Fissidentalium shirleyae

Scientists have long known that, just like humans, many species of mammals and birds experience REM (rapid eye movement) sleep – a type of deep sleep during which most dreaming occurs. However, until recently, not much attention has been given to the sleeping patterns of spiders.&nbsp;



Now, a research team led by the <a href="https://www.uni-konstanz.de/en">University of Konstanz</a> in Germany has recorded over 30 baby <a href="https://www.earth.com/news/jumping-spiders-know-the-difference-between-animals-and-objects/">jumping spiders</a> (Evarcha arcuata) during their resting states, and found that they displayed periodical bouts of retinal movements coupled with limb twitching and leg curling, suggesting that they might experience REM sleep too.



While many species similar to spiders do not have movable eyes, which makes it difficult to investigate their sleep cycles, jumping spiders are fierce predators that move their retinal tubes around constantly to redirect their gaze when they hunt.&nbsp;



Moreover, baby jumping spiders have a see-through outer layer which gives scientists a clear window into their bodies. “Sometimes as a biologist, you just get really, really lucky,” said study co-author Paul Shamble, an evolutionary biologist at <a href="https://www.harvard.edu/">Harvard University</a>.&nbsp;



By filming the baby spiders while they were resting, the researchers were surprised to find that they exhibited similar movements and behaviors as other species known to experience REM sleep.&nbsp;



“Here, we report evidence for an REM sleep-like state in a terrestrial invertebrate – periodic bouts of retinal movements coupled with limb twitching and stereotyped leg curling behaviors during nocturnal resting in a jumping spider,” the study authors reported.&nbsp;



“Observed retinal movement bouts were consistent, including regular durations and intervals, with both increasing over the course of the night.&nbsp;This report provides direct evidence for an REM sleep-like state in a terrestrial invertebrate – an arthropod – with clear parallels to REM sleep in terrestrial vertebrates.”



However, scientists are still not sure whether the spiders are technically asleep while they are in these resting states. Experts such as Jerry Siegel, a sleep researcher at the <a href="https://www.ucla.edu/">University of California, Los Angeles</a> (UCLA), remain skeptical that spiders are in fact capable of REM sleep. “There may be animals that have activity in quiet states. But are they REM sleep? It’s hard to imagine that they could be the same thing,” he said.



Further research is needed to better understand the sleeping patterns of spiders and other similar animals, and clarify how widespread REM sleep is in the animal kingdom, and what evolutionary purposes it might serve. “Comparisons across such long-diverged lineages likely hold important questions and answers about the visual brain, as well as the origin, evolution, and function of REM sleep,” the authors concluded.



The study is published in the journal <a href="https://doi.org/10.1073/pnas.2204754119">Proceedings of the National Academy of Sciences</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer&nbsp;&nbsp;

Jumping spiders may experience REM sleep

Scientists have long known that, just like humans, many species...

A new study led by the <a href="https://www.ucla.edu/">University of California, Los Angeles</a> (UCLA) has found that female white-faced <a href="https://www.earth.com/news/age-rated-genes-help-capuchin-monkeys-live-longer/">capuchin monkeys</a> living in the tropical forests of northwestern Costa Rico that are better integrated into social networks with other adult females tend to survive longer.



“As humans, we assume there is some benefit to social interactions, but it is really hard to measure the success of our behavioral strategies,” said study senior author Susan Perry, a field primatologist at UCLA. “Why do we invest so much in our relationships with others? Does it lead to a longer lifespan? Does it lead to more reproductive success? It requires a colossal effort to measure this in humans and other animals.”



Together with her research team, Professor Perry tracked the female capuchin monkeys’ social interactions with other females, males, and companions of any sex and age, based on 18 years of data. Interactions taken into account in the study included giving and receiving grooming, foraging nearby, and taking part in coalitionary conflicts, such as intervening to help one another in conflicts by fighting, chasing, or producing aggressive sounds and facial expressions.



While the analyses revealed no evidence that heterosexual relationships provided any survival-related benefits to females, they clearly shown that social integration into networks with other female adults significantly improved their chance of survival. 



“We found the strongest evidence that social integration into female networks predicts survival. Females who frequently engaged in grooming and foraged in close proximity with other females experienced improved survivorship,” the authors explained.



“We also found marginal support that females who frequently provided and received coalitionary support from other females possibly experienced survival-related benefits. The fact that female interactions with other females across all behavioral domains show at least some evidence of beneficial impact on survival suggests that females cultivate strong relationships with each other.”&nbsp;&nbsp;&nbsp;



Further research is needed to better understand why relationships with other females have the greatest impact on the survival of female capuchin monkeys, and to investigate whether this phenomenon can be found in other species of monkeys.



