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Shocking 439-Million-Year-Old “Shark” Forces Scientists To Rethink the Timeline of Evolution
These discoveries provide tangible evidence of massive vertebrate group diversification tens of millions of years before the start of the so-called “Age of Fishes” about 420 million years ago.
The ancient shark was found in China and is humans’ oldest jawed ancestor.
The apex predators of the ocean are often shown as living sharks. Paleontologists have been able to locate remains of ancient ancestors that originate from the Palaeozoic era, which dates back hundreds of millions of years ago. These ancient “sharks,” often referred to as acanthodians, were covered with spines. Unlike modern sharks, they evolved bony “armor” around their paired fins.
Scientists were shocked by the age of a newly discovered acanthodian species from China. The discovery is the oldest undisputed jawed fish and precedes the first acanthodian body fossils by around 15 million years.
The researchers’ findings were recently published in the journal Nature.
Life reconstruction of Fanjingshania renovata. Credit: Zhang Heming
Reconstructed from thousands of tiny skeletal fragments, Fanjingshania, named after the famous UNESCO World Heritage Site Fanjingshan, is a bizarre fish with an external bony “armor” and multiple pairs of fin spines that set it apart from living jawed fish, cartilaginous sharks, and rays, and bony ray- and lobe-finned fish.
Examination of Fanjingshania by a team of researchers from the Chinese Academy of Sciences, Qujing Normal University, and the University of Birmingham revealed that the species is anatomically close to groups of extinct spiny “sharks” collectively known as acanthodians. Unlike modern sharks, acanthodians have skin ossifications of the shoulder region that occur primitively in jawed fish.
A reconstruction of Fanjingshania renovata in the ocean. Credit: Fu Boyuan and Fu Baozhong
The fossil remains of Fanjingshania were discovered in bone bed samples of the Rongxi Formation in Shiqian County, Guizhou Province, China.
These discoveries provide verifiable proof that major vertebrate groupings began to diversify tens of millions of years before the 420 million-year-old start of the so-called “Age of Fishes”
The scientists discovered characteristics that distinguish Fanjingshania from every other known vertebrate. It has pectoral, pre-pectoral, and pre-pelvic spines that fuse together as a single unit with dermal shoulder girdle plates. Furthermore, it was found that the shoulder plates’ ventral and lateral portions extend to the pectoral fin spines’ posterior edge. The species possesses distinctive trunk scales, and the crowns of these scales are made up of a row of tooth-like elements (odontodes) that are adorned with irregular nodose ridges. Strangely, the growth of dentine is recorded in the scales but not in other parts of the dermal skeleton, such as the fin spines.
An alternative view of Fanjingshania renovata. Credit: Zhang Heming
“This is the oldest jawed fish with known anatomy,” said Prof. Zhu Min from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences. “The new data allowed us to place Fanjingshania in the phylogenetic tree of early vertebrates and gain much-needed information about the evolutionary steps leading to the origin of important vertebrate adaptations such as jaws, sensory systems, and paired appendages.”
From the outset, it was clear to the scientists that Fanjingshania’s shoulder girdle, with its array of fin spines, is key to pinpointing the new species’ position in the evolutionary tree of early vertebrates. They found that a group of acanthodians, known as climatiids, possess the full complement of shoulder spines recognized in Fanjingshania. What is more, in contrast to normal dermal plate development, the pectoral ossifications of Fanjingshania and the climatiids are fused to modified trunk scales. This is seen as a specialization from the primitive condition of jawed vertebrates where the bony plates grow from a single ossification center.
Fragment of the pectoral dermal skeleton (part of a pectoral spine fused to shoulder girdle plate) of Fanjingshania renovata shown in ventral view. Credit: Andreev, et al
Unexpectedly, the fossil bones of Fanjingshania show evidence of extensive resorption and remodeling that are typically associated with skeletal development in bony fish, including humans.
“This level of hard tissue modification is unprecedented in chondrichthyans, a group that includes modern cartilaginous fish and their extinct ancestors,” said lead author Dr. Plamen Andreev, a researcher at Qujing Normal University. “It speaks about greater than currently understood developmental plasticity of the mineralized skeleton at the onset of jawed fish diversification.”
The resorption features of Fanjingshania are most apparent in isolated trunk scales that show evidence of tooth-like shedding of crown elements and removal of dermal bone from the scale base. Thin-sectioned specimens and tomography slices show that this resorptive stage was followed by the deposition of replacement crown elements. Surprisingly, the closest examples of this skeletal remodeling are found in the dentition and skin teeth (denticles) of extinct and living bony fish. In Fanjingshania, however, the resorption did not target individual teeth or denticles, as occurred in bony fish, but instead removed an area that included multiple scale denticles. This peculiar replacement mechanism more closely resembles skeletal repair than the typical tooth/denticle substitution of jawed vertebrates.
