Science
A Fossil Mystery, Solved by a Spin
These fossilized “blobs” were a puzzle 310 million years old.
Paleontologists decided that they were odd jellyfish named Essexella asherae. But the creature’s anatomy was unlike that of any living jellyfish.
Roy Plotnick, a paleontologist at the University of Illinois Chicago, turned an Essexella specimen upside down while doing research.
Immediately, the seemingly amorphous blob’s true identity began to take shape.
What scientists thought was a free-floating jellyfish instead revealed itself to be another ocean creature altogether.
Essexella fossils date back to the Carboniferous period, when northern parts of Illinois hovered just above the equator. A local river delta fed into the sea, creating a network of brackish wetlands home to sea scorpions, centipedes and early amphibians. Many of these creatures were buried by mudslides, which protected their remains from scavengers and decay. In the 19th century, coal miners began excavating an area, known as Mazon Creek, for fuel, and the fossils turned up in their spoil heaps.
Collectors have been finding the remains of these critters in the Mazon Creek fossil beds for more than a century. Most of the fossils are entombed in ironstone nodules. Cracking these concretions reveals the imprints of soft-bodied animals that resemble bulge-eyed aliens. In the 1950s, a local collector named Francis Tully discovered the imprint of a torpedo-shaped creature with a nozzlelike mouth. The taxonomic identity of the “Tully monster” has perplexed researchers ever since.
Essexella was similarly perplexing. Nondescript fossils turned up by the thousands at Mazon Creek, and they were often sold at local flea markets, or even discarded.
Scientists published the first detailed scientific description of the blobs in 1979. Essexella fossils are composed of two structures — a textured, barrel-shaped region and a smooth bulb. Researchers posited that the textured area represented a skirtlike curtain that wrapped around jellyfish tentacles. The rounded region was the jellyfish bell.
But as time passed, this description struck many researchers as odd.
“We were really shoehorning it to fit the jellyfish model,” Dr. Plotnick said.
No living jellyfish have curtains around their tentacles. Such a curtain would make swimming and feeding cumbersome. The uniform shape of the blob fossils also perplexed Dr. Plotnick. “If it was a jellyfish that fell on the seafloor, it would just splatter out in all directions like an old string mop on the floor,” he said.
Dr. Plotnick tested some other hypotheses to explain the blobs — such as gelatinous, barrel-shaped critters called salps or colonial congregations of tiny creatures known as siphonophores — but each new identity failed to explain Essexella’s anomalous anatomy.
In late 2016, Dr. Plotnick and a colleague, James Hagadorn, a geologist at the Denver Museum of Nature and Science, investigated the motherlode of blobs. They were at the Field Museum in Chicago, a repository for Mazon Creek fossils that has the world’s largest Essexella collection. Most had been donated by amateur collectors who were too intrigued to leave the fossils in the scrap heap.
The scientists sifted through drawer after drawer of the splotchy specimens. They lined up several fossils to photograph and compare side by side on a table. One of the blobs caught Dr. Plotnick’s eye. As he rotated the fossil upside down, he was struck by the clarity that the change of perspective offered.
“It looked like the bottom of an anemone,” Dr. Plotnick said. He added, “That was one of only a few times I’ve actually had the classic eureka moment.”
Artist’s impressions of the anatomy of Essexella as an anemone. Marjorie Leggitt
As Dr. Plotnick brushed up on sea anemone anatomy, the ambiguous blobs came into focus. “All the things that bothered us about this being a jellyfish now makes sense,” he said.
Instead of being a jellyfish’s bell, the rounded region of the Essexella was an anemone’s burrowing base. The textured barrel was not a tentacle-enclosing curtain but the body of the anemone. Some specimens are preserved so well that the scientists could see the muscles that the anemone used to bend and contract.
Dr. Plotnick, Dr. Hagadorn and their team redescribed Essexella as an ancient anemone last year in the journal Papers in Palaeontology. Because of their soft bodies, ancient anemone species are mostly known from only a handful of poorly preserved fossils. With thousands of relatively well-preserved Essexella specimens, this once puzzling species is now the best-known anemone in the fossil record. Dr. Plotnick posits that these animals once lined the floor of the Mazon Creek estuary.
This isn’t the only time that paleontologists have flipped the scientific script to clarify the identity of a bizarre fossil. Reconstructing any ancient animal is tricky. After millions of years in the ground, fossils have been warped and weathered, crushed and scattered and stamped flat onto slabs of stone.
