Latest news with #UniversityOfArizona
Yahoo
3 days ago
- Science
- Yahoo
500-Million-Year-Old Fossil Suggests Ocean Origin For Spiders
The special brains of spiders may have started to evolve in the oceans, long before their ancestors crawled onto land. A fresh look at a 500-million-year-old fossil by researchers from the University of Arizona and Lycoming College in the US and King's College London has revealed remarkable similarities between the brains of extinct marine arthropods and modern-day arachnids. The discovery wades into controversial territory regarding the evolutionary origin of spiders and their relatives. Today, spiders, scorpions, mites, and ticks are virtually all terrestrial, and the prevailing view is that these arachnids evolved from a common, land-dwelling ancestor. Related: Where that ancestor came from is a whole other mystery. Arachnids on land are related to other 'chelicerates' in the ocean, like sea spiders and horseshoe crabs, but the fossil record is very patchy. "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," explains University of Arizona neuroscientist Nicholas Strausfeld. The transition from sea to land is a big step for a little creature, no matter how many legs it has. The oldest accepted remains of an arachnid are of a 430-million-year-old scorpion, a critter that lived on land. But new evidence suggests that arachnids as a whole may have started to diverge from other chelicerates long before that. On the outside, Mollisonia symmetrica may not look very 'spidery'. It kind of resembles a pillbug with a bunch of little legs, and previously, it was thought to be an ancestor of horseshoe crabs. Using light microscopy, researchers have now imaged the fossil's central nervous system and come across an unexpected find. The nervous system of Mollisonia doesn't resemble that of a horseshoe crab or even a crustacean or insect. Instead, the pattern of radiating neural centers was flipped backward, like that of an arachnid. "The arachnid brain is unlike any other brain on this planet," explains Strausfeld. In the Mollisonia fossil, the unique nervous system seems to innervate numerous legs, as well as two pincer-like mouth parts, where modern spiders now have fangs. "This is a major step in evolution, which appears to be exclusive to arachnids," says evolutionary neuroscientist Frank Hirth from King's College London. "Yet already in Mollisonia, we identified brain domains that correspond to living species… " That seems to be no coincidence. Upon further statistical analysis, Hirth and colleagues have found that arachnids probably didn't evolve similar structures to Mollisonia by accident; they were more likely inherited. If the team is right, that puts Mollisonia at the base of the arachnid lineage, making it a sister to horseshoe crabs and sea spiders. While still speculative, it's possible that the unique brain structure seen in the Mollisonia lineage helped its later successors survive on land. Neural 'shortcuts' to the legs and pincers, for instance, could make it easier to control and coordinate complex movements, like walking or weaving webs. "We might imagine that a Mollisonia-like arachnid also became adapted to terrestrial life making early insects and millipedes their daily diet," theorizes Strausfeld. Perhaps it was the earliest arachnids on land that first drove insects to evolve wings and hence flight – and maybe, in turn, airborne prey led to the evolution of webs. From the ocean floor to the treetops, the way that arachnids have adapted to the changing times is truly enviable. The study was published in Current Biology. Related News Secret Bone Armor Discovered Beneath Skins of Australian Lizards Many Butterflies Have a Second 'Head' – This Could Be Why Your Dog May Prefer Certain TV Shows, Research Suggests Solve the daily Crossword
BBC News
5 days ago
- Science
- BBC News
Mollisonia symmetrica: Fossil suggests spiders originated in the sea
Did spiders first appear on land or in the sea? That's a question that has puzzled scientists for many years.A team of researchers in America think they might have found the discovered a tiny 500-million-year-old marine fossil that suggests that arachnids (a group of animals which includes spiders, scorpions and ticks) evolved in the ocean, before moving out of the water and adapting to land. What did scientists discover? An international team of experts led by the University of Arizona in the US, decided to take a closer look at a half-a-billion-year-old marine fossil of an extinct animal called Mollisonia undertook a detailed analysis of its well-preserved features including its brain and central nervous system. Until now, the creature was thought to be an ancient member of a specific group of arthropods known as chelicerates, which lived during the Cambrian period (around 500 million years ago) and are ancestors to modern-day horseshoe crabs. However, to the team's surprise, they found that the brain structure of the Mollisonia symmetrica was not similar to that of horseshoe crabs, as would be it had more in common with modern spiders and their led scientists to suggest that the first spiders were marine, originating in the ocean. Professor Nicholas Strausfield, the lead author of the study, said that many questions still remain over how arachnids evolved and moved from the sea to the land."It is still vigorously debated where and when arachnids first appeared and whether these were marine or semi-aquatic like horseshoe crabs."He also suggested what these ancient spiders could have fed on when they first moved on to the land. "We might imagine that a Mollisonia-like arachnid also became adapted to terrestrial life making early insects and millipedes their daily diet," Professor Strausfield team now think that Mollisonia symmetrica could be the ancient ancestor of a wide range of arachnids including spiders and scorpions.
