98-Million-Year-Old Pollen-Feeding Beetle Found Preserved in Amber

Apr 14, 2021 by News Staff / Source 

Paleontologists have found an exceptionally preserved short-winged flower beetle and associated pollen aggregations and coprolites in a piece of mid-Cretaceous amber originating from northern Myanmar. The discovery provides the direct evidence of pollen-feeding in a Cretaceous beetle and confirms that diverse beetle lineages visited early angiosperms (flowering plants) in the Cretaceous period.

Ecological reconstruction of Pelretes vivificus in the Burmese amber forest; the flowers in the reconstruction are based on Lijinganthus revoluta. Image credit: J. Sun.

Beetles are often cited as likely candidates for the earliest pollinators of angiosperms due to their long evolutionary history.

Ii has been suggested that early associations between beetles and angiosperms in the Cretaceous played a key role in the diversification of both groups.

Until now, pollination in beetles has been determined only on the basis of amber inclusions being preserved alongside pollen grains, possessing morphological features interpreted as possibly facilitating pollination, and having living relatives that are known to feed on pollen.

The newly-identified pollen-feeding beetle, named Pelretes vivificus, lived 98.2 million year ago in what is now Myanmar.

Its closest relatives are short-winged flower beetles (family Kateretidae) that today occur in Australia, visiting a diverse range of flowers and feeding on their pollen.

“Pelretes vivificus is associated with clusters of pollen grains, suggesting that short-winged flower beetles visited angiosperms in the Cretaceous,” said Professor Chenyang Cai, a paleontologist at the Nanjing Institute of Geology and Palaeontology.

“Some aspects of the beetle’s anatomy, such as its hairy abdomen, are also adaptations associated with pollination.”

The piece of amber examined by the team came from a mine in the Hukawng Valley, Kachin State, northern Myanmar.

“Besides the unparalleled abundance of fossil insects, the amber dates back to the mid-Cretaceous, right when angiosperms were taking off,” said Dr. Erik Tihelka, an entomologist and paleontologist at the University of Bristol.

Photomicrographs of Pelretes vivificus from mid-Cretaceous Burmese amber: (a) habitus, dorsal view, with inset highlighting a Tricolpopollenites pollen grain; (b) head of Pelretes vivificus, dorsal view; (c) habitus, ventral view; (d) head of Pelretes vivificus, ventral view (area indicated in c); (e) protarsus of Pelretes vivificus; (f) metatarsus of Pelretes vivificus; (g) abdominal apex of Pelretes vivificus, dorsal view (area indicated in a), with arrowheads highlighting pollen grains. Abbreviations: a1–11 – antennomeres 1–11; abd – abdomen; el – elytra; ey – eye; he – head; ma – mandibles; mp4 – maxillary palpomere 4; mtt1–5 – metatarsomeres 1–5; pg – pollen grain; mtv – metaventrite; pr – pronotum; ps – prosternum; pt2, 4 and 5 – protarsomeres 2, 4 and 5; se – sensory cell. The images in a, b, e and f were obtained under normal reflected light; the others were obtained under confocal laser scanning microscopy. Scale bars – 200 μm in a and c; 100 μm in b, d and g; 50 μm in e and f. Image credit: Tihelka et al.,

 doi: 10.1038/s41477-021-00893-2.

While Pelretes vivificus is not the first pollinating beetle to be described from Cretaceous amber, this unique specimen preserves a bizarre clue about its diet.

The fossil is associated with beetle coprolites that provide a very unusual but important insight into the diet of short-winged flower beetles in the Cretaceous.

The coprolites are completely composed of pollen, the same type that is found in clusters surrounding the beetle and attached to its body, which suggest that Pelretes vivificus visited angiosperms to feed on their pollen.

This finding provides a direct link between early flowering plants in the Cretaceous and their insect visitors.

It shows that these insect fossils were not just incidentally co-preserved with pollen, but that there was a genuine biological association between the two.

“The pollen associated with the beetle can be assigned to the fossil genus Tricolpopollenites,” said Dr. Liqin Li, a fossil pollen specialist at the Nanjing Institute of Geology and Palaeontology.

“This group is attributed to the eudicots, a living group of derived angiosperms, that includes the orders Malpighiales and Ericales.”

“This shows that pollinators took advantage of early angiosperms soon after their initial diversification and visited a diverse range of groups by the mid-Cretaceous,” Professor Cai added.