Sometimes, a fossil’s preservation alone is enough to disorient researchers. For decades, paleontologists were stumped by why armor-clad dinosaurs called Ankylosaurs were almost always fossilized upside down. In 2018, a team posited that the heavily armored animals often went belly up because of bloating as their carcasses floated out to sea.
And then there are the evolutionary oddballs that are difficult to decipher no matter the orientation of their fossils. In 1869, the paleontologist Edward Drinker Cope mistakenly placed the skull of an Elasmosaurus, a marine reptile, at the end of the creature’s tail instead of its elongated neck. Othniel Charles Marsh, another paleontologist, seized on Cope’s error, igniting a rivalry that would fester into the so-called Bone War.
Researchers couldn’t make heads or tails of Hallucigenia when it was found in rock.
The Natural History Museum / Alamy The head was the tail and the tail was the head on the wormy creature.
De Agostini via Getty Images
Even weirder was Hallucigenia. For decades, researchers could not make heads or tails of the creature, a worm covered in tentacles and stiltlike spines. Then they realized that its head was really its tail, and vice versa. “That was fun and not a mere detail,” said Jean-Bernard Caron, who is a paleontologist at the Royal Ontario Museum and a co-author of a study in 2015 that determined a bulb on one end of the Hallucigenia was the creature’s head. Better-preserved fossils of a related animal in China also revealed that Hallucigenia, like Essexella, was originally reconstructed upside down.
“Clearly Hallucigenia has seen many flips,” Dr. Caron said.
While Dr. Caron’s work helped straighten out Hallucigenia, a recent paper upends his 2012 description of Pikaia, an enigmatic wormlike creature from the Burgess Shale in Canada that was purported to be an early forerunner to vertebrates. The new study suggests that a mysterious tubelike organ that researchers thought ran along Pikaia’s back (and may have been an early nerve cord) is actually the animal’s gut cavity, running along its belly.
“The animal is now on its head!” Dr. Caron said. Yet another fossilized creature got a new story when it turned over.
Science
Tuberculosis outbreak reported at Catholic high school in Bay Area. Cases statewide are climbing
Public health officials in Northern California are investigating a tuberculosis outbreak, identifying more than 50 cases at a private Catholic high school and ordering those who are infected to stay home. The outbreak comes as tuberculosis cases have been on the rise statewide since 2023.
The San Francisco Department of Public Health issued a health advisory last week after identifying three active cases and 50 latent cases of tuberculosis at Archbishop Riordan High School in San Francisco. The disease attacks the lungs and remains in the body for years before becoming potentially deadly.
A person with active TB can develop symptoms and is infectious; a person with a latent tuberculosis infection cannot spread the bacteria to others and doesn’t feel sick. However, a person with a latent TB infection is at risk of developing the disease anytime.
The three cases of active TB have been diagnosed at the school since November, according to public health officials. The additional cases of latent TB have been identified in people within the school community.
Archbishop Riordan High School, which recently transitioned from 70 years of exclusively admitting male students to becoming co-ed in 2020, did not immediately respond to the The Times’ request for comment.
School officials told NBC Bay Area news that in-person classes had been canceled and would resume Feb. 9, with hybrid learning in place until Feb. 20. Students who test negative for tuberculosis will be allowed to return to campus even after hybrid learning commences.
Officials with the San Francisco Department of Public Health said the risk to the general population was low. Health officials are currently focused on the high school community.
How serious is a TB diagnosis?
Active TB disease is treatable and curable with appropriate antibiotics if it is identified promptly; some cases require hospitalization. But the percentage of people who have died from the disease is increasing significantly, officials said.
In 2010, 8.4% of Californians with TB died, according to the California Department of Public Health. In 2022, 14% of people in the state with TB died, the highest rate since 1995. Of those who died, 22% died before receiving TB treatment.
The Centers for Disease Control and Prevention estimated that up to 13 million people nationwide live with latent TB.
How does California’s TB rate compare to the country?
Public health officials reported that California’s annual TB incidence rate was 5.4 cases per 100,000 people last year, nearly double the national incidence rate of 3.0 per 100,000 in 2023.
In 2024, 2,109 California residents were reported to have TB compared to 2,114 in 2023 — the latter was about the same as the total number of cases reported in 2019, according to the state Department of Public Health.
The number of TB cases in the state has remained consistent from 2,000 to 2,200 cases since 2012, except during the COVID-19 pandemic from 2020 to 2022.
California’s high TB rates could be caused by a large portion of the population traveling to areas where TB is endemic, said Dr. Shruti Gohil, associate medical director for UCI Health Epidemiology and Infection Prevention.