The Chongqing fish fossil depository is the world’s only early Silurian Lagerstätte which preserves complete, head-to-tail jawed fishes, providing a peerless chance to peek into the proliferating “dawn of fishes”. Credit: NICE Tech/ScienceApe
A phylogenetic hypothesis for Fanjingshania that uses a numeric matrix derived from observable characters confirmed the researchers’ initial hypothesis that the species represents an early evolutionary branch of primitive chondrichthyans. These results have profound implications for our understanding of when jawed fish originated since they align with morphological clock estimates for the age of the common ancestor of cartilaginous and bony fish, dating it to around 455 million years ago, during a period known as the Ordovician.
These results tell us that the absence of undisputed remains of jawed fish of Ordovician age might be explained by the under-sampling of sediment sequences of comparable antiquity. They also point towards a strong preservation bias against teeth, jaws, and articulated vertebrate fossils in strata coeval with Fanjingshania.
“The new discovery puts into question existing models of vertebrate evolution by significantly condensing the timeframe for the emergence of jawed fish from their closest jawless ancestors. This will have a profound impact on how we assess evolutionary rates in early vertebrates and the relationship between morphological and molecular change in these groups,” said Dr. Ivan J. Sansom from the
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Democrats withdraw letter urging Biden to rethink Ukraine war strategy
They also worried that the letter could create more pressure on Biden as he tries to sustain domestic support for the war effort, at a time when the region is heading into a potentially difficult winter and Republicans are threatening to cut aid to Ukraine if they retake Congress.
On Tuesday, Jayapal said the letter had been drafted several months ago and “released by staff without vetting.” She also sought to distance Democrats from recent comments by House Minority Leader Kevin McCarthy (R-Calif.), who suggested that a GOP-led House would not support additional aid to Ukraine.
“As Chair of the Caucus, I accept responsibility for this,” Jayapal said in a statement. “The proximity of these statements created the unfortunate appearance that Democrats, who have strongly and unanimously supported and voted for every package of military, strategic, and economic assistance to the Ukrainian people, are somehow aligned with Republicans who seek to pull the plug on American support for President Zelensky and the Ukrainian forces.”
Earlier, several of the letter’s signatories also walked back their support for the letter, saying it was written months ago. Late Monday, Rep. Mark Pocan (D-Wis.) seemed to commiserate with someone critical of the letter on Twitter.
“Hear you. First, this was written in July & I have no idea why it went out now. Bad timing,” Pocan tweeted.
“Timing in diplomacy is everything,” Rep. Sara Jacobs (D-Calif.), one of the letter’s other signatories, tweeted Tuesday morning. “I signed this letter on June 30, but a lot has changed since then. I wouldn’t sign it today. We have to continue supporting Ukraine economically and militarily to give them the leverage they need to end this war.”
Timing in diplomacy is everything.
I signed this letter on June 30, but a lot has changed since then. I wouldn’t sign it today.
We have to continue supporting Ukraine economically and militarily to give them the leverage they need to end this war. https://t.co/jEJlTK1hJI
— Congresswoman Sara Jacobs (@RepSaraJacobs) October 25, 2022
In the original letter to the White House, dated Oct. 24 and first reported by The Washington Post, the lawmakers called on Biden to pursue a “proactive diplomatic push, redoubling efforts to seek a realistic framework for a cease fire.”
The liberal Democrats noted that the war’s disastrous consequences are increasingly felt far beyond Ukraine, including elevated food and gas prices in the United States and spikes in the price of wheat, fertilizer and fuel that have created global food shortages, not to mention the danger of a nuclear attack by Moscow.
The letter was signed by some of the best-known and most outspoken liberal Democrats in Congress, including Reps. Jamie Raskin (Md.), Alexandria Ocasio-Cortez (N.Y.), Cori Bush (Mo.), Ro Khanna (Calif.) and Ilhan Omar (Minn.).
For now, their position remains a minority in the Democratic Party, which has overwhelmingly supported Biden’s denunciations of Russia and his spearheading of a global coalition to funnel massive support to Ukraine. Biden has framed the conflict as part of his broader view that the world is witnessing a historic confrontation between authoritarianism and democracy.
White House spokesman John Kirby said Monday that the administration appreciated the lawmakers’ “very thoughtful concerns” but signaled no shift in the administration strategy on Ukraine.
“We’re not going to have conversations with the Russian leadership without the Ukrainians being represented,” Kirby said during a briefing with reporters Monday. “Mr. Zelensky gets to determine — because it’s his country — what success looks like and when to negotiate.”
Privately, some administration officials questioned the timing of the letter, which came two weeks before midterm elections and one week after McCarthy said the GOP could oppose more aid to Ukraine.
Jayapal issued a statement Monday evening “clarifying” the position the progressives outlined in the letter, stressing that they still supported Ukraine and Biden’s commitment to ensure Ukraine is represented in any discussions about its future.
“Let me be clear: we are united as Democrats in our unequivocal commitment to supporting Ukraine in their fight for their democracy and freedom in the face of the illegal and outrageous Russian invasion,” Jayapal said. “Diplomacy is an important tool that can save lives — but it is just one tool.”
Democrats were not made aware that the letter would be issued Monday, including those who had signed the letter over the summer, according to three congressional aides who spoke on the condition of anonymity to discuss sensitive matters. One person close to the progressive caucus, who spoke on the condition of anonymity to discuss private conversations, said it was strange to publicly release a letter with only 30 signatures out of the 220 Democrats in the House.