The team’s paper was published in the journal Nature Plants.

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E. Tihelka et al. Angiosperm pollinivory in a Cretaceous beetle. Nat. Plants, published online April 12, 2021; doi: 10.1038/s41477-021-00893-2

 

China’s Bitcoin Miners Will Consume as Much Energy as Mid-Sized Country within Three Years

Apr 14, 2021 by Enrico de Lazaro

Given the current trends in Bitcoin mining, Chinese researchers estimate that the energy consumption from this process in their country alone will peak in 2024 at 296.59 Twh (terawatt-hours) and generate 130.5 million metric tons of carbon emission.

The annual energy consumption of the Bitcoin blockchain in China is expected to peak in 2024 at 296.59 Twh and generate 130.50 million metric tons of carbon emission. Image credit: Aaron Olson.

As Bitcoin attracted considerable amount of attention in recent years, its underlying core mechanism, namely blockchain technology, has also quickly gained popularity.

Due to its key characteristics such as decentralization, auditability, and anonymity, blockchain is widely regarded as one of the most promising and attractive technologies for a variety of industries, such as supply chain finance, production operations management, logistics management, and the Internet of Things.

Despite its promises and attractiveness, mining Bitcoin requires constantly expending and/or expanding computer processing power, which is associated with increasing energy consumption.

In new research, Dr. Shouyang Wang from the University of Chinese Academy of Sciences and colleagues investigated carbon emission flows of Bitcoin blockchain operation in China using a simulation-based Bitcoin blockchain carbon emission model.

They found that without any policy interventions, the annual energy consumption of the Bitcoin blockchain in China will peak in 2024 at 296.59 Twh and generate 130.50 million metric tons of carbon emission.

These amounts exceed the entire annual greenhouse gas emissions outputs of entire mid-sized countries such as the Czech Republic and Qatar.

“Policy interventions are critical to reduce these impacts,” the researchers said.

“Feeding different scenarios into the model, however, we found that current policies like carbon taxation are not effective at curbing emissions from the Bitcoin industry.”

“Instead, we found that individual site regulation policies for Bitcoin miners represent the best way to alter the current energy consumption structure and reduce future emissions from the blockchain operation.”

A paper on the findings was published in the journal Nature Communications.

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S. Jiang et al. 2021. Policy assessments for the carbon emission flows and sustainability of Bitcoin blockchain operation in China. Nat Commun 12, 1938; doi: 10.1038/s41467-021-22256-3

 

Aboriginal Australians Used Boomerangs as Retouchers

Apr 14, 2021 by News Staff / Source

New research by Griffith University and University of Cape Town scientists provides the first traceological evidence of multipurpose nature of Australian hardwood boomerangs.

Australian Luritja man demonstrating method of attack with boomerang under cover of shield, c. 1920. Image credit: National Museum of Australia.

“Australian lithic assemblages contain a great number of retouched tools,” said lead author Eva Martellott from the Australian Research Centre for Human Evolution at Griffith University and her colleagues.

“Despite this fact, however, material evidence for, and studies, on the retouching tools utilised to create these technologies are limited, especially regarding their use in percussion retouch.”

“Indirect evidence found in ethnographic literature suggests that wooden items — specifically boomerangs — were frequently utilised as retouchers.”

In the study, the researchers analyzed microscopic traces on the surfaces of 100 ancient boomerangs from across each Australian state and territory.

By using a traceological method, they were able to more clearly see what tasks the boomerangs were used for by Aboriginal Australians in the past.

Retouch-induced marks were identified on 26% of the boomerangs examined by Martellotta et al. and were comparable to those traces observed on the surfaces of ancient European bone retouchers. Image credit: Martellotta et al., doi: 10.1016/j.jasrep.2021.102967.

“Not all boomerangs come back. Most are used for hunting and fighting purposes, whereas the returning ones are often children’s toys or used for games and learning purposes,” Martellotta said.

“We found specific marks related to the shaping of stone tools.”

“These marks are not new in archaeology — they are also identified on bone fragments in archaeological sites in Europe.”

“Here, the Neanderthals used them to modify the shape of stone tools, starting 500,000 years ago.”

“Our findings constitute the first traceological identification of hardwood boomerangs being used for shaping stone tools in various Aboriginal Australian contexts and emphasises the multipurpose nature of daily tools like boomerangs in Aboriginal culture.”

The findings were published in the Journal of Archaeological Science: Reports.