Yahoo
6 days ago
- Science
- Yahoo
Spiders may have evolved in the ocean before adapting to land, fossil reveals
One of the creepiest, crawliest creatures of the Earth may have been swimming before adapting to live on land, new research suggests. Spiders and their arachnid relatives may have actually originated in the sea, according to analysis of an "exquisitely preserved" fossil that lived 500 million years ago. The findings were published Tuesday in the journal Current Biology. MORE: 99-million-year-old 'zombie' fungi found preserved in amber, scientists say Researchers at the University of Arizona completed a detailed analysis of the brain and central nervous system of an extinct animal called Mollisonia symmetrica, according to the study. The species was previously thought to represent an ancestral member of a specific group of arthropods called chelicerates that lived during the Cambrian period -- between 540 and 485 million years ago. Chelicerates were believed to be ancestors to modern-day horseshoe crabs. However, the scientists were surprised to discover that the neural arrangements in Mollisonia's fossilized brain are not organized like those in horseshoe crabs. Instead, they are organized the same way as in modern spiders and their relatives, the researchers said. The anterior part of Mollisonia's body -- the prosoma -- contains a radiating pattern of segmental ganglia that control the movements of five pairs of segmental appendages, the researchers said. In addition, an unsegmented brain extends short nerves to a pair of pincer-like "claws," similar to the fangs of spiders and other arachnids. The decisive feature that demonstrates the fossil was likely an early arachnid is the unique organization of the brain -- a reverse of the front-to-back arrangement found in present-day crustaceans, insects, centipedes and horseshoe crabs, the researchers said. MORE: Fossils from giant possum-like mammal that lived 60 million years ago found in Texas It's as if the brain has been "flipped backwards," which is what is seen in modern spiders," said Nick Strausfeld, a regents professor at the University of Arizona and lead author of the paper, in a statement. This may be a crucial evolutionary development, as studies of existing spider brains suggest that a back-to-front arrangement in the brain provides shortcuts from neuronal control centers to underlying circuits, which control the spider's movements, said Frank Hirth, a reader of evolutionary neuroscience at King's College London and co-author of the paper. The arrangement likely helps the spiders hunt stealthily and dexterity for the spinning of webs. The arachnid brain is "unlike any other brain" on Earth, Strausfeld said. "This is a major step in evolution, which appears to be exclusive to arachnids," Hirth said. MORE: Fossils found in North America reveal new species of 'very odd' sea monster: Scientists Spiders and scorpions have existed for about 400 million years with little change -- dominating the Earth as the most successful group of arthropodan predators. The finding challenges the widely held belief that diversification occurred only after a common ancestor had moved to the shore, according to the study. Previous fossil records appeared to indicate that arachnids lived and diversified exclusively 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. While the Mollisonia outwardly resembles some other early chelicerates from the time period, its body was composed of two parts: a rounded "carapace" in the front and a sturdy segmented trunk ending in a tail-like structure, the analysis found. Some researchers had previously compared its body composition to that of scorpions, but no one had previously claimed that it was anything "more exotic" than a chelicerate. The first creatures to come onto land were likely millipede-like anthropods and other ancestral, insect-like creatures -- an evolutionary branch of crustaceans, Strausfeld said. MORE: What paleontologists learned from fossils of a 3-eyed predator that lived 500 million years ago Early insects and millipedes were likely part of the Mollisonia-like arachnid's daily diet when they adapted to land, he added. The first arachnids on land may have also contributed to the evolution of insect wings, a "critical defense mechanism," Strausfeld said. The Mollisonia's lineage likely gave rise to spiders, scorpions, sun spiders, vinegarroons and whip scorpions, the researchers said.
