspected

Looking at the Toaroha River, near New Zealand’s Alpine Fault. | GNS Science
Looking at the Toaroha River, near New Zealand’s Alpine Fault. | GNS Science

A rupture along the full length of the fast-slipping Alpine Fault on New Zealand’s South Island poses the largest potential seismic threat to the southern and central parts of the country. But new evidence of a 19th century earthquake indicates that in at least one portion of the fault, smaller earthquakes may occur in between such large rupture events.

The findings published in the Bulletin of the Seismological Society of America suggest that some places along the fault, particularly around the towns of Hokitika and Greymouth, could experience strong ground shaking from Alpine fault earthquakes more often than previously thought.

The best paleoseismic evidence to date suggests the southern and central sections of the Alpine Fault, at the boundary separating the Australian and Pacific tectonic plates, typically rupture during very large full-section earthquakes of magnitude 7.7 or larger. The last such earthquake took place in 1717.

After trenching along the fault at the Staples site near the Toaroha River, however, Robert Langridge of GNS Science and colleagues uncovered evidence of a more recent earthquake along the northeastern end of the fault’s central portion. Radiocarbon dating places this earthquake between 1813 and 1848.

“One of the real challenges with the Alpine Fault — because it is so bush-covered — is actually finding sites that have been cleared and therefore can be studied,” said Langridge. “Once we started working there [at the Staples site] the story really grew in large part because of the richness of dateable organic material in the trenches.”

The four most recent earthquakes uncovered by the researchers at the site range in dates from 1084 to 1848. The events were confirmed by data collected from other nearby trenching sites and from geological deposits called turbidites, which are sediments shaken loose into a body of water by seismic activity, in lakes along the central section of the Alpine fault.

The most recent earthquake could represent a “partial-section” rupture of only the central portion of the Alpine fault, a rupture of the fault’s northern section that continued southwest into the central segment, or even triggered slip from a rupture along the nearby Marlborough Fault System. Langridge and colleagues said that there isn’t enough evidence yet to favor one of these scenarios over the others.

However, the findings do suggest that seismic activity on the Alpine Fault is more complex than suspected, particularly along its northern reaches where the plate boundary transitions into another fault zone.

“One of the outcomes of this study is that you should expect a shorter recurrence interval of strong shaking at fault section ends,” Langridge said. “Because of the recurrence times of earthquakes though, you obviously have to wait a long time to see the effects of such fault behavior.”

“That’s why paleoseismology is a vital tool in understanding faults,” he added, “because otherwise we’d have only short insights into the past.”

The Alpine Fault is sometimes compared with California’s San Andreas Fault, being another fast-moving strike slip fault near a plate boundary. Langridge said researchers in California and New Zealand have a long history of earthquake science collaboration and are learning from each other about the treatment of active faults and fault segmentation for seismic hazard models.

“The San Andreas Fault, being on the opposite side of the Pacific plate, it is like our distant brother or whanau — family,” said Langridge.

Reference:
Robert M. Langridge, Pilar Villamor, Jamie D. Howarth, William F. Ries, Kate J. Clark, Nicola J. Litchfield. Reconciling an Early Nineteenth-Century Rupture of the Alpine Fault at a Section End, Toaroha River, Westland, New Zealand. Bulletin of the Seismological Society of America, 2020; DOI: 10.1785/0120200116

Note: The above post is reprinted from materials provided by Seismological Society of America.

Continents prone to destruction in their infancy, study finds

The quantitative model used in the study explains the enigmatic melt degrees and layered structures observed in most cratons on Earth.
The quantitative model used in the study explains the enigmatic melt degrees and layered structures observed in most cratons on Earth.

Monash University geologists have shed new light on the early history of the Earth through their discovery that continents were weak and prone to destruction in their infancy.

Their research, which relies on mathematical modelling, is published today in Nature.

The Earth is our home and over its 4,500,000,000 (4.5 billion) year history has evolved to form the environment we live in and the resources on which we depend.

However, the early history of Earth, covering its first 1.5 billion years remains almost unknown and, consequently, poorly understood.

“This was the time of formation of the first continents, the emergence of land, the development of the early atmosphere, and the appearance of primordial life — all of which are the result of the dynamics of our planet’s interiors,” said lead study author ARC Future Fellow Dr Fabio Capitanio from the Monash University School of Earth, Atmosphere and Environment.

“Reproducing the conditions of the early Earth in computer-generated numerical models, we show that the release of internal primordial heat, three to four times that of the present-day, caused large melting in the shallow mantle, which was then extruded as magma (molten rock) onto the Earth’s surface,” he said.

According to the researchers, the shallow mantle left behind by this process was dehydrated and rigid and formed the keels of the first continents.

“Our results explain that continents remained weak and prone to destruction in their infancy, ~4.5 to ~4.0 billion years ago, and then progressively differentiated and became rigid over the next billion years to form the core of our modern continents,” Dr Capitanio said.

“The emergence of these rigid early continents resulted in their weathering and erosion, changing the composition of the atmosphere and providing nutrients to the ocean seeding the development of life.”

Dr Capitanio specialises in investigating the dynamics of the Earth’s tectonics and plate motions to better understand the mechanisms that force single plates or whole-Earth changes.

The work adds to the knowledge on supercontinent formation and its fragmentation into the present-day continents.

The quantitative model used in the study explains the enigmatic melt degrees and layered structures observed in most cratons on Earth.

The process shows that continents remain weak and prone to destruction in their infancy, then progressively melt and differentiate to become stable continents.

This accounts for the transition from the Hadean, covering the first 500 million years of Earth history, in which crust was completely recycled, to the Archean (four to three billion years ago), when rigid continental keels built up and remain preserved through time.

“The geological record suggests that the very early continents did not survive and were recycled in the planet’s interiors, yet this trend dramatically inverted approximately four billion years ago, when the most enduring piece of continents, cratons, appeared,” Dr Capitanio said.

Only tiny crystals remain from Earth’s earliest continental crust, formed more than 4 billion years ago. The mysterious disappearance of this crust can now be explained. The very process that formed new crust, replacing the old one, is critically related to how the continents became stable. By extracting melt from the Earth’s interior, rigid rafts in the mantle form beneath the new crust, shielding it from further destruction. The crust formed in this way is still preserved in the core of today’s continents, the cratons.

The cratons keep record of early life on our planet and are currently a very small fraction of the surface.

Australia hosts three cratons, the Yilgarn, the Pilbara, and the Gawler cratons.

Reference:
Fabio A. Capitanio, Oliver Nebel, Peter A. Cawood. Thermochemical lithosphere differentiation and the origin of cratonic mantle. Nature, 2020; 588 (7836): 89 DOI: 10.1038/s41586-020-2976-3

Note: The above post is reprinted from materials provided by Monash University.