The study is published in the journal <a href="https://academic.oup.com/beheco/article/33/4/807/6598784">Behavioral Ecology</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer&nbsp;&nbsp;

Female monkeys with strong friendships survive longer

A new study led by the University of California, Los...

Sponges are ancient filter-feeding animals that rely on maintaining a flow of water through their bodies to obtain suspended food and dissolved <a href="https://www.earth.com/news/oxygen-may-have-come-from-ancient-rocks-of-early-earth/">oxygen</a>. They do not have a nervous, digestive or circulatory system, and remove waste products by releasing them into this same flow of water. However, a new study that analyzed videos of sponges over extended time periods has identified a special technique that they use to get rid of unwanted material from inside their bodies.&nbsp;



As one of the oldest multicellular organisms in existence, a sponge spends most of its life stuck to the substratum and cannot move away when conditions become unpleasant. Under these circumstances it may take in unwanted particles of sediment with its constant inflow of water. These waste particles would soon clog up a sponge’s filtration system and so they need to be removed. And the sponge does this by undergoing an extended contraction, referred to as a “sneeze.”



"Our data suggest that sneezing is an adaptation that sponges evolved to keep themselves clean,” said study senior author Jasper de Goeij, a marine biologist at the <a href="https://www.uva.nl/en">University of Amsterdam</a>.



While biologists have known about the contraction behavior, the authors of this paper show that these sneezes get rid of materials the sponges cannot use. “Let’s be clear: sponges don’t sneeze like humans do. A sponge sneeze takes about half an hour to complete. But both sponge and human sneezes exist as a waste disposal mechanism,” says de Goeij.



The researchers used time-lapse videos of sponges to show that these organisms do not simply dispose of waste and unwanted particles with water that flows away through the outlet pores. They actively secrete mucus, often against the direction of water flow, onto their outer surfaces. They then expel unwanted particles through their pores and these become aggregated in the stringy clumps of mucus. Every now and then, the sponge goes through a contraction (sneeze) that loosens the strings of mucus and accumulated particulate matter, dispatching them into the water column.



What is a sponge’s waste is a fish’s windfall. Fish hang around the sponges waiting for these strings of mucus to be shed so that they may eat them.



“We also observed fish and other animals feeding off of the sponge mucus as food,” explained study first author Niklas Kornder. “Some organic matter exists in the water surrounding the coral reef, but most of it is not concentrated enough for other animals to eat. Sponges transform this material into eatable mucus."



The researchers noted this “sneezing” behavior in two species of sponges, the Caribbean tube sponge&nbsp;Aplysina archeri&nbsp;and another Indo-Pacific species of the genus&nbsp;Chelonaplysilla.&nbsp;



“We actually think that most, if not all, sponges sneeze. I’ve seen mucus accumulate on different sponges while diving and in pictures taken by other scientists for other purposes,” said Kornder. 



“Our findings highlight opportunities to better understand material cycling in some of the most ancient Metazoans,” wrote the study authors.



There are still many aspects about sponge “sneezes” that remain to be investigated. “In the videos, you can see that the mucus moves along defined paths on the surface of the sponge before accumulating. I have some hypotheses, but more analysis is needed to find out what is happening,” said Kornder.



“There are a lot of scientists that think sponges are very simple organisms, but more often than not we are amazed by the flexibility that they show to adapt to their environment,” said de Goeij.



The study is, published in the journal <a href="http://dx.doi.org/10.1016/j.cub.2022.07.017">Current Biology</a>.



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By <a href="mailto:bosman@truewan.co.za">Alison Bosman</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Sponges “sneeze” to get rid of unwanted waste

Sponges are ancient filter-feeding animals that rely on maintaining a...

How did enormous dinosaurs like Brontosaurus carry so much weight on land? A new study led by the <a href="https://www.uq.edu.au/">University of Queensland</a> has finally solved this mystery. Using 3D modeling, the experts digitally reconstructed the foot bones of various <a href="https://www.earth.com/news/giant-sauropods-walked-more-like-hippos-than-elephants/">sauropods</a> to test their function. 



Dr. Andréas Jannel conducted the research during his PhD studies at UQ’s Dinosaur Lab. He said the team discovered that the hind feet of sauropods had a soft tissue pad beneath the "heel" that added cushioning to absorb their immense weight.