Many blamed Jayapal for the misstep, with several aides saying they believed this could tarnish her chances of winning a spot in Democratic leadership. Jayapal has made preliminary calls to her colleagues to express interest in running for a leadership position, leaving the impression among some members that she would challenge Rep. Katherine M. Clark (D-Mass.), who is also a member of the progressive caucus, for a presumed No. 2 spot in the party.
Marianna Sotomayor contributed to this report.
Kelly Ripa would rethink doing ‘Live’ with Regis Philbin after drama
Kelly Ripa would rethink co-hosting “Live” with Regis Philbin if she knew about the ABC show’s behind-the-scenes drama.
“I wouldn’t have done it. No,” the “Live Wire” author said on Tuesday’s episode of the “Not Skinny But Not Fat” podcast when asked about working with Regis Philbin from 2001 to 2011.
“If I had known [about the show’s issues] going in, I wouldn’t have done it. And how sad for me,” she continued. “Luckily, ignorance is bliss.”
Ripa explained that she “didn’t know that there was so much fighting between” Philbin and the network when she started the job.
“I was hyper-sensitive to the feelings all around me that this was like new and unusual terrain I was wading into,” the “All My Children” alum explained.
The “Hope & Faith” alum, who “couldn’t put her finger” on the feelings at the time, added, “It was sort of explained to me [that there were] these two battling forces within the company that I didn’t even know existed.”
Ripa noted that Philbin, who died in July 2020 at age 88, didn’t “need” a co-host.
“I take his side,” she said. “He should not have had to have a host assigned to him. That’s not fair. He paid his dues and he established this show.
“I felt for him because he was so famous and was so well-established.”
The “Live With Kelly and Ryan” host “advocated for” Philbin in her memoir, which was released last month, but Ripa was still blasted by Kathie Lee Gifford for speaking about the late talk show host at all.
The “Today” show alum, who co-hosted “Live” with Philbin from 1985 to 2000, told Fox 5’s Rosanna Scotto earlier this month that she was “not gonna read” the book.
Gifford, 69, called Philbin a “friend” and the “best partner,” saying she was “very sorry to see” headlines about him following the release of Ripa’s book.
Ripa, however, thanked the “Today” show alum for her comments on Tuesday. She explained that the diss gave her memoir “attention.”
Astronomers forced to rethink early Webb telescope findings
Astronomers have been so keen to use the new James Webb Space Telescope that some have got a little ahead of themselves. Many started analysing Webb data right after the first batch was released, on 14 July, and quickly posted their results on preprint servers — but are now having to revise them. The telescope’s detectors had not been calibrated thoroughly when the first data were made available, and that fact slipped past some astronomers in their excitement.
The revisions don’t so far appear to substantially change many of the exciting early results, such as the discovery of a number of candidates for the most distant galaxy ever spotted. But the ongoing calibration process is forcing astronomers to reckon with the limitations of early data from Webb.
Four revelations from the Webb telescope about distant galaxies
Figuring out how to redo the work is “thorny and annoying”, says Marco Castellano, an astronomer at the Italian National Institute of Astrophysics in Rome. “There’s been a lot of frustration,” says Garth Illingworth, an astronomer at the University of California, Santa Cruz. “I don’t think anybody really expected this to be as big of an issue as it’s becoming,” adds Guido Roberts-Borsani, an astronomer at the University of California, Los Angeles.
Calibration is particularly challenging for projects that require precise measurements of the brightness of astronomical objects, such as faint, faraway galaxies. For several weeks, some astronomers have been cobbling together workarounds so that they can continue their analyses1. The next official round of updates to Webb’s calibrations are expected in the coming weeks from the Space Telescope Science Institute (STScI) in Baltimore, Maryland, which operates the telescope. Those updates should shrink the error bars on the telescope’s calibrations from the tens of percentage points that have been bedevilling astronomers in some areas, down to just a few percentage points. And data accuracy will continue to improve as calibration efforts proceed over the coming months.
The STScI made it clear that the initial calibrations to the telescope were rough, says Jane Rigby, operations project scientist for Webb at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Much of the issue stems from the fact that Webb, which launched in December 2021, is a new telescope whose details are still being worked out. “It’s been a long time since the community has had a brand-new telescope in space — a big one with these amazingly transformative powers,” Rigby says.
“We knew it wasn’t going to be perfect right out of the box,” says Martha Boyer, an astronomer at the STScI who is helping to lead the calibration efforts2.
Calibration controversy
All telescopes need to be calibrated. This is usually done by observing a well-understood star such as Vega, a prominent star in the night sky. Astronomers look at the data being collected by the telescope’s various instruments — such as the brightness of the star in different wavelengths of light — and compare them with measurements of the same star from other telescopes and of laboratory standards.
