Spiders may have originated in the ocean before adapting to live on land
The "exquisitely preserved" specimen supports the idea that these creatures swam before adapting to life on land, according to a study published Tuesday in Current Biology.
Researchers at the University of Arizona analyzed the fossilized brain of Mollisonia symmetrica, an extinct Cambrian-period species once thought to be an ancestor of horseshoe crabs. However, the study revealed that its neural structure more closely resembles that of modern spiders and their relatives, suggesting a closer evolutionary link to arachnids than previously believed.
The front part of Mollisonia's body, called the prosoma, has a radiating pattern of nerve clusters that control five pairs of appendages. Additionally, its unsegmented brain sends short nerves to a pair of pincer-like 'claws,' resembling the fangs found in spiders and other arachnids.
The key feature identifying the fossil as an early arachnid is its brain's unique organization, which is the reverse of the front-to-back arrangement seen in modern crustaceans, insects, centipedes and horseshoe crabs, researchers said.
In a statement, Nick Strausfeld, lead author and professor at the University of Arizona, said the fossil's brain appears "flipped backwards," similar to modern spiders.
This back-to-front brain arrangement may be a key evolutionary adaptation, providing neural shortcuts that enhance movement control.
According to the study, this discovery questions the common belief that diversification happened only after a common ancestor transitioned to land. Earlier fossil evidence suggested that arachnids lived and evolved solely on land.
"It is still vigorously debated where and when arachnids first appeared, and what kind of chelicerates were their ancestors, and whether these were marine or semi-aquatic like horseshoe crabs," Strausfeld said.
As they adapted to life on land, Mollisonia-like arachnids likely fed on early insects and millipedes. These early arachnids may have also influenced the evolution of insect wings, an important defense mechanism.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Spectator
26-07-2025
- Spectator
Is this CS Lewis' most prescient work?
It's been 80 years since CS Lewis' remarkably prescient, That Hideous Strength, was published. The final book in a sci-fi trilogy, the novel recounts the battle for the soul of humanity in the heart of England. Even in 1945, George Orwell saw that: 'Plenty of people in our age do entertain the monstrous dreams of power that Mr Lewis attributes to his characters [the NICE scientists], and we are within sight of the time when such dreams will be realisable.' Little did he realise how soon his fears would play out. That Hideous Strength focuses around the National Institute of Coordinated Experiments (NICE), which aims to bring Britain under the rule of Science, beginning the process of transforming the human race into an inorganic species governed by a single, immortal leader. 'The human race is to become all Technocracy,' NICE high-up Professor Augustus Frost explains to recruit Mark Studdock. The plans include the sterilisation and selective breeding of the population, with indoctrination achieved through biochemical conditioning and the 'direct manipulation of the brain'. Ultimately, organic life is to be abolished: the new humans will be formed of chemicals and live on a 'clean' planet divested of vegetation. Crucially, without sex, man 'will finally become governable'. Eighty years on, the story reads like a fictional exploration of transhumanism and current technologies, from chips in the brain to global digital systems for identification and travel. A mysterious figure – part Arthurian, part Christ-like – leads the fight for an alternative future rooted in spiritual enlightenment and a wholesome kind of Englishness. Like The Chronicles of Narnia, That Hideous Strength is a classic tale of Good vs Evil but, as its subtitle A Modern Fairy-Tale for Grown-Ups suggests, it's also a sober exploration of the direction 'scientific progress' is taking us. NICE leaders choose Edgestow as the place to begin the takeover, where the 'progressive element' of the nearby university makes for easy pickings. The fellows nod through the sale of some college land while the faculty serves as a 'recruiting office' for the institute. Their prize recruit is Mark, a 'sociologist who can write', to produce newspaper articles to persuade the British public that change is necessary. 