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Eva Francesca Martellotta et al. 2021. New data from old collections: Retouch-induced marks on Australian hardwood boomerangs. Journal of Archaeological Science: Reports 37: 102967; doi: 10.1016/j.jasrep.2021.102967

 

Neanderthal Nuclear DNA Found in Paleolithic Cave Sediments

Apr 16, 2021 by News Staff / Source

An international team of scientists has developed new methods for the enrichment and analysis of nuclear DNA from sediments, and applied them to cave deposits in Europe and Siberia dated to between approximately 200,000 and 50,000 years ago.

Vernot et al. extracted Neanderthal nuclear DNA from cave sediments. Image credit: Tyler B. Tretsven.

Skeletal remains are important sources of Pleistocene hominin DNA, but are rarely recovered at archaeological sites.

Mitochondrial DNA (mtDNA) has been retrieved from cave sediments, but provides limited value for studying population relationships.

Although nuclear DNA contains far more information, its retrieval from sediments presents substantial challenges. It’s far less abundant than mtDNA and difficult to distinguish from other non-hominin mammalian and microbial DNA, which dominates the genetic material often present in ancient sediments.

To address these challenges, Dr. Benjamin Vernot from the Department of Evolutionary Genetics at the Max-Planck-Institute for Evolutionary Anthropology and his colleagues developed methods to recover, enrich and analyze nuclear DNA from cave sediments.

“There are lots of places in the human genome that are very similar to a bear’s DNA, for example,” Dr. Vernot said.

“We specifically targeted regions in the genome where we could be confident of isolating only human DNA, and we also designed methods to measure our success in removing non-human DNA.”

“We wanted to be confident that we weren’t accidentally looking at some unknown species of hyena.”

Specifically, the researchers applied their approach to extract nuclear DNA from more than 150 sediment samples from three caves: Galería de las Estatuas in northern Spain and Chagyrskaya and Denisova caves in the Altai Mountains of southern Siberia.

They detected a population replacement in Spain approximately 100,000 years ago, accompanied by a turnover of mtDNA.

They also identified two radiation events in Neanderthal history during the early part of the Late Pleistocene.

“The dawn of nuclear DNA analysis of sediments massively extends the range of options to tease out the evolutionary history of ancient humans,” Dr. Vernot said.

“By freeing the field of ancient DNA from the constraints of finding human remains and expanding the number of sites potentially suitable for investigation, we can now study the DNA from many more human populations, and from many more places, than has previously been thought possible,” added Dr. Matthias Meyer, also from the Department of Evolutionary Genetics at the Max-Planck-Institute for Evolutionary Anthropology.

The findings were published in the journal Science.

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Benjamin Vernot et al. Unearthing Neanderthal population history using nuclear and mitochondrial DNA from cave sediments. Science, published online April 15, 2021; doi; 10.1126/science.abf1667

 

New Fossils of Homo erectus Found in Kenya

Apr 13, 2021 by News Staff / Source

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Paleoanthropologists have uncovered two new specimens of Homo erectus at the East Turkana site in Kenya. They’ve also verified the age of a skull fragment of Homo erectus — one of the oldest specimens attributable to this species — found earlier at the same site.

This is an artist’s reconstruction of Homo erectus. Image credit: Yale University.

“Homo erectus is the first hominin that we know about that has a body plan more like our own and seemed to be on its way to being more human-like,” said Dr. Ashley Hammond, a researcher at the American Museum of Natural History.

“It had longer lower limbs than upper limbs, a torso shaped more like ours, a larger cranial capacity than earlier hominins, and is associated with a tool industry — it’s a faster, smarter hominin than Australopithecus and earliest Homo.”

In 1974, scientists at the East Turkana site in Kenya found one of the oldest specimens of Homo erectus: a 1.9-million-year-old skull fragment. The specimen is only surpassed in age by a 2-million-year-old skull specimen in South Africa.

But there was pushback within the field, with some paleoanthropologists arguing that the East Turkana specimen could have come from a younger fossil deposit and was possibly moved by water or wind to the spot where it was found.

To pinpoint the locality, Dr. Hammond and colleagues relied on archival materials and geological surveys.

‘We had to go through hundreds of pages from old reports and published research, reassessing the initial evidence and searching for new clues,” said Dr. Dan Palcu, a geoscientist at the University of São Paulo and Utrecht University.

“We also had to use satellite data and aerial imagery to find out where the fossils were discovered, recreate the scene, and place it in a larger context to find the right clues for determining the age of the fossils.”