Webb telescope spots CO2 on exoplanet for first time: what it means for finding alien life
Working with Webb data involves several types of calibration, but the current controversy is around one of the telescope’s main instruments, its Near Infrared Camera (NIRCam). In the six months after Webb launched, STScI researchers worked to calibrate NIRCam. But given the demands on Webb, they had only enough time to point it at one or two calibration stars, and to take data using just one of NIRCam’s ten detectors. They then estimated the calibrations for the other nine detectors. “That’s where there was a problem,” Boyer says. “Each detector will be a little bit different.”
Within days of the first Webb data release, non-peer-reviewed papers began appearing on the arXiv preprint server, reporting multiple candidates for the most distant galaxy ever recorded. These studies relied on the brightness of distant objects, measured with Webb at various wavelengths. Then, on 29 July, the STScI released an updated set of calibrations that were substantially different from what astronomers had been working with.
“This caused a little bit of panic,” says Nathan Adams, an astronomer at the University of Manchester, UK, who, along with his colleagues, pointed out the problem in a 9 August update to a preprint they had posted in late July3. “For those including myself who had written a paper within the first two weeks, it was a bit of — ‘Oh no, is everything that we’ve done wrong, does it all need to go in the bin?’”
A young observatory
To try to standardize all the measurements, the STScI is working through a detailed plan to point Webb at several types of well-understood star, and observe them with every detector in every mode for every instrument on the telescope4. “It just takes a while,” says Karl Gordon, an astronomer at the STScI who helps lead the effort.
Link: Webb telescope wows with first image of an exoplanet
In the meantime, astronomers have been reworking manuscripts that describe distant galaxies on the basis of Webb data. “Everyone’s gone back over and had a second look, and it’s not as bad as we thought,” Adams says. Many of the most exciting distant-galaxy candidates still seem to be at or near the distance originally estimated. But other preliminary studies, such as those that draw conclusions about the early Universe by comparing large numbers of faint galaxies, might not stand the test of time. Other fields of research, such as planetary studies, are not affected as much because they depend less on these preliminary brightness measurements.
“We’ve come to realize how much this data processing is an ongoing and developing situation, just because the observatory is so new and so young,” says Gabriel Brammer, an astronomer at the University of Copenhagen who has been developing Webb calibrations independent of the STScI.
In the long run, astronomers are sure to sort out the calibration and become more confident in their conclusions. But for now, Boyer says, “I would tell people to proceed with caution — whatever results they might be getting today might not be quite right in six months, when we have more information. It’s just sort of, ‘Proceed at your own risk.’”
“Astonishing” 500-Million-Year-Old Fossilized Brains Prompt a Rethink of the Evolution of Insects and Spiders
Stanleycaris hirpex. Credit: Sabrina Cappelli © Royal Ontario Museum
An ancient radiodont predator with three eyes reveals key information about the evolution of the arthropod body plan.
New research based on a cache of fossils that contains the brain and nervous system of a half-billion-year-old marine predator from the Burgess Shale called Stanleycaris has been revealed by the Royal Ontario Museum (ROM). Belonging to an ancient, extinct offshoot of the arthropod evolutionary tree called Radiodonta, Stanleycaris is distantly related to modern insects and spiders. These results shed light on the evolution of the arthropod brain, vision, and head structure.
“The details are so clear it’s as if we were looking at an animal that died yesterday.”
— Joseph Moysiuk
The findings were announced in the research paper, “A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation,” published on July 5, 2022, in the journal Current Biology.
Pair of fossil specimens of Stanleycaris hirpex, specimen ROMIP 65674.1-2. Credit: Photo by Jean-Bernard Caron, © Royal Ontario Museum
What has scientists most excited is what’s inside Stanleycaris’ head. The remains of the brain and nerves are still preserved after 506 million years in 84 of the fossils.
“While fossilized brains from the Cambrian Period aren’t new, this discovery stands out for the astonishing quality of preservation and the large number of specimens,” said Joseph Moysiuk, lead author of the research and a University of Toronto (U of T) PhD Candidate in Ecology and Evolutionary Biology, based at the Royal Ontario Museum. “We can even make out fine details such as visual processing centers serving the large eyes and traces of nerves entering the appendages. The details are so clear it’s as if we were looking at an animal that died yesterday.”
Turntable animation of Stanleycaris hirpex, including transparency to show internal organs. Credit: Animation by Sabrina Cappelli © Royal Ontario Museum
The new fossils reveal that the brain of Stanleycaris was composed of two segments, the protocerebrum, connected with the eyes, and the deutocerebrum, connected with the frontal claws.
“We conclude that a two-segmented head and brain has deep roots in the arthropod lineage and that its evolution likely preceded the three-segmented brain that characterizes all living members of this diverse animal phylum,” added Moysiuk.
In present-day arthropods like insects, the brain consists of protocerebrum, deutocerebrum, and tritocerebrum. While the difference in a segment may not sound game-changing, it in fact has radical scientific implications. Since repeated copies of many arthropod organs can be found in their segmented bodies, figuring out how segments line up between different species is key to understanding how these structures diversified across the group.
“These fossils are like a Rosetta Stone, helping to link traits in radiodonts and other early fossil arthropods with their counterparts in surviving groups.”