Nationally, the rates of TB cases have increased in the years following the COVID-19 pandemic, which “was in some ways anticipated,” said Gohil. The increasing number of TB cases nationwide could be due to a disruption in routine care during the pandemic and a boom in travel post-pandemic.
Routine screening is vital in catching latent TB, which can lie dormant in the body for decades. If the illness is identified, treatment could stop it from becoming active. This type of routine screening wasn’t accessible during the pandemic, when healthcare was limited to emergency or essential visits only, Gohil said.
When pandemic restrictions on travel were lifted, people started to travel again and visit areas where TB is endemic, including Asia, Europe and South America, she said.
To address the uptick in cases and suppress spread, Gov. Gavin Newsom signed Assembly Bill 2132 into law in 2024, which requires adult patients receiving primary care services to be offered tuberculosis screening if risk factors are identified. The law went into effect in 2025.
What is TB?
In the United States, tuberculosis is caused by a germ called Mycobacterium tuberculosis, which primarily affects the lungs and can impact other parts of the body such as the brain, kidneys and spine, according to the Centers for Disease Control and Prevention. If not treated properly, TB can be fatal.
TB is spread through the air when an infected person speaks, coughs or sings and a nearby person breathes in the germs.
When a person breathes in the TB germs, they settle in the lungs and can spread through the blood to other parts of the body.
The symptoms of active TB include:
- A cough that lasts three weeks or longer
- Chest pain
- Coughing up blood or phlegm
- Weakness or fatigue
- Weight loss
- Loss of appetite
- Chills
- Fever
- Night sweats
Generally, who is at risk of contracting TB?
Those at higher risk of contracting TB are people who have traveled outside the United States to places where TB rates are high including Asia, the Middle East, Africa, Eastern Europe and Latin America.
A person has an increased risk of getting TB if they live or work in such locations as hospitals, homeless shelters, correctional facilities and nursing homes, according to the CDC.
People with weakened immune systems caused by health conditions that include HIV infection, diabetes, silicosis and severe kidney disease have a higher risk of getting TB.
Others at higher risk of contracting the disease include babies and young children.
Science
Contributor: Animal testing slows medical progress. It wastes money. It’s wrong
I am living with ALS, or amyotrophic lateral sclerosis, often called Lou Gehrig’s disease. The average survival time after diagnosis is two to five years. I’m in year two.
When you have a disease like ALS, you learn how slowly medical research moves, and how often it fails the people it is supposed to save. You also learn how precious time is.
For decades, the dominant pathway for developing new drugs has relied on animal testing. Most of us grew up believing this was unavoidable: that laboratories full of caged animals were simply the price of medical progress. But experts have known for a long time that data tell a very different story.
The Los Angeles Times reported in 2017: “Roughly 90% of drugs that succeed in animal tests ultimately fail in people, after hundreds of millions of dollars have already been spent.”
The Times editorial board summed it up in 2018: “Animal experiments are expensive, slow and frequently misleading — a major reason why so many drugs that appear promising in animals fail in human trials.”
Then there’s the ethical cost — confining, sickening and killing millions of animals each year for a system that fails 9 times out of 10. As Jane Goodall put it, “We have the choice to use alternatives to animal testing that are not cruel, not unethical, and often more effective.”
Despite overwhelming evidence and well-reasoned arguments against animal-based pipelines, they remain central to U.S. medical research. Funding agencies, academic medical centers, government labs, pharmaceutical companies and even professional societies have been painfully slow to move toward human- and technology-based approaches.
Yet medical journals are filled with successes involving organoids (mini-organs grown in a lab), induced pluripotent stem cells, organ-on-a-chip systems (tiny devices with human cells inside), AI-driven modeling and 3D-bioprinted human tissues. These tools are already transforming how we understand disease.
In ALS research, induced pluripotent stem cells have allowed scientists to grow motor neurons in a dish, using cells derived from actual patients. Researchers have learned how ALS-linked mutations damage those neurons, identified drug candidates that never appeared in animal models and even created personalized “test beds” for individual patients’ cells.
Human-centric pipelines can be dramatically faster. Some are reported to be up to 10 times quicker than animal-based approaches. AI-driven human biology simulations and digital “twins” can test thousands of drug candidates in silico, with a simulation. Some models achieve results hundreds, even thousands, of times faster than conventional animal testing.
For the 30 million Americans living with chronic or fatal diseases, these advances are tantalizing glimpses of a future in which we might not have to suffer and die while waiting for systems that don’t work.
So why aren’t these tools delivering drugs and therapies at scale right now?