Researchers discover 16 million-year-old bat fossil

Representative Image: Holotype of Onychonycteris finneyi
Representative Image: Holotype of Onychonycteris finneyi

A new species of bat that is 16 million years old has been discovered by an international group that includes University of Valencia lecturers Francisco J. Ruiz Sánchez and Plini Montoya. The finding was made at the palaeontologic site of Mas d’Antolino B, in the town of l’Alcora, and corresponds to the lower Miocene in the Valencia region in Spain.

The identification has been completed thanks to the study of isolated teeth. The study has been published in Earth and Environmental Science Transactions of the Royal Society of Edinburgh.

As well as the two lecturers from the University of Valencia, who belong to the Department of Botany and Geology, the team was comprised by paleontologists Vicente D. Crespo (University of Valencia graduate), the Museo de la Plata museum (Argentina) and Paloma Sevilla, from the Complutense University of Madrid.

The research refers to a set of fossil bat remains from several sites in the town of Alcora (Castellón province), specifically near the Araia d’Alcora village. These fossils, obtained within the framework of digs authorized and funded by the regional Culture Council, have revealed some surprising data that is of great scientific interest. For example, a new species has been identified, and secondly, the finding of a new genus that had heretofore not been discovered in fossil form, which represents a true Lazarus taxon (which means a taxon of which there is no fossil records for a lengthy period of time).

Furthermore, the group of fossil bats represented a typically tropical association, closer to a prior geological period.

At the palaeontological site of Mas d’Antonio B, known since 2008, numerous species of shrews, squirrels, hamsters, dormice, crocodiles and other animals have been found. These animals, framed in an environment that would resemble today’s tropical forest, date back to over 16 million years ago, at the beginning of the era known as Miocene, specifically the “age of mammals” called Aragonian.

The new bat species has been “baptized” with the scientific name Cuvierimops penalveri, in honor of paleontologist Enrique Peñalver, former lecturer at the University of Valencia and recently recognized as one of the best international scientists for his work on fossil insects, and who also carried out studies in the same area where these new findings have taken place.

The new species belongs to the current family of bats called free-tailed or molosid, but curiously belongs to a genus that was thought to have gone extinct ten million years earlier. Said family was predominant in Europe during the Oligocene period, around 23-33 million years ago, but in the early Miocene it had whittled down to a small number of species, and today it is represented by a single species. This is why it is surprising that, of the ten bats discovered at Araia d’Alcora, five are from species that belong to said family of molosids.

Also noteworthy within the recovered collection is a representative of the Chaerephon, whose sole fossils found to date were only 10,000 years old, which gives this discovery the category of Lazarus taxon. Other important bats found at Araia d’Alcora are the molosid Rhizomops, which is the first time it has appeared in the lower Miocene, and the vespertilionid Submyotodon, found for the first time in a palaeontologic site in the Iberian Peninsula.

In this era, the environment in Araia corresponded to a tropical forest, with meadows that would have been located around a large lake that takes up most of the current towns of l’Alcora, Ribesalbes and Fanzara. The tropical environment of the area during the lower Miocene is confirmed by the abundance of molosid bats, which today are common in tropical climate areas, such as Center and South America, Ethiopia, India or Australia.

Obtaining the fossil remains of small mammals required a thorough process of cleaning-sieving of several tons of sediment, as well as grading the abundant waste obtained at the end of the process. Studying the fossil teeth was done using several techniques, including electronic microscopy.

Note: The above post is reprinted from materials provided by Asociacion RUVID.

Incredible vision in ancient marine creatures drove an evolutionary arms race

An artist's reconstruction of 'Anomalocaris' briggsi swimming within the twilight zone. Credit: Katrina Kenny
An artist’s reconstruction of ‘Anomalocaris’ briggsi swimming within the twilight zone. Credit: Katrina Kenny

Ancient deep sea creatures called radiodonts had incredible vision that likely drove an evolutionary arms race according to new research published today.

The international study, led by Professor John Paterson from the University of New England’s Palaeoscience Research Center, in collaboration with the University of Adelaide, the South Australian Museum and The Natural History Museum (UK), found that radiodonts developed sophisticated eyes over 500 million years ago, with some adapted to the dim light of deep water.

“Our study provides critical new information about the evolution of the earliest marine animal ecosystems,” Professor Paterson said. “In particular, it supports the idea that vision played a crucial role during the Cambrian Explosion, a pivotal phase in history when most major animal groups first appeared during a rapid burst of evolution over half a billion years ago.”

Radiodonts, meaning “radiating teeth”, are a group of arthropods that dominated the oceans around 500 million years ago. The many species share a similar body layout comprising of a head with a pair of large, segmented appendages for capturing prey, a circular mouth with serrated teeth, and a squid-like body. It now seems likely that some lived at depths down to 1000 meters and had developed large, complex eyes to compensate for the lack of light in this extreme environment.

“When complex visual systems arose, animals could better sense their surroundings,” Professor Paterson explained. “That may have fuelled an evolutionary arms race between predators and prey. Once established, vision became a driving force in evolution and helped shape the biodiversity and ecological interactions we see today.”

Some of the first radiodont fossils discovered over a century ago were isolated body parts, and initial attempts at reconstructions resulted in “Frankenstein’s monsters”.

But over the past few decades many new discoveries—including whole radiodont bodies—have given a clearer picture of their anatomy, diversity and possible lifestyles.

Co-author, Associate Professor Diego García-Bellido from the University of Adelaide and South Australian Museum, said the rich treasure trove of fossils at Emu Bay Shale on South Australia’s Kangaroo Island in particular has helped to build a clearer picture of Earth’s earliest animals.

“The Emu Bay Shale is the only place in the world that preserves eyes with lenses of Cambrian radiodonts. The more than thirty specimens of eyes we now have, has shed new light on the ecology, behavior and evolution of these, the largest animals alive half-a-billion years ago,” A/Prof. García-Bellido said.

In 2011, the team published two papers in the journal Nature on fossil compound eyes from the 513-million-year-old Emu Bay Shale on Kangaroo Island.

The first paper on this subject documented isolated eye specimens of up to one centimeter in diameter, but the team were unable to assign them to a known arthropod species. The second paper reported the stalked eyes of Anomalocaris, a top predator up to one meter in length, in great detail.

“Our new study identifies the owner of the eyes from our first 2011 paper: ‘Anomalocaris’ briggsi —representing a new genus that is yet to be formally named,” Prof. Paterson said.

“We discovered much larger specimens of these eyes of up to four centimeters in diameter that possess a distinctive ‘acute zone’, which is a region of enlarged lenses in the center of the eye’s surface that enhances light capture and resolution.”

The large lenses of ‘Anomalocaris’ briggsi suggest that it could see in very dim light at depth, similar to amphipod crustaceans, a type of prawn-like creature that exists today. The frilly spines on its appendages filtered plankton that it detected by looking upwards.