Although located in a different East Turkana collection area than initially reported, the skull specimen was found in a location that had no evidence of a younger fossil outcrop that may have washed there. This supports the original age given to the fossil.

A partial pelvis of Homo erectus found at the East Turkana site in Kenya. Image credit: A. Hammond / American Museum of Natural History.

Within 50 m of the reconstructed location, the researchers found two new specimens: a partial pelvis and a foot bone.

“Although they could be from the same individual, there’s no way to prove that after the fossils have been separated for so long,” they said.

“But they might be the earliest postcrania specimens yet discovered for Homo erectus.”

“Our work also suggests that this early Homo erectus was found in a paleoenvironment that included primarily grazers that prefer open environments to forest areas and was near a stable body of water, as documented by freshwater sponges preserved in the rocks.”

The findings were published in the journal Nature Communications.

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A.S. Hammond et al. 2021. New hominin remains and revised context from the earliest Homo erectus locality in East Turkana, Kenya. Nat Commun 12, 1939; doi: 10.1038/s41467-021-22208-x

 

Black Phosphorus-Based Coating Has Antimicrobial Activity

Apr 13, 2021 by News Staff / Source

Few-layered black phosphorus is highly antimicrobial toward resistant bacteria and fungal species; it is one of the thinnest antimicrobial coatings developed to date and could be used on wound dressings and implants, according to a paper published in the journal ACS Applied Materials & Interfaces.

Black phosphorus is effective at killing microbes when spread in nanothin layers on surfaces like titanium and cotton. Image credit: RMIT University.

Antimicrobial resistance has rendered many conventional therapeutic measures, such as antibiotics, ineffective.

This makes the treatment of infections from pathogenic microorganisms a major growing health, social, and economic challenge.

“Finding one material that could prevent both bacterial and fungal infections is a significant advance,” said Dr. Aaron Elbourne, a researcher in the School of Science at RMIT University.

“These pathogens are responsible for massive health burdens and as drug-resistance continues to grow, our ability to treat these infections becomes increasingly difficult.”

As black phosphorus breaks down, it oxidizes the surface of bacteria and fungal cells. This process, known as cellular oxidisation, ultimately works to rip them apart.

Dr. Elbourne and colleagues tested the effectiveness of nanothin layers of black phosphorus against five common bacteria strains, including Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA), as well as five types of fungus, including Candida auris.

In just two hours, up to 99% of bacterial and fungal cells were destroyed.

Importantly, black phosphorus also began to self-degrade in that time and was entirely disintegrated within 24 hours — an important feature that shows the material would not accumulate in the body.

The authors also identified the optimum levels of black phosphorus that have a deadly antimicrobial effect while leaving human cells healthy and whole.

“Black phosphorus breaks down in the presence of oxygen, which is normally a huge problem for electronics and something we had to overcome with painstaking precision engineering to develop our technologies,” said Dr. Sumeet Walia, a researcher in the School of Engineering at RMIT University.

“But it turns out materials that degrade easily with oxygen can be ideal for killing microbes — it’s exactly what the scientists working on antimicrobial technologies were looking for. So our problem was their solution.”

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Z.L. Shaw et al. Broad-Spectrum Solvent-free Layered Black Phosphorus as a Rapid Action Antimicrobial. ACS Appl. Mater. Interfaces, published online April 12, 2021; doi: 10.1021/acsami.1c01739

 

Study: 5,200 Tons of Extraterrestrial Dust Reach Earth’s Surface Each Year

Apr 13, 2021 by Enrico de Lazaro

In a new paper published in the journal Earth and Planetary Science Letters, an international team of researchers presents the results from a long-term collection of extraterrestrial particles performed during the last two decades near the French-Italian CONCORDIA station in Antarctica.

These SEM images show cosmic spherules and unmelted micrometeorites from the CONCORDIA collection, from left to right, top to bottom: glassy cosmic spherule, stony cosmic spherule, partially melted micrometeorite, unmelted fine-grained micrometeorite. Image credit: Rojas et al., 

doi: 10.1016/j.epsl.2021.116794.

“More than a century after the discovery of cosmic spherules in deep-sea sediments, the origin, composition and magnitude of the cosmic dust accretion on Earth is still a matter of debate,” said lead author Julien Rojas from the Université Paris-Saclay and colleagues.