'It's the educated reader who CAN be gulled,' explains Lord Feverstone, a figure working with both government and NICE. 'When did you meet a workman who believes the papers? He takes it for granted that they're all propaganda and skips the leading articles…But the educated public, the people who read the high-brow weeklies, don't need reconditioning. They're all right already. They'll believe anything.' Deception will only be needed in the early stages: 'Once the thing gets going we shan't have to bother about the great heart of the British public'. And sure enough, NICE's private police force are soon terrorising the people of Edgestow. The signs the takeover is well underway have a curiously contemporary ring. Edgestow is home to a new population of imported workmen, prices have risen and the hotels have somehow passed into hands of NICE. A dense fog blankets the heart of England. Riots are engineered to get the powers justified by a state of emergency. The propaganda aimed at the working man is successful: in the pubs the locals blame the Welsh and Irish for the state of things. Lured into NICE by the prospect of higher salary and status, corrupted by the need to please and belong, it takes the befuddled Mark a long time to understand what he's dealing with. Just as he finally realises his life is in danger, it emerges that NICE's aspirations are global. There is no point in attempting to flee to America, as the 'claws' of the institute are 'embedded in every country'. By this point, some readers will be nodding in wonderment at how Lewis, writing during the Second World War, could have foreseen our present situation with such accuracy. Others will see familiar plot elements as stemming from dystopian fiction's classic device of warning by way of exaggeration. Either way, the heart of the novel concerns choice. In the spiritual war playing out, a side must be taken and the last battle fought. There is no way to avoid confronting the 'hideous strength'. In this, the final book of the trilogy, it is ordinary English people who must make that choice. In the second, entitled Perelandra, Ransom, a venturesome Cambridge don who has travelled to Venus, is confronted with Unman, a kind of automated psychopath. Ransom attempts some typically English tactics: first talking his enemy, then ignoring him and finally running away. When Unman reappears, Ransom realises the only resolution is to kill him. But as a creature of dark, transhumanist forces, Unman cannot be destroyed by ordinary means. Ransom has to dig deep and it takes two goes, the first requiring physical courage and the second the psychological ability to face and overcome inner fears. On earth, the encounter with the hideous strengthpresents just two paths: follow the transhumanists or join The Resistance. Mark's wife Jane takes the latter path only after much hesitation and resisting the messages of her clairvoyant dreams. Lewis presents his heroine as a stereotypical woman of her times: hankering after independence while constrained by the conventional values of her society. Two moments of truth push Jane to join the community of the good based at a nearby manor house: her direct experience of evil when she is captured and tortured by NICE and her subsequent meeting with the community Director – a 'bright solar blend of king and lover and magician' – when she finds her world 'unmade'. Mark's moral journey is messier and more human. Even when confronted with the truth about NICE and offered sanctuary with The Resistance, he still can't quite make the right decision. Lewis captures the moral confusion of a weak character perfectly: 'he wanted to be perfectly safe and yet also very nonchalant and daring' while his mind was 'one fluid confusion of wounded vanity and jostling fears and shames'. All the while, Lewis studs the novel with details that convey the everyday quality of life on earth and the potential for goodness even in in times of evil. The horror of what is happening in Edgestow is counter-balanced with elements of English cosiness – just as in the depths of the Narnian winter, you can still have a good tea with Mr and Mrs Beaver. I won't ruin things with a spoiler – better to read the entire trilogy yourself. The reception of the book in 1945 may have been mixed, but this belated reviewer finds it brilliantly illuminating. That Hideous Strength has come into its time.