Dr. Greg Edgecombe, a researcher at The Natural History Museum, London and co-author of the study, added that the South Australian radiodonts show the different feeding strategies previously indicated by the appendages—either for capturing or filtering prey—are paralleled by differences in the eyes.

“The predator has the eyes attached to the head on stalks but the filter feeder has them at the surface of the head. The more we learn about these animals the more diverse their body plan and ecology is turning out to be,” Dr. Edgecombe said.

“The new samples also show how the eyes changed as the animal grew. The lenses formed at the margin of the eyes, growing bigger and increasing in numbers in large specimens—just as in many living arthropods. The way compound eyes grow has been consistent for more than 500 million years.”

Reference:
John R. Paterson et al, Disparate compound eyes of Cambrian radiodonts reveal their developmental growth mode and diverse visual ecology, Science Advances (2020). DOI: 10.1126/sciadv.abc6721

Note: The above post is reprinted from materials provided by University of Adelaide.

A New Species of Rare Phylum Loricifera Discovered in the Deep-sea Surrounding Japan

New loriciferan from Japan: Wataloricus japonicus Credit: Shinta Fujimoto
New loriciferan from Japan: Wataloricus japonicus
Credit: Shinta Fujimoto

The Loricifera is a microscopic, sediment-dwelling marine invertebrate, with a head covered in over 200 spines and an abdomen with a protective shell – known as a lorica. Since it was first discovered in 1983, just under 40 species have been written about. Now, that number is one more thanks to a group of scientists who reported on a new genus and species of Loricifera.

Their findings were published in the Journal Marine Biodiversity.

Loricifera typically inhabit the space between sand and mud particles in the ocean. Fossils exist from the Cambrian period, suggesting a long existence on Earth. They have complicated life cycles and a few species are reported to live in anoxic environments. Their exact position on the animal tree of life is unknown.

Researchers from Tohoku University, Kyushu University, Mie University, Hiroshima University and the University of Copenhagen reported on a new species of Loricifera inhabiting Japan’s area from the continental slope to the deeper sea – roughly 177 m to 1059 m below the sea. This marks the second time a new Loricifera species has been found near Japan; the last one was discovered in 1988 in the Izu-Ogasawara Trench.

Fujimoto and his team hope to uncover as much as they can about this rare species. “Each new species provides us with answers, but also more questions. We will keep on looking for these extraordinary animals to understand the species’ diversity, ecology, life history and evolution.”

Note: The above post is reprinted from materials provided by Asia Research News.

Geoscientists use zircon to trace origin of Earth’s continents

Igneous zircon crystal: shows zircon had two main growth periods approx. 20 million years apart in different magmas.
Cathodoluminescence image from a scanning electron microscope of a typical igneous zircon crystal from samples studied by the QUT research team, revealing growth rings of the zircon. Yellow circles enclose ablation sites by a laser from which isotopic data is measured to determine the age of zircon growth. The analytical spots here show this zircon had two main growth periods approximately 20 million years apart in different magmas. Credit: QUT

Geoscientists have long known that some parts of the continents formed in the Earth’s deep past, but the speed in which land rose above global seas — and the exact shapes that land masses formed — have so far eluded experts.

But now, through analyzing roughly 600,000 mineral analyses from a database of about 7,700 different rock samples, a team led by Jesse Reimink, assistant professor of geosciences at Penn State, thinks they’re getting closer to the answers.

The researchers say that Earth’s land masses began to slowly rise above sea level about 3 billion years ago. When their interpretation is combined with previous work, including work from other Penn State researchers, it suggests that continents took roughly 500 million years to rise to their modern heights, according to findings recently published in Earth and Planetary Science Letters.

To reach this conclusion, scientists applied a unique statistical analysis to crystallization ages from the mineral zircon, which is reliably dateable and is frequently found in sedimentary rocks. While these researchers did not date these samples, the samples were all dated using the the uranium-lead decay system. This method measures the amount of lead in a sample and calculates from the well established rate of uranium decay, the age of the crystal. When zirconium forms, no lead is incorporated into its structure, so any lead is from uranium decay.

The minerals found in the sedimentary rock samples originally formed in older magmas but, through erosion and transport, traveled in rivers and were eventually deposited in the ocean where they were turned into sedimentary rock beneath the surface of the sea floor. The ages of zircons retrieved from individual rock samples can be used to tell the type of continent they were eroded from.

The ages of zircons from Eastern North American rocks are, for instance, different from those of land masses such as Japan, which was formed by much more recent volcanic activity.

“If you look at the Mississippi River, it’s eroding rocks and zircons from all over North America. It’s gathering mineral grains that have a massive age range from as young as a million years to as old as a few billions of years,” Reimink said. “Our analysis suggests that as soon as sediment started to be formed on Earth they were formed from sedimentary basins with a similarly large age range.”

Sediments are formed from weathering of older rocks, and carry the signature of past landmass in time capsules such as zircons. The research doesn’t uncover the overall size of primordial continents, but it does speculate that modern-scale watersheds were formed as early as 2.7 billion years ago.

“Our research matches nicely with the preserved rock record,” Reimink said.

This finding is critical for a few reasons. First, knowing when and how the continents formed advances research on the carbon cycle in the land, water and atmosphere. Secondly, it gives us clues as to the early origins of Earth. That could prove useful as we discover more about life and the formation of other planets. Earth is a life-sustaining planet, in part, because of how continental crust influences our atmospheric and oceanic composition. Knowing how and when these processes occurred could hold clues to the creation of life.

“Whenever we’re able to determine processes that led to our existence, it relates to the really profound questions such as: Are we unique? Is Earth unique in the universe? And are there other Earths out there,” Reimink said. “These findings help lead us down the path to the answers we need about Earth that allow us to compare our planet to others.”

The Natural Sciences and Engineering Research Council of Canada partially supported this work.

Reference:
Jesse Ray Reimink, Joshua H.F.L. Davies, Alessandro Ielpi. Global zircon analysis records a gradual rise of continental crust throughout the Neoarchean. Earth and Planetary Science Letters, 2020; 116654 DOI: 10.1016/j.epsl.2020.116654

Note: The above post is reprinted from materials provided by Penn State. Original written by David Kubarek.

What will the climate be like when Earth’s next supercontinent forms?

Distribution of snow and ice in winter and summer on Aurica (left) and Amasia. Credit: Way et al. 2020
Distribution of snow and ice in winter and summer on Aurica (left) and Amasia. Credit: Way et al. 2020

Long ago, all the continents were crammed together into one large land mass called Pangea. Pangea broke apart about 200 million years ago, its pieces drifting away on the tectonic plates — but not permanently. The continents will reunite again in the deep future. And a new study, presented today during an online poster session at the meeting of the American Geophysical Union, suggests that the future arrangement of this supercontinent could dramatically impact the habitability and climate stability of Earth. The findings also have implications for searching for life on other planets.