“Extraterrestrial dust flux studies have been performed before atmospheric entry, while collections at the Earth’s surface of both melted and unmelted micrometeorites were achieved in numerous locations such as the deep sea, deserts, sedimentary rocks and the polar ice caps.”

“Although all these studies demonstrated that the annual extraterrestrial mass input on Earth is essentially carried by sub-millimeter particles, the precise mass distribution of particles down to a few tens of μm and its integrated value at the Earth surface remain uncertain.”

The researchers performed several independent collections of micrometeorites from ultra-clean snow samples in the CONCORDIA station located at Dome C, in the central regions of Antarctica.

“Dome C is an ideal collection spot due to the low accumulation rate of snow and the near absence of terrestrial dust,” they said.

They identified a total of 1,280 unmelted micrometeorites and 808 cosmic spherules with diameters between 30 and 350 μm and analyzed them using conventional scanning electron microscopy techniques.

Within that size range, we measured mass fluxes of 3.0 μg/m2*yr for micrometeorites and 5.6 μg/m2*yr for cosmic spherules.

Extrapolated to the global flux of particles in the 12-700 μm diameter range, the mass flux of dust at Earth’s surface is 5,200 tons/yr (1,600 and 3,600 tons/yr of micrometeorites and cosmic spherules, respectively).

“This total mass flux of extraterrestrial particles at the Earth’s surface is important for many astrophysical and geophysical issues,” the authors said.

“Our numerical simulations suggest that most of micrometeorites and cosmic spherules originate from Jupiter family comets and a minor part from the main asteroid belt.”

“The total dust mass input before atmospheric entry is estimated at 15,000 tons/yr.”

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J. Rojas et al. 2021. The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial dust on Earth. Earth and Planetary Science Letters 560: 116794; doi: 10.1016/j.epsl.2021.116794

Yukon Wolves Survived Ice-Age Extinction Thanks to Changes in Their Diet

Apr 12, 2021 by News Staff / Source

Gray wolves (Canis lupus) from the Yukon Territory, Canada, survived the extinction at the end of the last Ice Age by adapting their diet over thousands of years — from a primary reliance on horses (Equus sp.) during the Pleistocene, to moose (Alces alces) and caribou (Rangifer tarandus) today.

Gray wolves take down a horse on the mammoth-steppe habitat of Beringia during the Late Pleistocene, around 25,000 years ago. Image credit: Julius Csotonyi.

A research team led by Dr. Danielle Fraser from the Canadian Museum of Nature, Carleton University, and Smithsonian National Museum of Natural History, investigated if and how diets of Yukon gray wolves changed from the Pleistocene (50,000 to 26,000 years ago) to the recent times.

“We can study the change in diet by examining wear patterns on the teeth and chemical traces in the wolf bones,” said Zoe Landry, a student at Carleton University.

“These can tell us a lot about how the animal ate, and what the animal was eating throughout its life, up until about a few weeks before it died.”

Dr. Fraser, Landry and their colleagues relied on established models that can determine an animal’s eating behavior by examining microscopic wear patterns on its teeth.

Scratch marks indicate the wolf would have been consuming flesh, while the presence of pits would suggest chewing and gnawing on bones, likely as a scavenger.

The analysis showed that scratch marks prevailed in both the ancient and modern wolf teeth, meaning that the wolves continued to survive as primary predators, hunting their prey.

Their modern diet is well established; the diet of the ancient wolves was assessed by looking at the ratios of carbon and nitrogen isotopes extracted from collagen in the bones. Relative levels of the isotopes can be compared with established indicators for specific species.

The results showed that horses, which went extinct during the Pleistocene, accounted for about half of the gray wolf diet. About 15% came from caribou and Dall’s sheep, with some mammoth mixed in.

At this time, the ancient wolves would have co-existed with other large predators such as scimitar cats and short-faced bears.

The eventual extinction of these predators could have created more opportunity for the wolves to transition to new prey species.

“This is really a story of Ice Age survival and adaptation, and the building up of a species towards the modern form in terms of ecological adaptation,” said Dr. Grant Zazula, a paleontologist with the Palaeontology Program of Government of Yukon.

The team’s paper was published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

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Zoe Landry et al. 2021. Dietary reconstruction and evidence of prey shifting in Pleistocene and recent gray wolves (Canis lupus) from Yukon Territory. Palaeogeography, Palaeoclimatology, Palaeoecology 571: 110368; doi: 10.1016/j.palaeo.2021.110368