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A Fossil Mystery, Solved by a Spin

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A Fossil Mystery, Solved by a Spin
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These fossilized “blobs” were a puzzle 310 million years old.

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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.

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Immediately, the seemingly amorphous blob’s true identity began to take shape.

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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.

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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.

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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.

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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.

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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

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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.

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“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.

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What’s in a Name? For These Snails, Legal Protection

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What’s in a Name? For These Snails, Legal Protection

The sun had barely risen over the Pacific Ocean when a small motorboat carrying a team of Indigenous artisans and Mexican biologists dropped anchor in a rocky cove near Bahías de Huatulco.

Mauro Habacuc Avendaño Luis, one of the craftsmen, was the first to wade to shore. With an agility belying his age, he struck out over the boulders exposed by low tide. Crouching on a slippery ledge pounded by surf, he reached inside a crevice between two rocks. There, lodged among the urchins, was a snail with a knobby gray shell the size of a walnut. The sight might not dazzle tourists who travel here to see humpback whales, but for Mr. Avendaño, 85, these drab little mollusks represent a way of life.

Marine snails in the genus Plicopurpura are sacred to the Mixtec people of Pinotepa de Don Luis, a small town in southwestern Oaxaca. Men like Mr. Avendaño have been sustainably “milking” them for radiant purple dye for at least 1,500 years. The color suffuses Mixtec textiles and spiritual beliefs. Called tixinda, it symbolizes fertility and death, as well as mythic ties between lunar cycles, women and the sea.

The future of these traditions — and the fate of the snails — are uncertain. The mollusks are subject to intense poaching pressure despite federal protections intended to protect them. Fishermen break them (and the other mollusks they eat) open and sell the meat to local restaurants. Tourists who comb the beaches pluck snails off the rocks and toss them aside.

A severe earthquake in 2020 thrust formerly submerged parts of their habitat above sea level, fatally tossing other mollusks in the snail’s food web to the air, and making once inaccessible places more available to poachers.

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Decades ago, dense clusters of snails the size of doorknobs were easy to find, according to Mr. Avendaño. “Full of snails,” he said, sweeping a calloused, violet-stained hand across the coves. Now, most of the snails he finds are small, just over an inch, and yield only a few milliliters of dye.

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Video: This Parrot Has No Beak, But Is at the Top of the Pecking Order

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Video: This Parrot Has No Beak, But Is at the Top of the Pecking Order

new video loaded: This Parrot Has No Beak, But Is at the Top of the Pecking Order

Bruce, a disabled kea parrot, is missing his top beak. The bird uses tools to keep himself healthy and developed a jousting technique that has made him the alpha male of his group.

By Meg Felling and Carl Zimmer

April 20, 2026

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Contributor: Focus on the real causes of the shortage in hormone treatments

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Contributor: Focus on the real causes of the shortage in hormone treatments

For months now, menopausal women across the U.S. have been unable to fill prescriptions for the estradiol patch, a long-established and safe hormone treatment. The news media has whipped up a frenzy over this scarcity, warning of a long-lasting nationwide shortage. The problem is real — but the explanations in the media coverage miss the mark. Real solutions depend on an accurate understanding of the causes.

Reporters, pharmaceutical companies and even some doctors have blamed women for causing the shortage, saying they were inspired by a “menopause moment” that has driven unprecedented demand. Such framing does a dangerous disservice to essential health advocacy.

In this narrative, there has been unprecedented demand, and it is explained in part by the Food and Drug Administration’s recent removal of the “black-box warning” from estradiol patches’ packaging. That inaccurate (and, quite frankly, terrifying) label had been required since a 2002 announcement overstated the link between certain menopause hormone treatments and breast cancer. Right-sizing and rewording the warning was long overdue. But the trouble with this narrative is that even after the black-box warning was removed, there has not been unprecedented demand.

Around 40% of menopausal women were prescribed hormone treatments in some form before the 2002 announcement. Use plummeted in its aftermath, dipping to less than 5% in 2020 and just 1.8% in 2024. According to the most recent data, the number has now settled back at the 5% mark. Unprecedented? Hardly. Modest at best.