The answer is institutional resistance, a force so powerful it can feel almost god-like. As Pulitzer Prize–winning columnist Kathleen Parker wrote in 2021, drug companies and the scientific community “likely will fight … just as they have in past years, if only because they don’t want to change how they do business.”
She reminds us that we’ve seen this before. During the AIDS crisis, activists pushed regulators to move promising drugs rapidly into human testing. Those efforts helped transform AIDS from a death sentence into a chronic condition. We also saw human-centered pipelines deliver COVID vaccines in a matter of months.
Which brings me, surprisingly, to Robert F. Kennedy Jr. In December, Kennedy told Fox News that leaders across the Department of Health and Human Services are “deeply committed to ending animal experimentation.” A department spokesperson later confirmed to CBS News that the agency is “prioritizing human-based research.”
Kennedy is right.
His directive to wind down animal testing is not anti-science. It is pro-patient, pro-ethics and pro-progress. For people like me, living on borrowed time, it is not just good policy, it is hope — and a potential lifeline.
The pressure to end animal testing and let humans step up isn’t new. But it’s getting new traction. The actor Eric Dane, profiled about his personal fight with ALS, speaks for many of us when he expresses his wish to contribute as a test subject: “Not to be overly morbid, but you know, if I’m going out, I’m gonna go out helping somebody.”
If I’m going out, I’d like to go out helping somebody, too.
Kevin J. Morrison is a San Francisco-based writer and ALS activist.
Science
A push to end a fractured approach to post-fire contamination removal
The patchwork efforts to identify and safely remove contamination left by the 2025 Eaton and Palisades fires has been akin to the Wild West.
Experts have given conflicting guidance on best practices. Shortly after the fires, the federal government suddenly refused to adhere to California’s decades-old post-fire soil-testing policy; California later considered following suit.
Meanwhile, insurance companies have resisted remediation practices widely recommended by scientists for still-standing homes.
A new bill introduced this week by state Assemblymember John Harabedian (D-Pasadena) aims to change that by creating statewide science-based standards for the testing and removal of contamination deposited by wildfires — specifically within still-standing homes, workplaces and schools, and in the soil around those structures.
“In a state where we’ve had a number of different wildfires that have happened in urban and suburban areas, I was shocked that we didn’t have a black-and-white standard and protocol that would lay out a uniform post-fire safety standard for when a home is habitable again,” Harabedian said.
The bill, AB 1642, would task the state’s Department of Toxic Substances Control with creating standards by July 1, 2027. The standards would only serve as guidance — not requirements — but even that would be helpful, advocates say.
“Guidance, advisories — those are extremely helpful for families that are trying to return home safely,” said Nicole Maccalla, who leads data science efforts with Eaton Fire Residents United, a grassroots organization addressing contamination in still-standing homes. “Right now, there’s nothing … which means that insurance companies are the decision-makers. And they don’t necessarily prioritize human health. They’re running a business.”
Maccalla supports tasking DTSC with determining what levels of contamination pose an unacceptable health risk, though she does want the state to convene independent experts including physicians, exposure scientists and remediation professionals to address the best testing procedures and cleanup techniques.
Harabedian said the details are still being worked out.
“What’s clear from my standpoint, is, let’s let the public health experts and the science and the scientists actually dictate what the proper standards and protocol is,” Harabedian said. “Not bureaucrats and definitely not insurance companies.”
For many residents with still-standing homes that were blanketed in toxic soot and ash, clear guidance on how to restore their homes to safe conditions would be a much welcome relief.
Insurance companies, environmental health academics, and professionals focused on addressing indoor environmental hazards have all disagreed on the necessary steps to restore homes, creating confusion for survivors.
Insurance companies and survivors have routinely fought over who is responsible for the costs of contamination testing. Residents have also said their insurers have pushed back on paying for the replacement of assets like mattresses that can absorb contamination, and any restoration work beyond a deep clean, such as replacing contaminated wall insulation.
Scientists and remediation professionals have clashed over which contaminants homeowners ought to test for after a fire. Just last week, researchers hotly debated the thoroughness of the contamination testing at Palisades Charter High School’s campus. The school district decided it was safe for students to return; in-person classes began Tuesday.
Harabedian hopes the new guidelines could solidify the state’s long-standing policy to conduct comprehensive, post-fire soil testing.
Not long after the federal government refused to adhere to the state’s soil testing policy, Nancy Ward, the former director of the California Governor’s Office of Emergency Services, had privately contemplated ending state funding for post-fire soil testing as well, according to an internal memo obtained by The Times.
“That debate, internally, should have never happened,” Harabedian said. “Obviously, if we have statewide standards that say, ‘This is what you do in this situation,’ then there is no debate.”
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