The study, which has been submitted for publication, is the first to model the climate on a supercontinent in the deep future.

Scientists aren’t exactly sure what the next supercontinent will look like or where it will be located. One possibility is that, 200 million years from now, all the continents except Antarctica could join together around the north pole, forming the supercontinent “Amasia.” Another possibility is that “Aurica” could form from all the continents coming together around the equator in about 250 million years.

In the new study, researchers used a 3D global climate model to simulate how these two land mass arrangements would affect the global climate system. The research was led by Michael Way, a physicist at the NASA Goddard Institute for Space Studies, an affiliate of Columbia University’s Earth Institute.

The team found that, by changing atmospheric and ocean circulation, Amasia and Aurica would have profoundly different effects on the climate. The planet could end up being 3 degrees Celsius warmer if the continents all converge around the equator in the Aurica scenario.

In the Amasia scenario, with the land amassed around both poles, the lack of land in between disrupts the ocean conveyor belt that currently carries heat from the equator to the poles. As a result, the poles would be colder and covered in ice all year long. And all of that ice would reflect heat out into space.

With Amasia, “you get a lot more snowfall,” explained Way. “You get ice sheets, and you get this very effective ice-albedo feedback, which tends to lower the temperature of the planet.”

In addition to cooler temperatures, Way suggested that sea level would probably be lower in the Amasia scenario, with more water tied up in the ice caps, and that the snowy conditions could mean that there wouldn’t be much land available for growing crops.

Aurica, by contrast, would probably be a bit beachier, he said. The land concentrated closer to the equator would absorb the stronger sunlight there, and there would be no polar ice caps to reflect heat out of Earth’s atmosphere — hence the higher global temperature.

Although Way likens Aurica’s shores to the paradisiacal beaches of Brazil, “the inland would probably be quite dry,” he warned. Whether or not much of the land would be farmable would depend on the distribution of lakes and what types of precipitation patterns it experiences — details that the current paper doesn’t delve into, but could be investigated in the future.

The simulations showed that temperatures were right for liquid water to exist on about 60% of Amasia’s land, as opposed to 99.8% of Aurica’s — a finding that could inform the search for life on other planets. One of the main factors that astronomers look for when scoping out potentially habitable worlds is whether or not liquid water could survive on the planet’s surface. When modeling these other worlds, they tend to simulate planets that are either completely covered in oceans, or else whose terrain looks like that of modern-day Earth. The new study, however, shows that it’s important to consider land mass arrangements while estimating whether temperatures fall in the ‘habitable’ zone between freezing and boiling.

Although it may be 10 or more years before scientists can ascertain the actual land and sea distribution on planets in other star systems, the researchers hope that having a larger library of land and sea arrangements for climate modeling could prove useful in estimating the potential habitability of neighboring worlds.

Hannah Davies and Joao Duarte from the University of Lisbon, and Mattias Green from Bangor University in Wales were co-authors on this research.

Note: The above post is reprinted from materials provided by Earth Institute at Columbia University. Original written by Sarah Fecht.

Only dinosaurs found in ireland described for the first time

Illustration of the Jurassic thyreophoran Scelidosaurus harrisonii, Jack Mayer Wood, CC BY-SA 4.0, via Wikimedia Commons
Illustration of the Jurassic thyreophoran Scelidosaurus harrisonii, Jack Mayer Wood, CC BY-SA 4.0, via Wikimedia Commons

The only dinosaur bones ever found on the island of Ireland have been formally confirmed for the first time by a team of experts from the University of Portsmouth and Queen’s University Belfast, led by Dr Mike Simms, a curator and palaeontologist at National Museums NI.

The two fossil bones were found by the late Roger Byrne, a schoolteacher and fossil collector, who donated them along with many other fossils to Ulster Museum. Analysis has confirmed they are from early Jurassic rocks found in Islandmagee, on the east coast of County Antrim.

Ulster Museum has announced plans to put them on display when it reopens after the latest rounds of restrictions are lifted.

Dr Simms, National Museums NI, said: “This is a hugely significant discovery. The great rarity of such fossils here is because most of Ireland’s rocks are the wrong age for dinosaurs, either too old or too young, making it nearly impossible to confirm dinosaurs existed on these shores. The two dinosaur fossils that Roger Byrne found were perhaps swept out to sea, alive or dead, sinking to the Jurassic seabed where they were buried and fossilised.”

The article, published in the Proceedings of the Geologists’ Association, is part of a larger project to document Jurassic rocks in Northern Ireland and draws on many fossils in Ulster Museum’s collections.

Originally it was assumed the fossils were from the same animal, but the team were surprised to discover that they were from two completely different dinosaurs. The study, employing the latest available technology, identified the type of dinosaur from which each came. One is part of a femur (upper leg bone) of a four-legged plant-eater called Scelidosaurus. The other is part of the tibia (lower leg bone) of a two-legged meat-eater similar to Sarcosaurus.

The University of Portsmouth team, researcher Robert Smyth, originally from Ballymoney, and Professor David Martill, used high-resolution 3D digital models of the fossils, produced by Dr Patrick Collins of Queen’s University Belfast, in their analysis of the bone fragments.

Robert Smyth said: “Analysing the shape and internal structure of the bones, we realised that they belonged to two very different animals. One is very dense and robust, typical of an armoured plant-eater. The other is slender, with thin bone walls and characteristics found only in fast-moving two-legged predatory dinosaurs called theropods.”

“Despite being fragmentary, these fossils provide valuable insight on a very important period in dinosaur evolution, about 200 million years ago. It’s at this time that dinosaurs really start to dominate the world’s terrestrial ecosystems.”

Professor Martill said: “Scelidosaurus keeps on turning up in marine strata, and I am beginning to think that it may have been a coastal animal, perhaps even eating seaweed like marine iguanas do today.”

To find out when the fossils will go on display at the Ulster Museum follow @ulstermuseum on Twitter, @ulstermuseumbelfast on Facebook and @ulstermuseum on Instagram.

Reference:
Michael J. Simms, Robert S.H. Smyth, David M. Martill, Patrick C. Collins, Roger Byrne. First dinosaur remains from Ireland. Proceedings of the Geologists’ Association, 2020; DOI: 10.1016/j.pgeola.2020.06.005

Note: The above post is reprinted from materials provided by University of Portsmouth.

New trilobite fossil reveals cephalic specialization of trilobites in Middle Cambrian

Nearly complete exoskeleton (left) and cranidium (right) of Phantaspisauritus gen. et sp. nov. Credit: NIGPAS
Nearly complete exoskeleton (left) and cranidium (right) of Phantaspisauritus gen. et sp. nov. Credit: NIGPAS

Trilobites achieved their maximum genetic diversity in the Cambrian. However, unlike this diversity measure, the morphological disparity of trilobites based on cranidial outline reached the peak in the Middle to Late Ordovician.