Nor is estradiol a new or complex drug; the patch formulation has existed for decades, and generic versions are widely manufactured. There is no exotic ingredient, no rare supply chain dependency, no fluke that explains why women are suddenly being told their pharmacy is out of stock month after month.

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The story is far more an indictment of the broken insurance industry: market concentration, perverse incentives and the consequences of allowing insurance companies to own the pharmacy benefit managers that effectively control drug access for the majority of users. Three companies — CVS Caremark, Express Scripts and OptumRx — manage 79% of all prescription drug claims in the United States. Those companies are wholly owned subsidiaries of three insurance behemoths: CVS Health, Cigna and UnitedHealth Group, respectively. This means that the same corporation that sells you your insurance plan also decides which drugs get covered, at what price, and whether your pharmacy can stock them. This is called vertical integration. In another era, we might have called it a cartel. The resulting problems are not unique to hormone treatments; they have affected widely used medications including blood thinners, inhalers and antibiotics. When a low-cost generic such as estradiol — a medication with no blockbuster profit margins and no patent protection — runs into friction in this system, the friction is not random. It is structural. Every decision in that chain is filtered through the same corporate profit motive. And when the drug in question is an off-patent estradiol patch that has negligible profit margins because of generic competition but requires logistical investment to keep consistently in stock? The math on “how much does this company care about ensuring access” is not complicated.

Unfortunately, there is little financial incentive to ensure smooth, consistent access. There is, however, significant financial incentive to steer patients toward branded alternatives, or simply to let supply tighten — because the companies aren’t losing much profit if sales of that product dwindle. This is not a conspiracy theory: The Federal Trade Commission noted this dynamic in a report that documented how pharmacy benefit managers’ practices inflate costs, reduce competition and harm patient access, particularly for independent pharmacies and for generic drugs.

Any claim that the estradiol patch shortage is meaningfully caused by more women now demanding hormone treatments is a distraction. It is also misogyny, pure and simple, to imply that the solution to the shortage is for women’s health advocates to dial it down and for women to temper their expectations. The scarcity of estradiol patches is the outcome of a broken system refusing to provide adequate supply.

Meanwhile, there are a few strategies to cope.

  • Ask your prescriber about alternatives. Estradiol is available in multiple formulations, including gel, spray, cream, oral tablet, vaginal ring and weekly transdermal patch, which is a different product from the twice-weekly patch and may be more consistently available depending on manufacturer and region.
  • Consider an online pharmacy. Many are doing a good job locating and filling these prescriptions from outside the pharmacy benefit manager system.
  • Call ahead. Patch shortages are inconsistent across regions and distributors. A call to pharmacies in your area, or a broader geographic radius if you’re able, can locate stock that your regular pharmacy doesn’t have.
  • Consider a compounding pharmacy. These sources can sometimes meet needs when commercially manufactured products are inaccessible. The hormones used are the same FDA-regulated bulk ingredients.

Beyond those Band-Aid solutions, more Americans need to fight for systemic change. The FTC report exists because Congress asked for it and committed to legislation that will address at least some of the problems. The FDA took action to change the labeling on estrogen in the face of citizen and medical experts’ pressure; it should do more now to demand transparency from patch manufacturers.

Most importantly, it is on all of us to call out the cracks in the current system. Instead of repeating “there’s a patch shortage” or a “surge in demand,” say that a shockingly small minority of menopausal women still even get hormonal treatments prescribed at all, and three drug companies control the vast majority of claims in this country. Those are the real problems that need real solutions.

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Jennifer Weiss-Wolf, the executive director of the Birnbaum Women’s Leadership Center at New York University School of Law, is the author of the forthcoming book When in Menopause: A User’s Manual & Citizen’s Guide. Suzanne Gilberg, an obstetrician and gynecologist in Los Angeles, is the author of “Menopause Bootcamp.”

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