Reconstruction of a pair of Stanleycaris hirpex; upper individual has transparency of the exterior increased to show internal organs. Nervous system is shown in light beige, digestive system in dark red. Credit: Illustration by Sabrina Cappelli © Royal Ontario Museum
In addition to its pair of stalked eyes, Stanleycaris possessed a large central eye at the front of its head, a feature never before noticed in a radiodont. “The presence of a huge third eye in Stanleycaris was unexpected. It emphasizes that these animals were even more bizarre-looking than we thought, but also shows us that the earliest arthropods had already evolved a variety of complex visual systems like many of their modern kin” said Dr. Jean-Bernard Caron, ROM’s Richard Ivey Curator of Invertebrate Palaeontology, and Moysiuk’s PhD supervisor. “Since most radiodonts are only known from scattered bits and pieces, this discovery is a crucial jump forward in understanding what they looked like and how they lived,” added Caron, who is also an Associate Professor at the U of T, in Ecology & Evolution and Earth Sciences.
Paper summary, showing the interpretation of the nervous system from fossils of Stanleycaris and implications for understanding the evolution of the arthropod brain. The brain is represented in red and the nerve cords in purple. Credit: Photo by Jean-Bernard Caron © Royal Ontario Museum
In the Cambrian Period, radiodonts included some of the biggest animals around, with the famous “weird wonder” Anomalocaris reaching up to at least 1 meter in length. At no more than 20 cm long, Stanleycaris was small for its group, but at a time when most animals grew no bigger than a human finger, it would have been an impressive predator. Stanleycaris’ sophisticated sensory and nervous systems would have enabled it to efficiently pick out small prey in the gloom.
Reconstruction of Stanleycaris hirpex. Credit: Art by Sabrina Cappelli © Royal Ontario Museum
With large compound eyes, a formidable-looking circular mouth lined with teeth, frontal claws with an impressive array of spines, and a flexible, segmented body with a series of swimming flaps along its sides, Stanleycaris would have been the stuff of nightmares for any small bottom dweller unfortunate enough to cross its path.
- Fossil specimen of Stanleycaris hirpex. Dark material inside the head is the remains of nervous tissue, specimen ROMIP 65674.2. Credit: Photo by Jean-Bernard Caron © Royal Ontario Museum
- Fossil specimen of Stanleycaris hirpex. Dark material inside the head is the remains of nervous tissue, specimen ROMIP 65674.1. Credit: Photo by Jean-Bernard Caron © Royal Ontario Museum
About the Burgess Shale
For this research, Moysiuk and Caron studied a previously unpublished collection of 268 specimens of Stanleycaris. The fossils were primarily collected in the 1980s and 90s from rock layers above the famous Walcott Quarry site of the Burgess Shale in Yoho National Park, B.C., Canada, and are part of the extensive collection of Burgess Shale fossils housed at ROM.
The Burgess Shale fossil sites are located within Yoho and Kootenay National Parks and are managed by Parks Canada. Parks Canada is proud to work with leading scientific researchers to expand knowledge and understanding of this key period of earth history and to share these sites with the world through award-winning guided hikes. The Burgess Shale was designated a UNESCO World Heritage Site in 1980 due to its outstanding universal value and is now part of the larger Canadian Rocky Mountain Parks World Heritage Site.
Fossils of Stanleycaris can be seen by the public in the new Burgess Shale fossil display in the Willner Madge Gallery, Dawn of Life at ROM.
Reference: “A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation” by Joseph Moysiuk and Jean-Bernard Caron, 8 July 2022, Current Biology.
DOI: 10.1016/j.cub.2022.06.027
Major research funding support came from the National Sciences and Engineering Research Council of Canada, via a Vanier Canada Graduate Scholarship to Moysiuk and a Discovery Grant (no. 341944) to Caron.
500-million-year-old fossilized brains of Stanleycaris prompt a rethink of the evolution of insects and spiders
Royal Ontario Museum revealed new research based on a cache of fossils that contains the brain and nervous system of a half-billion-year-old marine predator from the Burgess Shale called Stanleycaris. Stanleycaris belonged to an ancient, extinct offshoot of the arthropod evolutionary tree called Radiodonta, distantly related to modern insects and spiders. These findings shed light on the evolution of the arthropod brain, vision, and head structure. The results were announced in the paper, “A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation,” published in the journal Current Biology.
It’s what’s inside Stanleycaris’ head that has the researchers most excited. In 84 of the fossils, the remains of the brain and nerves are still preserved after 506 million years.
“While fossilized brains from the Cambrian Period aren’t new, this discovery stands out for the astonishing quality of preservation and the large number of specimens,” said Joseph Moysiuk, lead author of the research and a University of Toronto (U of T) Ph.D. Candidate in Ecology and Evolutionary Biology, based at the Royal Ontario Museum. “We can even make out fine details such as visual processing centers serving the large eyes and traces of nerves entering the appendages. The details are so clear it’s as if we were looking at an animal that died yesterday.”