Early to middle Cambrian trilobites with a specialized cephalon are rare, especially among the ptychoparioids. Even with a few exceptions, ptychoparioids exhibit a monotonous pattern of head specialization, characterized by additional cephalic border spines.

Recently, led by Prof. Zhao Fangchen, postgraduate Sun Zhixin and Dr. Zeng Han from the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences (NIGPAS) described a ptychopariid trilobite with an unusual cephalic morphology named Phantaspis auritus gen. et sp. nov. from the middle Cambrian Mantou Formation in Shandong Province, North China.

This unique trilobite provides new insights into the morphological range and structural foundation of the cephalic specialization in Cambrian trilobites. The study was published in Acta Palaeontologica Polonica.

Phantaspis is characterized by a cephalon with an extended anterior area of double-lobate shape resembling a pair of rabbit ears in later ontogenetic stages, which represents a form of specialization in a Cambrian trilobite that was not repeated in any younger trilobites. This illustrates the diversity of Cambrian trilobites in morphotypes and provides an example of ptychoparioid cranidial outline variation during the middle Cambrian caused by specialization.

The extended cephalon of Phantaspis is reminiscent of certain sediment feeders with a specialized cephalon, for example species of Harpina and Trinucleidae. However, in Phantaspis the anterior border was not thickened as those of the above groups. Other than adaptation to a particular life habit, further possibilities should be considered.

The cephalicshape seen in Phantaspis may have reduced the risk of predation by increasing their effective size, thus making it harder for predators to eat them, similar to other trilobites.

In addition, the development and stabilization of cranidial morphology associated with sexual maturity suggest a possibility of sexual selection, similar to ‘beetle’-like horns known from other trilobites, which are assumed to reflect this type of selective strategy.

Reference:
Sun et al., A new middle Cambrian trilobite with a specialized cephalon from Shandong Province, North China. Acta Palaeontologica Polonica(2020). DOI: 10.4202/app.00753.2020

Note: The above post is reprinted from materials provided by Chinese Academy of Sciences.

Palaeontologists describe a preservation process unique to resins

Amber piece from the site of San Just with dinosaur feather remains. Credits: S. Álvarez Parra et al. Scientific Reports
Amber piece from the site of San Just with dinosaur feather remains. Credits: S. Álvarez Parra et al. Scientific Reports

A team of paleontologists described two amber pieces found in sites in Teruel (Spain) with remains from vertebrates corresponding to the Early Cretaceous. Both pieces have their origins in the same conservation process of resins, described for the first time by the researchers. One of these remains corresponds to the finding of the oldest mammalian hair in amber worldwide, and the remains found in the other piece correspond to dinosaur feathers.

The team, whose results have been published in the journal Scientific Reports, is formed by SergioÁlvarez Parra and Xavier Delclòs, both from the University of Barcelona; Mónica M. Solórzano Kraemer, from the Senckenberg Natural History Museum (Frankfurt, Germany); Luis Alcalá, from Dinópolis (Teruel), and Enrique Peñalver, from the Geological and Minning Institute of Spain (Valencia).

The origin of both pieces is in the resin formed about 105 and 110 million years ago, corresponding to the Early Cretaceous. The cretaceous sites of amber are abundant in the Iberian Peninsula, and its study has provided many findings of global relevance. In particular, Teruel province has many of these sites.

Dinosaur feathers and mammalian hair

One of the pieces was found years ago in the amber site in Sant Just, in Utrillas, and another in Ariñi, in the Santa María mine, both in Teruel. The piece from Sant Just includes remains of dinosaur feathers distributed in the convex surface of amber with a stalactite shape.

The amber from Ariño presents three mammalian hairs with its characteristic microscopic scale pattern, exceptionally preserved. The parallel disposition of the three hairs and their similar proportions allow researchers to identify it as a small lock from a mammal and it corresponds to the oldest finding of hair in amber. “The determination of both findings is very complex, but it is likely for the feather remains to correspond to the extinct birds Enantiornithes, like other feathers in amber. Regarding the lock of hair, we should consider that the surface scale pattern is similar to the current mammalian hair,” notes Sergio Álvarez, researcher at the UB and first author of the study. “Ariño was already known for its vertebrate fossils, such as the dinosaurs Proa valdearinnoensis and Europelta carbonensis, but no-one thought we could find remains from vertebrates included in amber,” adds Álvarez.

A new conservation process for resin

In the study, the researchers described for the first time a process they call “pull off vestiture,” through which small portions of the feather and fur of a living being are trapped after being in contact with a sticky mass of resin, the necessary amount of time for it to harden.

The dinosaur and the mammal to which the feathers and the lock of hair correspond, respectively, from the studied amber pieces taht were in contact with resin while they were resting or sleeping in or near a tree. Later, with movement, these epidermal structures were torn off. When the resin hardens, the entire structures are removed, but the closer portions are not covered by the resin and are not preserved.

A similar but not identical process has been observed in sticky traps that three of the researchers installed on resin trees in Madagascar. These traps also retained hairs from mammals that touched them although, due to their high stickiness, they quickly ripped them off at minimal contact. “The feature of the process described in this research is that a somewhat long time must pass between the animal’s contact with the resin and the pulling off of the vestiture,” points out Xavier Delclòs, professor at the Faculty of Earth Sciences and member of the Biodiversity Research Institute (IRBio) of the UB. “Thus, the findings of this study and the new process shed light on the complexity of ecosystems during the Cretaceous,” concludes the researcher.

Both amber pieces in the study are in the Palaeontological Museum of Aragon (Fundación Conjunto Paleontológico de Teruel—Dinópolis) and both add more value to the large palaeontological heritage of the province of Teruel.

Reference:
Sergio Álvarez-Parra et al. Cretaceous amniote integuments recorded through a taphonomic process unique to resins, Scientific Reports (2020). DOI: 10.1038/s41598-020-76830-8

Note: The above post is reprinted from materials provided by University of Barcelona.

Piecing together the Alaska coastline’s fractured volcanic activity

Schematic diagram showing the geometry of a typical subduction zone and the production of arc volcanoes. Credit: Xiaotao Yang
Schematic diagram showing the geometry of a typical subduction zone and the production of arc volcanoes. Credit: Xiaotao Yang

Among seismologists, the geology of Alaska’s earthquake– and volcano-rich coast from the Aleutian Islands to the southeast is fascinating, but not well understood. Now, with more sophisticated tools than before, a University of Massachusetts Amherst team reports unexpected new details about the area’s tectonic plates and their relationships to volcanoes.

Plate tectonics — the constant underground movement of continental and ocean shelves, is often characterized by “subduction zones” where plates clash, one usually sliding under another. Many are prime earthquake- and volcano-prone regions.