Daily Mail
25-07-2025
- Daily Mail
Discovery of ancient 'penis worm' in the Grand Canyon rewrites the origin story of life
Scientists have uncovered a strange, ancient creature in the Grand Canyon that could rewrite the origin of life. Researchers from Cambridge found hundreds of tiny remains of a 'penis worm' buried deep in 500-million-year-old rocks in canyon walls in Arizona, revealing that the region once held perfect conditions for life to rapidly evolve. The fossilized creature featured hairy teeth that turned its mouth inside out to catch food. This study challenged the long-held belief that early complex life only evolved in harsh, oxygen-starved places, as the newly found soft-bodied fossils were found in a calm, oxygen-rich sea, a setting where remains usually rot too fast to fossilize. Researchers said that the Grand Canyon site acted like a 'Goldilocks zone,' not too extreme, not too barren, offering just the right conditions for early life to grow, evolve, and leave a mark. Giovanni Mussini, a PhD student in Earth Sciences, University of Cambridge, UK, and the lead author of the study, said: 'This was the best real estate on Earth at the time.' 'You had enough food, enough light, and the perfect depth. That's where evolution really kicked into gear.' The findings support the theory of evolutionary escalation, the idea that species evolve not only in response to their environment, but also to gain an edge over competing species. The soft-bodied animal fossils were uncovered in a layer of mudstone called the Bright Angel Formation, where most of the canyon's Cambrian-era fossils have been found. Researchers suggested that the fossils date back to a time when most major animal groups were just beginning to appear on Earth. Back then, the Grand Canyon region sat near the equator and was covered by a shallow sea, roughly 130 to 165 feet deep, with high oxygen levels, and the water was rich in nutrients. Scientists believe photosynthetic microbes helped pump even more oxygen into the water, creating the perfect conditions for larger, more complex life to thrive. The team uncovered over 1,500 microscopic strange fossils, including prawns with filter-feeding limbs, mollusks with chains of teeth, and weird worms with long, branching mouthparts. Moreover, the study published in Science Advances focused on a specific group of fossils called small carbonaceous fossils, or SCFs. These are microscopic remains of animals that did not have shells or bones, so they almost never show up in the fossil record. But in this case, researchers said the muddy seafloor buried them and kept them safe, and this rare preservation led them to see incredible details including tiny molars in shrimp-like creatures and delicate tooth rows in mollusks. 'This is a completely new way to look at life from the Cambrian period,' Mussini said. 'We are seeing parts of animals that are almost never preserved,' he added. Researchers found a strange creature called Kraytdraco spectatus, or a penis worm. They also discovered 967 fossils out of the 1,539 fossils of this one type of worm. It had a flexible tube-like mouth lined with hundreds of teeth shaped like tiny brushes. They compared it to simple living worms, and found out that Kraytdraco was about one and half to four inches long. That made it one of the larger animals in its neighborhood, and probably one of the more dominant. They also found out, unlike predators that eat other animals, this worm was likely to scrape up debris and filter its food from soil. Its body was built for gathering and sorting food, a sign it had plenty of energy to grow elaborate tools. They said that these species have complex organs and features, which scientists believed evolved slowly and only in tough environments, but the new fossils rewrote the idea. Susannah Porter, a paleontologist at UC Santa Barbara, said: 'It's not unlike if we only had great fossil records from Antarctica… but then suddenly we find human fossils in New York City, where people actually flourished.' 'We now get to see different kinds of evolutionary pressures, not just it's freezing, it's really hot, there's not a lot of water,' Porter explained. Scientists are still trying to figure out what sparked the Cambrian explosion, when most major animal groups first appeared. The most widely accepted idea is that oxygen levels in Earth's atmosphere began to rise about 550 million years ago, said Erik Sperling, an associate professor at Stanford University. Sperling suggested that with more oxygen, animals could turn food into energy more efficiently, giving them the boost they needed to move, grow, and hunt. 'The (emergence of) predators kicked off these escalatory arms races, and then we basically got the explosion of different ways of doing business,' Sperling said. The Grand Canyon stretches 277 miles and plunges more than a mile deep. If even a small part of it contains this level of fossil preservation, scientists say it could become one of the most important sites for tracing the origins of complex life on Earth.
The Independent
25-07-2025
- The Independent
What the analysis of a 500-million-year-old fossil reveals about the origin of spiders
New research suggests spiders and other arachnids may have originated in the sea, based on analysis of a 500-million-year-old fossil. University of Arizona researchers studied the 'exquisitely preserved' brain of Mollisonia symmetrica, an extinct Cambrian-period species. The fossil's neural structure was found to resemble modern spiders and their relatives, rather than horseshoe crabs, as previously believed. A key feature identifying the fossil as an early arachnid is its unique brain organization, which appears 'flipped backwards' similar to modern spiders. This discovery challenges the common belief that arachnid diversification happened only after a common ancestor transitioned to land.