The new fossils show that the brain of Stanleycaris was composed of two segments, the protocerebrum and deutocerebrum, connected with the eyes and frontal claws, respectively. “We conclude that a two-segmented head and brain has deep roots in the arthropod lineage and that its evolution likely preceded the three-segmented brain that characterizes all living members of this diverse animal phylum,” added Moysiuk.
In present day arthropods like insects, the brain consists of protocerebrum, deutocerebrum, and tritocerebrum. While the difference of a segment may not sound game-changing, it in fact has radical scientific implications. Since repeated copies of many arthropod organs can be found in their segmented bodies, figuring out how segments line up between different species is key to understanding how these structures diversified across the group. “These fossils are like a Rosetta Stone, helping to link traits in radiodonts and other early fossil arthropods with their counterparts in surviving groups.”
In addition to its pair of stalked eyes, Stanleycaris possessed a large central eye at the front of its head, a feature never before noticed in a radiodont. “The presence of a huge third eye in Stanleycaris was unexpected. It emphasizes that these animals were even more bizarre-looking than we thought, but also shows us that the earliest arthropods had already evolved a variety of complex visual systems like many of their modern kin,” said Dr. Jean-Bernard Caron, ROM’s Richard Ivey Curator of Invertebrate Paleontology, and Moysiuk’s Ph.D. supervisor. “Since most radiodonts are only known from scattered bits and pieces, this discovery is a crucial jump forward in understanding what they looked like and how they lived,” added Caron, who is also an Associate Professor at the U of T, in Ecology & Evolution and Earth Sciences.
In the Cambrian Period, radiodonts included some of the biggest animals around, with the famous “weird wonder” Anomalocaris reaching up to at least 1 meter in length. At no more than 20 cm long, Stanleycaris was small for its group, but at a time when most animals grew no bigger than a human finger, it would have been an impressive predator. Stanleycaris’ sophisticated sensory and nervous systems would have enabled it to efficiently pick out small prey in the gloom.
With large compound eyes, a formidable-looking circular mouth lined with teeth, frontal claws with an impressive array of spines, and a flexible, segmented body with a series of swimming flaps along its sides, Stanleycaris would have been the stuff of nightmares for any small bottom dweller unfortunate enough to cross its path.
-
Reconstruction of Stanleycaris hirpex. Credit: Art by Sabrina Cappelli © Royal Ontario Museum
-
Fossil specimen of Stanleycaris hirpex. Dark material inside the head is the remains of nervous tissue, specimen ROMIP 65674.2. Credit: Jean-Bernard Caron © Royal Ontario Museum
About the Burgess Shale
For this research, Moysiuk and Caron studied a previously unpublished collection of 268 specimens of Stanleycaris. The fossils were primarily collected in the 1980s and 90s from rock layers above the famous Walcott Quarry site of the Burgess Shale in Yoho National Park, B.C., Canada, and are part of the extensive collection of Burgess Shale fossils housed at ROM.
-
Paper summary, showing the interpretation of the nervous system from fossils of Stanleycaris and implications for understanding the evolution of the arthropod brain. The brain is represented in red and the nerve cords in purple. Credit: Jean-Bernard Caron © Royal Ontario Museum
-
Fossil specimen of Stanleycaris hirpex. Dark material inside the head is the remains of nervous tissue, specimen ROMIP 65674.1. Credit: Jean-Bernard Caron © Royal Ontario Museum
The Burgess Shale fossil sites are located within Yoho and Kootenay National Parks and are managed by Parks Canada. Parks Canada is proud to work with leading scientific researchers to expand knowledge and understanding of this key period of earth history and to share these sites with the world through award-winning guided hikes. The Burgess Shale was designated a UNESCO World Heritage Site in 1980 due to its outstanding universal value and is now part of the larger Canadian Rocky Mountain Parks World Heritage Site.
Fossils of Stanleycaris can be seen by the public in the new Burgess Shale fossil display in the Willner Madge Gallery, Dawn of Life at ROM.
Massive new animal species discovered in half-billion-year-old Burgess Shale
More information:
Joseph Moysiuk, A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation, Current Biology (2022). DOI: 10.1016/j.cub.2022.06.027. www.cell.com/current-biology/f … 0960-9822(22)00986-1
Joseph Moysiuk, A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation, Current Biology (2022). DOI: 10.1016/j.cub.2022.06.027. www.cell.com/current-biology/f … 0960-9822(22)00986-1
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Covid vaccines: how can immune imprinting help experts to rethink jabs?
A surge in Covid-19 hospital admissions driven by the BA.5 subvariant of Omicron, accompanied by the inability of vaccines to prevent reinfection, has prompted health policymakers to rethink their approach to boosters.
US regulators last week recommended changing the design of vaccines to produce a new booster targeting Omicron — the first change to the make-up of shots since their introduction in late 2020. Research into immune imprinting, whereby exposure to the virus via either infection or vaccination determines an individual’s level of protection, is now driving the debate over the make-up of Covid-19 vaccines.
Immunologists say that, more than two years into the coronavirus pandemic, people have acquired very different types of immunity to the Sars-Cov-2 virus, depending on which strain or combination of strains they have been exposed to — leading to big differences in Covid-19 outcomes between individuals and countries.