Lead author Xiaotao Yang says, “For a long time, the whole central Alaska region was thought to have one simple subduction plate. What we discovered is that there are actually two major subduction slabs. It’s a surprise that we see differences between these two slabs and the associate mantle materials.” Overall, Yang says the new research shows, “there are many more subtleties and variations that we had not seen before.”

Yang, who did this work at UMass Amherst with co-author Haiying Gao, is now on the faculty at Purdue University. Writing in the Journal of Geophysical Research: Solid Earth, they point out that central Alaska is “an ideal place to investigate subduction segmentation and its correlation with volcano distribution” because “it is not clearly understood what controls the distribution of arc volcanoes.”

Yang says their study highlights how complex a subduction zone can be and how this complexity may control volcano distribution. It also helps to clarify a long-standing question in seismology: what determines whether volcanoes are present and whether they are in a linear arc, or in clusters. Yang says it depends in part on whether rocks deep in the mantle above the subducting slab melt into magma, and how magma is stored in the crust.

For their investigations, Yang and Gao used a powerful seismic imaging technique that Yang says is similar to a medical CAT scan of the Earth. With it, they constructed a detailed seismic velocity model of the Aleutian-Alaska margin from crust to the uppermost mantle. Seismic velocity refers to the rate at which a seismic wave travels through a material such as magma or crust. Waves travel more slowly through low-density, low-velocity material compared to surrounding rocks, for example, he says.

The researchers’ new model reveals multiple downgoing slabs, with various seismic velocities, thicknesses and dip angles, they write. Yang adds, “Once we got to look at the two central Alaska volcanoes for the first time in a really precise way, what we see is a much more complicated subduction system than we knew before. This new information about the complexity helps us to understand the distribution of volcanoes in Alaska. It’s all more complicated than the tools could show us before,” he adds.

Their findings help to explain why there is a break in the arc of volcanoes called the Denali Volcanic Gap, Yang says. Below it is a wedge-shaped region of high seismic velocity material above the subduction plate but below the mantle. It is relatively cold and dry with no melting, which explains why there is no volcano in the region.

By contrast, the cluster of volcanoes in the Wrangell Volcanic Field do not have the same signature, he adds. The Wrangell volcanoes have distinctly low seismic velocity material in the crust. It’s a rather large magma reservoir that may explain why they’re in a cluster instead of an arc, Yang says, though “the fact that it’s there helps to explain where the magma came from for past eruptions.”

This study was made possible by the National Science Foundation’s (NSF) array of seismic sensors in Alaska, part of its EarthScope Transportable Array program, Yang notes. His co-author Gao had startup funding from UMass Amherst and an NSF CAREER grant. They also used computational resources at the Massachusetts Green High Performance Computing Center in Holyoke.

Yang says that their work adds to seismologists’ understanding of volcano distribution in the Cascades in the Pacific Northwest, South America and the south Pacific. He hopes to follow up with more detailed analyses of magma reservoirs in the crust, how volcanoes are fed and particularly, whether Aleutian volcanoes have magma in the crust.

Reference:
Xiaotao Yang, Haiying Gao. Segmentation of the Aleutian‐Alaska Subduction Zone Revealed by Full‐Wave Ambient Noise Tomography: Implications for the Along‐Strike Variation of Volcanism. Journal of Geophysical Research: Solid Earth, 2020; 125 (11) DOI: 10.1029/2020JB019677

Note: The above post is reprinted from materials provided by University of Massachusetts Amherst.

Prehistoric shark hid its largest teeth

With mouths closed, the older, smaller teeth of the ancestors of today’s sharks stood upright on the jaw, while the younger and larger teeth pointed towards the tongue and were thus invisible when the mouth was closed. Credit: Christian Klug, UZH
With mouths closed, the older, smaller teeth of the ancestors of today’s sharks stood upright on the jaw, while the younger and larger teeth pointed towards the tongue and were thus invisible when the mouth was closed. Credit: Christian Klug, UZH

Some, if not all, early sharks that lived 300 to 400 million years ago not only dropped their lower jaws downward but rotated them outwards when opening their mouths. This enabled them to make the best of their largest, sharpest and inward-facing teeth when catching prey, paleontologists at the Universities of Zurich and Chicago have now shown using CT scanning and 3D printing.

Many modern sharks have row upon row of formidable sharp teeth that constantly regrow and can easily be seen if their mouths are just slightly opened. But this was not always the case. The teeth in the ancestors of today’s cartilaginous fish (chondrichthyan), which include sharks, rays and chimaeras, were replaced more slowly. With mouths closed, the older, smaller and worn out teeth of sharks stood upright on the jaw, while the younger and larger teeth pointed towards the tongue and were thus invisible when the mouth was closed.

Jaw reconstruction thanks to computed tomography

Paleontologists at the University of Zurich, the University of Chicago and the Naturalis Biodiversity Center in Leiden (Netherlands) have now examined the structure and function of this peculiar jaw construction based on a 370-million-year-old chondrichthyan from Morocco. Using computed tomography scans, the researchers were able not only to reconstruct the jaw, but also print it out as a 3D model. This enabled them to simulate and test the jaw’s mechanics.

What they discovered in the process was that unlike in humans, the two sides of the lower jaw were not fused in the middle. This enabled the animals to not only drop the jaw halves downward but at the same automatically rotate both outwards. “Through this rotation, the younger, larger and sharper teeth, which usually pointed toward the inside of the mouth, were brought into an upright position. This made it easier for animals to impale their prey,” explains first author Linda Frey. “Through an inward rotation, the teeth then pushed the prey deeper into the buccal space when the jaws closed.”

Jaw joint widespread in the Paleozoic era

This mechanism not only made sure the larger, inward-facing teeth were used, but also enabled the animals to engage in what is known as suction-feeding. “In combination with the outward movement, the opening of the jaws causes sea water to rush into the oral cavity, while closing them results in a mechanical pull that entraps and immobilizes the prey.”

Since cartilaginous skeletons are barely mineralized and generally not that well preserved as fossils, this jaw construction has evaded researchers for a long time. “The excellently preserved fossil we’ve examined is a unique specimen,” says UZH paleontologist and last author Christian Klug. He and his team believe that the described type of jaw joint played an important role in the Paleozoic era. With increasingly frequent tooth replacement, however, it became obsolete over time and was replaced by the often peculiar and more complex jaws of modern-day sharks and rays.

Reference:
Linda Frey, Michael I. Coates, Kristen Tietjen, Martin Rücklin, Christian Klug. A symmoriiform from the Late Devonian of Morocco demonstrates a derived jaw function in ancient chondrichthyans. Communications Biology, 2020; 3 (1) DOI: 10.1038/s42003-020-01394-2

Note: The above post is reprinted from materials provided by University of Zurich.

