Latest news with #UniversityofArizona
Time of India
a day ago
- Science
- Time of India
Did spiders swim before they could crawl? Fossil analysis reveals shocking information
Image credits: X/@PondManUK While many are understandably scared of snakes, what most seem to be terrified of are little, crawling creatures called spiders. Now it seems these crawlers were swimming in good ole waters before adapting to land and engaging in a never-ending game of I-spy with humans. According to the analysis of an "exquisitely preserved" fossil that existed 500 million years ago, spiders and their arachnid relatives may have actually originated in the sea. In a research published in the journal Current Biology, researchers at the University of Arizona performed a detailed examination of the brain and central nervous system of an extinct animal called Mollisonia Symmetrica. The species was previously believed to represent a specific group of arthropods called chelicerates that lived during the Cambrian period, between 540 and 485 million years ago. They were believed to be the ancestors of horseshoe crabs. However, after finding the neural arrangements in the creature's fossilized brain, the researchers understood that they were not organized like those in horseshoe crabs. Instead, they were organized akin to the ones in modern spiders and their relatives, said the researchers. 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. Additionally, an unsegmented brain in their body extends short nerves to a pair of pincer-like "claws" similar to the fangs of spiders and other arachnids. Apart from all of this, the decisive feature that classifies the fossil as an early arachnid is the organisation of its brain, which has a reverse order to the front arrangement found in present-day crustaceans, insects, centipedes and horseshoe crabs, as per the researchers. It's as if the brain has been "flipped backwards," which is what is seen in modern spiders," said Nick Strausfeld, lead author of the paper and a regents professor at the University of Arizona, in a statement. The back-to-front arrangement in the spider brain provides shortcuts from neuronal control centres to underlying circuits, which control their movement. It also helps them with the stealth for hunting and dexterity for spinning webs. Why is the study shocking? Image credits: X Well, first, it changes our entire belief that spiders have been crawling the surface of the planet forever. Spiders and scorpions have existed on the planet for about 400 million years with little change, thus being the most successful group of arthropodan predators. The study challenges the long-held belief that the arachnids lived and diversified only 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. According to the researchers, the Mollisonia's lineage gave rise to spiders, scorpions, sun spiders, vinegarroons and whip scorpions.
The Independent
5 days ago
- Science
- 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.
Yahoo
5 days ago
- Science
- Yahoo
Spiders may have originated in the ocean before adapting to live on land
New research suggests spiders and other arachnids may have originated in the sea, based on analysis of a 500-million-year-old fossil. 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. Researchers say the Mollisonia's ancestry likely led to spiders, scorpions, sun spiders, vinegaroons and whip scorpions.
The Independent
5 days ago
- Science
- The Independent
Spiders may have originated in the ocean before adapting to live on land
New research suggests spiders and other arachnids may have originated in the sea, based on analysis of a 500-million-year-old fossil. 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.
6 days ago
- Science
Spiders may have evolved in the ocean before adapting to land, well-preserved 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. 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. 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. 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. 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.