Gizmodo
7 days ago
- Science
- Gizmodo
We Might Have Been Wrong About Where Spiders Came From
Technically speaking, every living thing on Earth can trace its origins to the sea. Some of these earliest creatures crawled onto land, evolving to become many different kinds of animals and insects—including, scientists believed for a long time, spiders and their relatives. A new study published today in Current Biology challenges the popular conception that spiders first emerged on land, instead suggesting that these arachnids and their relatives originated and evolved in the ocean. The team reached this conclusion by investigating the fossilized central nervous system of Mollisonia symmetrica, a long-extinct animal from the Cambrian era (between 540 and 485 million years ago), thought to be the ancestor of horseshoe crabs. Mollisonia's brain structure closely resembled that of modern spiders and their relatives, not their supposed crab descendants. 'The discovery of an arachnid brain in such an ancient creature as Mollisonia suggests that the major groups of arthropods alive today were already established then,' Nick Strausfeld, study lead author and neuroscientist at the University of Arizona, told Gizmodo in an email. He added that this 'casts a fresh view on the question: Where did arachnids first evolve?' Until now, scientists had assumed—based on the external features of arachnid-like fossils found in sedimentary rocks formed on land—that modern spiders and their relatives evolved on land. For the study, however, Strausfeld and his colleagues looked inside a well-preserved fossil of Mollisonia, which they did using an optical microscope and other imaging techniques to investigate its cerebral arrangements in higher detail. The team uncovered several similarities between modern spiders and Mollisonia, but the most striking feature was that of the creatures' central nervous system. Unlike insects, arachnid brains have a strange backward structure, in which the 'forebrain lies on top of circuits that control the movement of the legs,' Strausfeld explained. It's this that makes spiders and their relatives so 'incredibly versatile in their movements.' As the new research shows, 'the backward organization is enough of a 'tell' to demonstrate [that] Mollisonia's brain arrangement typifies those of living arachnids,' he said. Other common features the team found included external resemblances, such as jointed limbs or pincer-like claws. They bolstered their hypotheses by running a statistical analysis comparing 115 anatomical traits across both living and extinct arthropods (which includes arachnids), which placed Mollisonia as a 'sister' to modern arachnids, the authors reported in the study. 'This is very interesting, but we do not yet know how it relates to the vast array of arachnids other than spiders,' said Paul Selden, a paleontologist and arachnologist at the University of Kansas who wasn't involved in the new work, in an email to Gizmodo. 'Clearly, their conclusions on the phylogenetic [study of evolutionary history using visual cues] placement of Mollisonia are fascinating but merely mark the start of further investigation.' It's probably premature to declare spiders as spawns of the sea, but the good news is that Strausfeld and his colleagues already seem to be on the case. 'Most Cambrian fossils look very different from modern species, so it is really exciting when such outward appearances reveal something inside them—a fossilized brain and nervous system—that tells a different story,' Strausfeld said. 'Arachnids are a crucial feature of our biosphere, and we should pay attention to what they contribute to our well-being.'
RNZ News
08-07-2025
- Entertainment
- RNZ News
What you need to do to be considered "cool".
life and society about 1 hour ago What do David Bowie, Stevie Nicks, Keanu Reeves have in common? They are - by almost anyone's standards - "cool". A new psychology study has been making the rounds, and it tries to get to the bottom of a simple question: What does it mean to be a cool person? The authors widdled the answer down to six specific traits. Caleb Warren is a professor at the Eller College of Management at the University of Arizona, and one of the authors behind this study, he chats to Jesse.