Former piece of Pacific Ocean floor imaged deep beneath China

A graphic showing the convective heat cycle (red arrows) that drives plate tectonic motion (black arrows) on Earth. Heat flows toward subduction zones through the uppermost mantle layer, the asthenosphere. A computer model from Rice University finds that the asthenosphere can locally drag plates along with it rather than acting exclusively as a brake on plate movements as had been widely believed. (Image courtesy of Surachit/Wikimedia Commons)
A graphic showing the convective heat cycle (red arrows) that drives plate tectonic motion (black arrows) on Earth. Heat flows toward subduction zones through the uppermost mantle layer, the asthenosphere. A computer model from Rice University finds that the asthenosphere can locally drag plates along with it rather than acting exclusively as a brake on plate movements as had been widely believed. (Image courtesy of Surachit/Wikimedia Commons)

In a study that gives new meaning to the term “rock bottom,” seismic researchers have discovered the underside of a rocky slab of Earth’s surface layer, or lithosphere, that has been pulled more than 400 miles beneath northeastern China by the process of tectonic subduction.

The study, published by a team of Chinese and U.S. researchers in Nature Geoscience, offers news evidence about what happens to water-rich oceanic tectonic plates as they are drawn through Earth’s mantle beneath continents.

Rice University seismologist Fenglin Niu, a co-corresponding author, said the study provides the first high-resolution seismic images of the top and bottom boundaries of a rocky, or lithospheric, tectonic plate within a key region known as the mantle transition zone, which starts about 254 miles (410 kilometers) below Earth’s surface and extends to about 410 miles (660 kilometers).

“A lot of studies suggest that the slab actually deforms a lot in the mantle transition zone, that it becomes soft, so it’s easily deformed,” Niu said. How much the slab deforms or retains its shape is important for explaining whether and how it mixes with the mantle and what kind of cooling effect it has.

Earth’s mantle convects like heat in an oven. Heat from Earth’s core rises through the mantle at the center of oceans, where tectonic plates form. From there, heat flows through the mantle, cooling as it moves toward continents, where it drops back toward the core to collect more heat, rise and complete the convective circle.

Previous studies have probed the boundaries of subducting slabs in the mantle, but few have looked deeper than 125 miles (200 kilometers) and none with the resolution of the current study, which used more than 67,000 measurements collected from 313 regional seismic stations in northeastern China. That work, which was done in collaboration with the China Earthquake Administration, was led by co-corresponding author Qi-Fu Chen from the Chinese Academy of Sciences.

The research probes fundamental questions about the processes that shaped Earth’s surface over billions of years. Mantle convection drives the movements of Earth’s tectonic plates, rigid interlocked pieces of Earth’s surface that are in constant motion as they float atop the asthenosphere, the topmost mantle layer and the most fluid part of the inner planet.

Where tectonic plates meet, they jostle and grind together, releasing seismic energy. In extreme cases, this can cause destructive earthquakes and tsunamis, but most seismic motion is too faint for humans to feel without instruments. Using seismometers, scientists can measure the magnitude and location of seismic disturbances. And because seismic waves speed up in some kinds of rock and slow in others, scientists can use them to create images of Earth’s interior, in much the same way a doctor might use ultrasound to image what’s inside a patient.

Niu, a professor of Earth, environmental and planetary sciences at Rice, has been at the forefront of seismic imaging for more than two decades. When he did his Ph.D. training in Japan more than 20 years ago, researchers were using dense networks of seismic stations to gather some of the first detailed images of the submerged slab boundaries of the Pacific plate, the same plate that was imaged in study published this week.

“Japan is located about where the Pacific plate reaches around 100-kilometer depths,” Niu said. “There is a lot of water in this slab, and it produces a lot of partial melt. That produces arc volcanoes that helped create Japan. But, we are still debating whether this water is totally released in that depth. There is increasing evidence that a portion of the water stays inside the plate to go much, much deeper.”

Northeastern China offers one of the best vantage points to investigate whether this is true. The region is about 1,000 kilometers from the Japan trench where the Pacific plate begins its plunge back into the planet’s interior. In 2009, with funding from the National Science Foundation and others, Niu and scientists from the University of Texas at Austin, the China Earthquake Administration, the Earthquake Research Institute of Tokyo University and the Research Center for Prediction of Earthquakes and Volcanic Eruptions at Japan’s Tohoku University began installing broadband seismometers in the region.

“We put 140 stations there, and of course the more stations the better for resolution,” Niu said. “The Chinese Academy of Sciences put additional stations so they can get a finer, more detailed image.”

In the new study, data from the stations revealed both the upper and lower boundaries of the Pacific plate, dipping down at a 25-degree angle within the mantle transition zone. The placement within this zone is important for the study of mantle convection because the transition zone lies below the asthenosphere, at depths where increased pressure causes specific mantle minerals to undergo dramatic phase changes. These phases of the minerals behave very differently in seismic profiles, just as liquid water and solid ice behave very different even though they are made of identical molecules. Because phase changes in the mantle transition zone happen at specific pressures and temperatures, geoscientists can use them like a thermometer to measure the temperature in the mantle.

Niu said the fact that both the top and bottom of the slab are visible is evidence that the slab hasn’t completely mixed with the surrounding mantle. He said heat signatures of partially melted portions of the mantle beneath the slab also provide indirect evidence that the slab transported some of its water into the transition zone.

“The problem is explaining how these hot materials can be dropped into the deeper part of the mantle,” Niu said. “It’s still a question. Because they are hot, they are buoyant.”

That buoyancy should act like a life preserver, pushing upward on the underside of the sinking slab. Niu said the answer to this question could be that holes have appeared in the deforming slab, allowing the hot melt to rise while the slab sinks.

“If you have a hole, the melt will come out,” he said. “That’s why we think the slab can go deeper.”

Holes could also explain the appearance of volcanos like the Changbaishan on the border between China and North Korea.

“It’s 1,000 kilometers away from the plate boundary,” Niu said. “We don’t really understand the mechanism of this kind of volcano. But melt rising from holes in the slab could be a possible explanation.”

Reference:
Xin Wang, Qi-Fu Chen, Fenglin Niu, Shengji Wei, Jieyuan Ning, Juan Li, Weijun Wang, Johannes Buchen, Lijun Liu. Distinct slab interfaces imaged within the mantle transition zone. Nature Geoscience, 2020; DOI: 10.1038/s41561-020-00653-5

Note: The above post is reprinted from materials provided by Rice University.

East African Rift System is slowly breaking away, with Madagascar splitting into pieces

Final model for the East African Rift System. Hashed lines indicate newly discovered broad deforming zone. Arrows represent predicted tectonic plate motions. ABFZ—Andrew Bain Fracture Zone; IFZ—Indomed Fracture Zone; RSZ—Ranotsara shear zone. Figure created by D.S. Stamps.
Final model for the East African Rift System. Hashed lines indicate newly discovered broad deforming zone. Arrows represent predicted tectonic plate motions. ABFZ—Andrew Bain Fracture Zone; IFZ—Indomed Fracture Zone; RSZ—Ranotsara shear zone. Figure created by D.S. Stamps.