“The effect is more nuanced than ‘more times you have it, less protection you get’,” said professor Danny Altmann of Imperial College London, who is investigating the phenomenon with colleagues. “It’s more helpful to consider it as progressive fine-tuning of a huge repertoire. Sometimes this will be beneficial for the next wave, sometimes not.”
What is immune imprinting?
After someone encounters a virus for the first time, through infection or vaccination, the immune system remembers its initial response in a way that usually weakens the response to future variants of the same pathogen but may sometimes strengthen it. Proteins on the “spike”, which the virus uses to bind with human cells, play a key role.
“Our first encounter with the spike antigen, either through infection or vaccination, shapes our subsequent pattern of immunity through immune imprinting,” said professor Rosemary Boyton of Imperial College.
The pattern has been observed for many years in flu and dengue virus, when it was usually called original antigenic sin. Studies are now demonstrating that it applies to Sars-Cov-2 too, although the effects are hard to pin down, according to Altmann, who prefers the term “immune imprinting” to the biblical connotations of original sin.
A study of 700 UK healthcare workers by the Imperial team, published last month in the journal Science, found that Omicron infection had little or no beneficial effect of boosting any part of the immune system — antibodies, B-cells or T-cells — among people who had been imprinted with earlier Sars-Cov-2 variants.
“Omicron is far from a benign natural booster of vaccine immunity, as we might have thought, but it is an especially stealthy immune evader,” said Altmann.
Vaccines currently in use were designed to target the virus as it first emerged from Wuhan, China, more than two years ago. They retain high protection against severe disease and hospital admissions but their efficacy against transmission and mild infection wanes quickly, especially against Omicron.
Understanding the effect of immune imprinting will help health officials to decide which vaccines to use in future booster campaigns. Boyton said immune imprinting has “important implications for future-proofing vaccine design and dosing strategies”.
Does immune imprinting help to explain breakthrough infections?
Most people in the industrialised world have been infected or vaccinated against Covid — or both. England’s Schools Infection Survey, run by the London School of Hygiene and Tropical Medicine, last week released data showing that 99 per cent of secondary schoolchildren tested positive for Covid antibodies from natural infection.
By this stage of the pandemic, the vast majority of Covid cases are reinfections in people whose immune defences acquired from vaccines or earlier infections do not hold up against Omicron BA.4 and BA.5.
Nor are these “breakthrough” infections necessarily as mild as many people believe, said Ziyad Al-Aly, a clinical epidemiologist at Washington University in St Louis. He analysed the health records of 34,000 people with breakthrough Covid infections in the database of the US veterans administration, which provides healthcare services for retired soldiers. The cumulative risk of serious damage to heart, brain and lungs rose significantly with each repeated infection.
In another study, Al-Aly and colleagues found that, while vaccines are good at preventing acute Covid-19, they were just 15 per cent effective at preventing long Covid, which is defined as suffering symptoms for 12 weeks or more after a Covid-19 diagnosis. “Getting Covid, even among vaccinated people, seems almost unavoidable nowadays,” he said.
Has immune imprinting influenced vaccine debates?
Some anti-vaxxers have enlisted immune imprinting in their arguments, on the grounds that vaccines become less effective as the virus evolves — an objection that immunologists reject forcefully.
“While our latest findings highlight clear concerns about the nature of Omicron infection, vaccination remains effective against severe disease,” said Altmann. “Those who are eligible to receive a booster should be encouraged to do so.”
Professor Christian Drosten, a leading German virologist, said in an interview with Der Spiegel that extending the interval between jabs could help reduce the impact of immune imprinting.
“I suspect the effect [of vaccination] will get better, the greater the interval from the previous vaccination,” he said. “[But] it is not yet known how long the interval between vaccinations should actually be.”
How has differing immunity affected decisions on vaccines?
The World Health Organization last month said Omicron-based jabs may be beneficial as boosters because they would broaden protection against different variants.
And, on Tuesday, the US Food and Drug Administration advisory committee voted 19 to two in favour of incorporating genetic material from Omicron into new booster jabs.
“We’re trying to use every last ounce of what we can from predictive modelling, and from the data that is emerging, to try to get ahead of a virus that has been very crafty,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.
On Thursday, the FDA recommended including a component of the BA.4/BA.5 Omicron subvariants in a new shot for autumn booster campaigns. But the agency has not advised a change to the existing vaccine for first doses.
Moderna and BioNTech/Pfizer, the leading manufacturers of mRNA vaccines, have submitted laboratory data showing that their latest versions, targeted at Omicron, produce a potent antibody response against BA.4 and BA.5. But some immunologists remain uncertain whether they will be more effective than receiving another dose of the original Wuhan vaccine.
“Due to immune imprinting, patterns of anti-spike immunity in different people and populations have become heterogeneous, complex and unpredictable,” said Boyton. “This makes the argument for moving forward in a careful, considered and evidence-based way.”
“The challenge for next-generation Covid vaccines is to design vaccines that broaden the immune response to protect against future variants of concern.”
You may want to rethink your summer travel plans. Here’s why.