“We’ve finally confirmed a long-suspected idea and we provide, for the first time, biomechanical evidence that a soft tissue pad – particularly in their back feet – would have played a crucial role in reducing locomotor pressures and bone stresses,” said Dr. Jannel. “It is mind-blowing to imagine that these giant creatures could have been able to support their own weight on land.”



It was once assumed that sauropods were semi-aquatic and that water buoyancy took literal tons of weight off their relatively small legs. This theory was contradicted in the mid-twentieth century when scientists analyzed sauropod tracks that were found in deposits on land.



Sauropods were also once believed to have feet similar to a modern-day elephant, noted study co-author Dr. Olga Panagiotopoulou of Monash University.



“Popular culture - think Jurassic Park or Walking with Dinosaurs - often depicts these behemoths with almost-cylindrical, thick, elephant-like feet,” said Dr. Panagiotopoulou. “But when it comes to their skeletal structure, elephants are actually ‘tip-toed’ on all four feet, whereas sauropods have different foot configurations in their front and back feet."



“Sauropod’s front feet are more columnar-like, while they present more ‘wedge high heels’ at the back supported by a large soft tissue pad.”



This was because sauropods and elephants had different evolutionary origins, explained study co-author Professor Steve Salisbury.&nbsp;



“Elephants belong to an ancient order of mammals called proboscideans, which first appeared in Africa roughly 60 million years ago as small, nondescript herbivores. In contrast, sauropods – whose ancestors first appeared 230 million years ago – are more closely related to birds," said Professor Salisbury.



“They were agile, two-legged herbivores and it was only later in their evolution that they walked on all fours. Crucially, the transition to becoming the largest land animals to walk the earth seems to have involved the adaptation of a heel pad.”



The study is published in the journal <a href="https://www.science.org/journal/sciadv">Science Advances</a>.



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Mystery solved: how massive dinosaurs carried their weight

How did enormous dinosaurs like Brontosaurus carry so much weight...

Many <a href="https://www.earth.com/news/dinosaurs-self-regulated-their-body-temperature/">dinosaurs</a> replaced their teeth as they fell out - a trait that is shared with modern crocodilians and sharks. Tooth replacement is useful for predatory animals whose teeth are used to hold struggling prey animals and are often broken off.&nbsp;



Now, new research shows that spinosaurids (a group that includes spinosaurus) replaced their teeth even faster than many other dinosaurs. This helps explain why so many spinosaurid teeth have been found littering dinosaur digs.&nbsp;&nbsp;&nbsp;



A team of scientists led by the <a href="https://www.ehu.eus/en">University of the Basque Country</a> assessed a partial spinosaurid jaw from the Late Cretaceous found in La Rioja, Spain. The jaw contained eight alveoli or tooth sockets and tooth remains. Indeed, the researchers found up to three teeth in a single alveolus.&nbsp;



“We recognized up to three generations of teeth in the same alveolus: the functional tooth of the animal, another tooth being formed and which would replace the first, and the germ of the one that would end up replacing the second,” explained Pablo Navarro, co-author of the research published in the journal <a href="https://www.tandfonline.com/doi/full/10.1080/08912963.2022.2069019">Historical Biology</a>.



“This suggests very rapid tooth replacement and is probably one of the reasons why so many spinosaurid teeth can be&nbsp; found on the Iberian Peninsula during the Lower Cretaceous."



Previous research showed that some species of spinosaurids were able to quickly replace their conical teeth, with an estimated time of 60 to 68 days. This research not only verifies the trait for the entire group, but also explains the mechanism of how this regeneration is possible.&nbsp;&nbsp;&nbsp;



“Throughout their lives these animals grew new teeth that gradually replaced the original ones and caused them to fall out. This means that the same animal could generate multiple teeth,” said Navarro.



“These teeth, more or less conical in shape and a centimetre in size, were transported by rivers, accumulated in lake areas and, over time, became fossilised,” said the researcher. They are one of the most common vertebrate remains in Iberian sites of the Lower Cretaceous (between 145 and 113 million years ago)”.



Although scientists aren’t entirely sure why spinosaurid teeth were replaced so quickly, it’s likely this ability gave them an edge over other predators.&nbsp;



The study is published in the journal <a href="https://dx.doi.org/10.1080/08912963.2022.2069019">Historical Biology&nbsp;</a>



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By <a href="mailto:nire518@gmail.com">Erin Moody </a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Spinosaurids rapidly replaced their teeth

Many dinosaurs replaced their teeth as they fell out -...