The African continent is slowly separating into several large and small tectonic blocks along the diverging East African Rift System, continuing to Madagascar — the long island just off the coast of Southeast Africa — that itself will also break apart into smaller islands.

These developments will redefine Africa and the Indian Ocean. The finding comes in a new study by D. Sarah Stamps of the Department of Geosciences for the journal Geology. The breakup is a continuation of the shattering of the supercontinent Pangea some 200 million years ago.

Rest assured, though, this isn’t happening anytime soon.

“The rate of present-day break-up is millimeters per year, so it will be millions of years before new oceans start to form,” said Stamps, an assistant professor in the Virginia Tech College of Science. “The rate of extension is fastest in the north, so we’ll see new oceans forming there first.”

“Most previous studies suggested that the extension is localized in narrow zones around microplates that move independent of surrounding larger tectonic plates,” Stamps said. The new GPS dataset of very precise surface motions in Eastern Africa, Madagascar, and several islands in the Indian Ocean reveal that the break-up process is more complex and more distributed than previously thought, according to the study, completed by Stamps with researchers from the University of Nevada-Reno, University of Beira Interior in Portugal, and the Institute and Observatory of Geophysics of Antananarivo at the University of Antananarivo in Madagascar itself.

In one region, the researchers found that extension is distributed across a wide area. The region of distributed extension is about 600 kilometers (372 miles) wide, spanning from Eastern Africa to whole parts of Madagascar. More precisely, Madagascar is actively breaking up with southern Madagascar moving with the Lwandle microplate — a small tectonic block — and a piece of central Madagascar is moving with the Somalian plate. The rest of the island is found to be deforming nonrigidly, Stamps added.

Also working on the paper was geosciences Ph.D. student Tahiry Rajaonarison, who previously was a master’s student at Madagascar’s University of Antananarivo. He assisted Stamps in 2012 in collecting GPS data that was used in this study. He joined Virginia Tech in 2015 and returned to Madagascar later to collect more data as the lead on a National Geographic Society grant. “Leading a team to collect GPS data in Madagascar in summer 2017 was an amazing field experience,” Rajaonarison said.

The team used new surface motion data and additional geologic data to test various configurations of tectonic blocks in the region using computer models. Through a comprehensive suite of statistical tests, the researchers defined new boundaries for the Lwandle microplate and Somalian plate. This approach allowed for testing if surface motion data are consistent with rigid plate motion.

Final model for the East African Rift System.

“Accurately defining plate boundaries and assessing if continents diverge along narrowly deforming zones or through wide zones of diffuse deformation is crucial to unraveling the nature of continental break-up,” Stamps said. “In this work, we have redefined how the world’s largest continental rift is extending using a new GPS velocity solution.”

The discovery of the broad deforming zone helps geoscientists understand recent and ongoing seismic and volcanic activity happening in the Comoros Islands, located in the Indian Ocean between East Africa and Madagascar. The study also provides a framework for future studies of global plate motions and investigations of the forces driving plate tectonics for Stamps and her team.

Reference:
D.S. Stamps, C. Kreemer, R. Fernandes, T.A. Rajaonarison, G. Rambolamanana. Redefining East African Rift System kinematics. Geology, 2020; DOI: 10.1130/G47985.1

Note: The above post is reprinted from materials provided by Virginia Tech.

Eomonachus belegaerensis : New fossil seal species rewrites history

An artist impression of the newly discovered extinct monk seal species Credit: Jaime Bran. Copyrigh: Museum of New Zealand Te Papa.
An artist impression of the newly discovered extinct monk seal species Credit: Jaime Bran. Copyrigh: Museum of New Zealand Te Papa.

The discovery, published today in the Proceedings of the Royal Society, radically changes scientists’ understanding of how seal species evolved around the world.

It came after researchers examined seven preserved fossil specimens, including a complete skull, found by local fossil hunters on south Taranaki beaches in New Zealand between 2009 and 2016.

The new species is named Eomonachus belegaerensis, (meaning ‘dawn monk seal from Belegaer’) after the sea of Belegaer, which lies west of Middle Earth in J.R.R. Tolkien’s Lord of the Rings.

Around 2.5 metres in length and weighing around 200 — 250kg, Eomonachus belegaerensis lived in the waters around New Zealand some 3 million years ago.

It was previously thought that all true seals originated in the North Atlantic, with some later crossing the equator to live as far south as Antarctica.

Eomonachus now shows that many ancient seals, including the ancestors of today’s monk, elephant and Antarctic seals, actually evolved in the Southern Hemisphere.

Monash palaeontologist James Rule, a PhD candidate at the Biomedicine Discovery Institute, led the research as part of a trans-Tasman collaboration involving Monash University and Museums Victoria in Australia, and Te Papa and Canterbury Museum in New Zealand. The study was supervised and co-authored by Dr Justin Adams (Monash Biomedicine Discovery Institute), Dr Erich Fitzgerald (Museums Victoria), and Associate Professor Alistair Evans (School of Biological Sciences).

“This new species of extinct monk seal is the first of its kind from the Southern Hemisphere. Its discovery really turns seal evolution on its head,” Mr Rule said.

“Until now, we thought that all true seals originated in the Northern Hemisphere, and then crossed the equator just once or twice during their entire evolutionary history. Instead, many of them appear to have evolved in the southern Pacific, and then criss-crossed the equator up to eight times.”

Te Papa Museum of New Zealand curator of marine mammals and study collaborator Dr Felix Marx said the discovery was a triumph for citizen science.

“This new species has been discovered thanks to numerous, exceptionally well-preserved fossils — all of which were found by members of the public.”

Dr Marx is hopeful about future discoveries of new species in New Zealand’s ancient past.

“New Zealand is incredibly rich in fossils, and so far we have barely scratched the surface. Who knows what else is out there?” Dr Marx said.

About monk seals. Unlike their cold-loving relatives in the Arctic and Antarctic, Monk seals prefer the warmer waters of the Mediterranean, Hawai’i and — until their extinction there in the 1950s — the Caribbean. Monk seals are the most endangered groups of marine mammals, with fewer than 2000 individuals thought to be left in the wild. Hunting has driven populations down.

Reference:
James P. Rule, Justin W. Adams, Felix G. Marx, Alistair R. Evans, Alan J. D. Tennyson, R. Paul Scofield, Erich M. G. Fitzgerald. First monk seal from the Southern Hemisphere rewrites the evolutionary history of true seals. Proceedings of the Royal Society B: Biological Sciences, 2020; 287 (1938): 20202318 DOI: 10.1098/rspb.2020.2318

Note: The above post is reprinted from materials provided by Monash University.

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