Anyone looking for a summer getaway is likely to find themselves caught in a chaotic web of canceled flights, pricey rental cars or fully booked hotels. The prospect of getting from point A to point B without an expensive headache may seem all but impossible.
Consider this: On Wednesday, 639 flights within, into, or out of the United States were canceled, and 5,837 were delayed, according to flight tracking data from FlightAware.
Delta Air Lines alone has trimmed about 100 flights a day from its schedule in July to “minimize disruptions” and has issued a waiver for July 4 travelers as it braces for passenger volumes “not seen since before the pandemic.”
Renting a car — if you can find one — will likely cost you more than years past. And hotel prices are climbing nationwide too. So much for relaxation.
What’s going on?
Your summer travel woes (probably) aren’t your fault. In the sky, airlines have significantly fewer employees, especially pilots, than they did before the pandemic. And on the road, a shortage of available vehicles has pushed rental car prices up double digits.
Add in record high inflation with a remarkable demand for leisure travel and you have a recipe for trouble.
A lot of this turbulence can be traced back to Covid-19.
It starts with demand. Airlines and hotels are forecasting record travel this summer as Americans who delayed trips during the pandemic return to vacationing.
Demand meets short staffing. Though airlines received $54 billion in federal assistance during Covid’s peak to avoid involuntary layoffs, they have fewer employees after offering buyouts and early retirement packages to trim staff and save money.
Short staffing creates problems. As a result, operations can quickly fall apart when there’s bad weather, understaffed air traffic control centers or sick staff.
Then there’s inflation. The Consumer Price Index, the government’s leading inflation measure, estimates that overall fares were up 37.8% in May compared to the previous year, and up 21.7% compared to May of 2019, before the pandemic.
Remember, in the throes of the outbreak, the Federal Reserve implemented emergency stimulus measures to keep financial markets from tanking. The central bank slashed interest rates to near zero and began pumping tens of billions of dollars every month into the markets by buying up corporate debt.
In doing so, the bank likely prevented a financial meltdown. But keeping those easy money policies in place has also fueled inflation, which is why your airline ticket costs a lot more than it used to.
Rental cars also have a pandemic problem. During the height of the pandemic, the industry sold off more than a half a million cars, about a third of their combined fleets, just to generate cash they needed to survive the crisis. Following a year of deep losses, rental car companies have had trouble rebuilding their fleets to meet demand, resulting in exorbitantly high prices before you even fill up the tank.
Hotels, too. You won’t feel much relief when you reach your destination either. Remember the issue of pent-up travel demand? That’s crashing into a limited number of places to stay and resulting in some eye-popping prices.
The rate for an average hotel room is 23% higher than last year, according to AAA.
What’s the Biden administration doing?
Earlier this month, Transportation Secretary Pete Buttigieg urged airline executives in a private conversation to review their flight schedules and take other steps to soften the impact of summer flight cancellations, a source familiar with the call told CNN’s Gregory Wallace.
The source said Buttigieg asked CEOs to talk through plans to prevent and respond to disruptions over the July Fourth holiday weekend and beyond.
What are airlines saying?
US airlines want you to know they’re trying. Airlines for America, the group representing major US airlines, told CNN in a statement Thursday that it is making “every effort to help ensure smooth travel this weekend.”
“U.S. airlines are navigating a range of challenges — including weather and staffing at the carrier and federal government level — and making every effort to help ensure smooth travel this weekend and year-round. As always, we are working closely and collaboratively with the federal government to address challenges, including inclement weather, so adjustments to schedules can be made and carriers can communicate with travelers as early as possible,” the statement said.
The group’s airline members are taking different approaches to reducing summer flight disruptions, including cutting the number of flights and allowing passengers to rebook without fees for non-peak periods.
Still, critics say airlines should have anticipated a lot of these issues ahead of the summer travel season.
How long will this last?
Read this piece by aviation journalist John Walton.
He writes: In almost every case, the problem is that too many experienced people were let go during the pandemic — either laid off or given a voluntary out — and that airlines, airports, and other key parts of the aviation system have not hired and qualified enough people to replace them.
That qualification point is important. As airlines and airports know all too well, there’s a whole process involved to get someone the kind of security pass that allows them to work on an airplane or at an airport gate.
Put differently, travel is going to be difficult for a while.
How can you prepare?
If you do have summer travel plans, you’re not doomed. The CNN travel team pulled together practical tips that will help you reach your destination if it involves flying.
The earlier the better. Taking a flight that departs early in the day helps to avoid the cascading effect of delays and cancellations. Bad weather is also more likely to affect later flights.
Leave cushion time for can’t-miss events. Don’t travel on the day of an important event such as a wedding. Plan to arrive at least one day early.
Ask for a hotel voucher if your flight is canceled. If you can’t get on a flight the same day, it’s worth asking for meal or hotel vouchers. In many cases, such as weather events, airlines aren’t required to provide them, but it’s worth asking.
Most importantly, stay considerate. Don’t take your frustration out on customer service employees. They aren’t making the operations decisions.
CNN’s Gregory Wallace, Chuck Johnston and Ramishah Maruf, contributed to this report.