A new study from <a href="https://www.ncsu.edu/">North Carolina State University</a> explores the connection between hearing loss and dementia in geriatric <a href="https://www.earth.com/news/playfulness-is-a-key-personality-trait-of-gifted-dogs/">dogs</a>. These findings could support treatment of aging dogs and advance our understanding of the relationship between sensory loss and cognitive function.



“In humans, we know that age-related hearing loss is estimated to affect one-third of people over age 65,” said study co-author Natasha Olby.&nbsp;



“We also know that the rate of cognitive decline is approximately 30-40% faster in people with age-related hearing loss and that hearing loss is a greater contributor to dementia risk than other factors such as hypertension or obesity. But we don’t understand whether the same holds true for dogs.”



The researchers evaluated 39 senior or geriatric dogs. Auditory and cognitive tests were performed and owners were asked to fill out questionnaires focused on cognitive ability and quality of life. Cognitive testing, questionnaire scores and age were compared between hearing groups.



The “average” dog can hear tones at 50 decibels (dBs) with no difficulty. Of the study cohort, 19 of the dogs could hear at 50 dBs, 12 at 70 dBs, and eight at 90 dBs (roughly equivalent to the noise made by a jet plane at takeoff).&nbsp;



When the hearing results were compared with quality of life questionnaire responses, scores related to vitality and companionship declined significantly as hearing deteriorated. The results from cognitive testing were similar - as hearing declined, so did the dog’s ability to perform tasks.



“Hearing loss is one of the biggest predictors of dementia in people,” said Olby. “Hearing loss also contributes to falls in elderly people, as sensory decline contributes to a loss in motor skills. So the connection between physical and neurological decline is clear for humans.”



These findings suggest that the same connection happens with aging dogs. Understanding these changes in elderly dogs enhances the ability to identify and treat these issues in pets, but also improves the understanding of the same issues among humans.



The study appears in the <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.16510">Journal of Veterinary Internal Medicine</a>.&nbsp;



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By <a href="mailto:katherinebucko@gmail.com">Katherine Bucko</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Hearing loss linked to dementia in aging dogs

A new study from North Carolina State University explores the...

Oak savannas are grassy and shrubby areas, featuring oaks as the dominant <a href="https://www.earth.com/news/heat-makes-pine-trees-more-susceptible-to-disease/">tree</a> species. Since oaks require a dry environment, in North America these savannas are frequently found in the rain shadow of the West Coast’s mountain range. Oaks host a vast diversity of insect species, such as oak gall wasps, which form striking growths known as galls. However, the expansion of this invasive wasp species has usually been kept in check by a wide range of parasitoid wasps, which lay their eggs inside the galls, and, after hatching, their larvae feed upon the oak gall wasp larvae.&nbsp;



According to a new study led by <a href="https://www.binghamton.edu/">Binghamton University</a> in New York, climate change has led to warming temperatures in the Pacific Northwest, leading some insect species – including the oak gall wasps - to expand their range into more northerly oak savannas, where they encounter less competition and they can proliferate. “In the native range, you might find a handful of galls on a single leaf. In the expanded range, sometimes you’re finding thousands on a single tree,” said study senior author Kirsten Prior, an assistant professor of Biological Sciences at Binghamton. “This is pretty prevalent throughout Vancouver Island.”



Biodiversity tends to work on a latitudinal gradient: while there is a vast multitude of species closer to the equator, their numbers gradually decrease at higher latitudes. Thus, when species expand their range northwards due to warming temperatures, they often move into areas without a diversity of predators and competitors, eventually overwhelming the ecosystems they encounter.



“When species undergo poleward range expansions in response to anthropogenic change, they likely encounter less diverse communities in new locations. If low diversity communities provide weak biotic interactions, such as reduced competition or predation, range-expanding species may experience high niche opportunities,” the study authors explained.



This seems to happen currently with oak gall wasps, which exhibit unusual population growths at higher latitudes, where they need to face less competition – a phenomenon highlighting the importance of biodiversity for keeping invasive species in check, as well as the potential long-term ramifications of climate change.



“Biodiversity can be really important in potentially protecting areas from invading species. If we have strong competitors and predators, this might make areas less susceptible to invading species,” concluded study lead author Dylan Jones, a doctoral student in Biology at Binghamton.



The study is published in the <a href="http://dx.doi.org/10.1111/1365-2656.13780">Journal of Animal Ecology</a>.&nbsp;



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer&nbsp;&nbsp;

Invasive wasps are expanding northward on the West Coast

Oak savannas are grassy and shrubby areas, featuring oaks as...

Fissidentalium shirleyae

Taxonomic tree: