lead author – Phrynosoma http://phrynosoma.org/ Sun, 13 Mar 2022 16:03:48 +0000 en-US hourly 1 https://wordpress.org/?v=5.9.3 https://phrynosoma.org/wp-content/uploads/2021/11/profile-150x150.png lead author – Phrynosoma http://phrynosoma.org/ 32 32 New research indicates that Tyrannosaurus is actually three species – rex, imperator and regina https://phrynosoma.org/new-research-indicates-that-tyrannosaurus-is-actually-three-species-rex-imperator-and-regina/ Sun, 06 Mar 2022 11:30:33 +0000 https://phrynosoma.org/new-research-indicates-that-tyrannosaurus-is-actually-three-species-rex-imperator-and-regina/ NNA | Update: 06 March 2022 16:54 STI Washington [US]March 6 (ANI): According to a new analysis of Tyrannosaurus skeletal remains, physical differences have been revealed in the femur, other bones and dental structures between specimens that may suggest that Tyrannosaurus rex specimens should be reclassified into three distinct groups or species.The study was published […]]]>



NNA |
Update:
06 March 2022 16:54 STI

Washington [US]March 6 (ANI): According to a new analysis of Tyrannosaurus skeletal remains, physical differences have been revealed in the femur, other bones and dental structures between specimens that may suggest that Tyrannosaurus rex specimens should be reclassified into three distinct groups or species.
The study was published in the journal “Evolutionary Biology”.
Previous research has recognized the variation between Tyrannosaurus skeletal remains in the femur (thigh bone) and specimens with one or two thin incisors on either side of the anterior ends of the jaw.
Gregory Paul and his colleagues analyzed the bones and dental remains of 37 Tyrannosaurus specimens. The authors compared the sturdiness of the femur in 24 of the specimens, a measure calculated from length and girth that gives an indication of bone strength. They also measured the diameter of the base of the teeth or the space in the gums to determine if the specimens had one or two thin incisiform teeth.
The authors observed that the femur varied between specimens, some with more robust femurs and others with more slender femurs. The authors found that there were twice as many stout femora as slender femora among the specimens, suggesting that this is not a sex-caused difference, which would likely result in more splitting. equal. The authors also suggested that the variation in femora is unrelated to specimen growth, as stout femora have been found in some juvenile specimens at two-thirds the size of an adult and slender femora have been found in some specimens of adult size.
Tooth structure also varied between specimens, although those with both femur measurements and tooth remains were low (12 specimens). Specimens with an incisor tooth were correlated with an often higher femoral gracilis.

Of the Tyrannosaurus specimens, 28 could be identified in distinct layers of sediment (stratigraphy) in the Late Mastrichtian Late Formations in North America (estimated between 67.5 and 66 million years old). The authors compared Tyrannosaurus specimens with other theropod species found in lower sediment layers.
Only robust Tyrannosaurus femurs were found in the lower sediment layer (six femurs). The variation in femur robustness in the lower layer was no different from that of other theropod species, indicating that only one species of Tyrannosaurus probably existed at this point. A single Tyrannosaurus gracile femur has been identified in the middle layer with five other gracile femurs in the top layer, alongside other robust femurs. The variation in the sturdiness of the Tyrannosaurus femur in the upper sediment layer was higher than observed in some earlier theropod specimens. This suggests that Tyrannosaurus specimens found in the upper layers of sediment physically developed into more distinct forms compared to specimens from the lower layers and other dinosaur species.
Gregory Paul, lead author, said: “We found that changes in Tyrannosaurus femurs are unlikely to be related to sex or age of the specimen. We propose that changes in the femur may have evolved over time. time from a common ancestor that was more robust the femurs become more gracile in later species Differences in the robustness of femurs across sediment layers can be considered distinct enough that specimens can potentially be considered as separate species.
The authors named two potential new species of Tyrannosaurus based on their analysis. The first, Tyrannosaurus imperator (tyrant lizard emperor), concerns specimens found in the lower and middle layers of sediments, characterized by more robust femurs and usually two incisors. The authors argue that these features were carried over from earlier ancestors (tyrannosaurids).
The second, Tyrannosaurus regina (tyrant lizard queen), is related to upper and possibly middle sediment specimens, characterized by thinner femurs and an incisor tooth. The recognized species Tyrannosaurus rex (tyrant lizard king) has been identified in the upper and possibly middle layer of sediments with specimens classified as retaining sturdier femurs while having only one incisor tooth. Some specimens could not be identified based on their remains and therefore were not assigned to a species.
The authors acknowledged that they cannot rule out that the observed variation is due to extreme individual differences, or atypical sexual dimorphism, rather than separate groups, and they also cautioned that the location in the strata sediment is not known for some specimens. The authors discussed the difficulties of assigning fossil vertebrates to a potential new species.
The authors concluded that the physical variation found in Tyrannosaurus specimens combined with their stratigraphy points to three potential groups that could be designated as two new species, T. imperator and T. regina, alongside the only recognized species to date, T. rex. (ANI)

]]>
Is Tyrannosaurus more than one species of dinosaur? https://phrynosoma.org/is-tyrannosaurus-more-than-one-species-of-dinosaur/ Wed, 02 Mar 2022 01:45:12 +0000 https://phrynosoma.org/is-tyrannosaurus-more-than-one-species-of-dinosaur/ The world’s most infamous apex predator. Daniel Terdiman/CNET Tyrannosaurus was first identified over a century ago, and paleontologists have long considered the dinosaur to be a single species: the mighty T. rex that terrified children everywhere when Jurassic Park hit the big screen. in 1993. However, a new study claims that what we call Tyrannosaurus […]]]>

The world’s most infamous apex predator.

Daniel Terdiman/CNET

Tyrannosaurus was first identified over a century ago, and paleontologists have long considered the dinosaur to be a single species: the mighty T. rex that terrified children everywhere when Jurassic Park hit the big screen. in 1993. However, a new study claims that what we call Tyrannosaurus could be three separate species of dinosaurs.

The research paper, published Tuesday in Evolutionary Biology, examines the variations found in about three dozen different Tyrannosaurus fossils. The analysis conducted by the trio of researchers “favors several species” of Tyrannosaurus rather than just one. They dubbed the two new species T. imperator, or “tyrant lizard emperor,” and T. regina, or “tyrant lizard queen.”

However, other paleontologists disagree with the researchers’ conclusions.

“Ultimately, to me, this variation is very minor and does not indicate meaningful biological separation of distinct species that can be defined on the basis of clear, explicit, and consistent differences,” said Steve Brusatte, a paleontologist at the University of Edinburgh, quoted by Reuters.

While the article, and the new species of Tyrannosaurus it presents, have not been well received by the scientific community, the controversy highlights the fact that the identification of new species is often less clear cut than it is. doesn’t seem like it.

“It is concerning that this is controversial due to the charismatic status of T. rex, but on the other hand, the study would not receive as much attention otherwise,” noted independent paleontologist Gregory Paul, lead author of the paper.

Museum curators who oversee Tyrannosaurus specimens have also said they won’t rename specimens based on new research.

]]>
Scientists publish first record of false widow spider feeding on protected bat species https://phrynosoma.org/scientists-publish-first-record-of-false-widow-spider-feeding-on-protected-bat-species/ Tue, 01 Mar 2022 15:21:38 +0000 https://phrynosoma.org/scientists-publish-first-record-of-false-widow-spider-feeding-on-protected-bat-species/ Scientists in Galway have released the first record of a noble false widow spider feeding on a protected species of bat in the UK. The new study, titled Webslinger Versus Dark Knight, published in the international journal Ecosphere, shows that false widow spiders continue to impact native species. This is the first time a member […]]]>

Scientists in Galway have released the first record of a noble false widow spider feeding on a protected species of bat in the UK. The new study, titled Webslinger Versus Dark Knight, published in the international journal Ecosphere, shows that false widow spiders continue to impact native species.

This is the first time a member of the spider family Theridiidae has been recorded hunting a bat anywhere in the world, or any vertebrate in the UK. The event also marks the first time a species of false widow spider has been recorded feeding on mammals.

The study of the noble false widowhood feeding on Pipistrelle bats has been published by scientists at the National University of Ireland in Galway. The discovery was made by wildlife artist Ben Waddams at his home in North Shropshire.

For two consecutive days, bats living in the attic were found entangled in the spider web under the entrance to the roost. The first bat, a young pup, was completely immobilized with its limbs pinned tightly to the torso with silk. It was slightly shriveled and discolored from the spider feeding on the remains.

A second, much larger adult bat was also captured and entangled in the web, but as it was still alive the bat was rescued and released.

In the UK, Pipistrelle bats are protected under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017.

The gruesome occurrence isn’t as rare as people might expect – three years ago the noble false widow spider was reported feeding on a protected species of lizard native to Ireland.

Native to Madeira and the Canary Islands, the noble false widow Steatoda nobilis has the potential to become one of the most invasive spider species in the world.

It was first recorded in southern England in 1879 and has increased its range and population density in recent decades, spreading north towards Scotland and east. west through Wales and Ireland. During this period, the species also spread worldwide from Europe, East Asia, North America and South America.

The species is known for its medical importance, having the ability to cause a range of mild to severe symptoms in those bitten, but little is known about its impact on native species.

Over the past five years, the team led by Dr Michel Dugon at the Ryan Institute at NUI Galway, has studied a wide range of species-specific characteristics, including its venom, symptoms after envenomation, ecology and behavior .

Dr Dugon, head of the Venom Systems Laboratory at the Ryan Institute, said: “We’ve been working on the noble false widow for five years and have learned a lot about this species – yet we’re still amazed at its ability to s “adapt to new environments and make the most of available resources. This is a truly remarkable species.”

Dr John Dunbar, Irish Research Council postdoctoral researcher at the Venom Systems Laboratory and lead author of the study, said: “In more exotic parts of the world, scientists are documenting such spider predation events on small vertebrates for many years, but we are only beginning to realize how frequently these events occur.

“Now that this exotic species is well established in Ireland and the UK, we are witnessing such fascinating events on our doorstep.

“Even other, much smaller, false widow species have been known to capture and feed on snakes and lizards. This study presents yet another example of the invasive impact of the noble false widow on native species. know that they are much more competitive than native spiders, and this further confirms their impact on prey species.”

He added: “Although the spider has been present in Ireland for over 20 years, we do not know what its impact on the environment and ecosystem is in terms of competition with native spiders or impact on the native prey species This is important as we are beginning to have a better idea and understanding of what prey he can handle.

“In this case, bats being vertebrates, the spider’s venom has a powerful neurotoxin and this allows it to take down vertebrate prey. This makes them much more competitive than native spiders. Some studies show that the Noble False Widow’s venom is significantly more potent than native spiders.”

He said the spider would not consume the entire bat, but would feed on it until the spider was full. Spiders possess a fast-acting neurotoxic venom with a composition very similar to true black widow spiders that can cause neuromuscular paralysis in terrestrial vertebrates, allowing them to occasionally feed on small reptiles and mammals.

Aiste Vitkauskaite, a researcher at the lab, said: “The false widow spiders, much like their close relatives the black widow spiders, have extraordinary prey-catching techniques and a remarkably potent venom that allows them to capture small vertebrate prey multiple times. larger than the spider itself with surprising ease.”

For more stories of where you live, visit In your region.

]]>
Tyrannosaurus rex could actually be three species https://phrynosoma.org/tyrannosaurus-rex-could-actually-be-three-species/ Tue, 01 Mar 2022 08:00:00 +0000 https://phrynosoma.org/tyrannosaurus-rex-could-actually-be-three-species/ Everyone loves a new dinosaur. We unearth previously unidentified specimens on a semi-regular basis, and the excitement that greets each discovery speaks to the wonder we find in these ancient animals. What if new species were hiding under our noses? Take a close look at the collections of Tyrannosaurus fossils, researchers from the College of […]]]>

Everyone loves a new dinosaur. We unearth previously unidentified specimens on a semi-regular basis, and the excitement that greets each discovery speaks to the wonder we find in these ancient animals.

What if new species were hiding under our noses?

Take a close look at the collections of Tyrannosaurus fossils, researchers from the College of Charleston, USA believe we have unwittingly lumped together three closely related species of this most famous dinosaur into one basket, and it’s time to recognize not just the tyrant lizard king, but the queen and emperor too.

Editing their analysis in evolutionary biologyresearchers point to physical differences in the femoral and dental structures of 37 Tyrannosaurus specimens, saying that the observed variation in morphologies does not match the patterns expected by simple sex differences.

The authors used measurements of the length and girth of the femur bones to calculate their sturdiness, finding a distinct separation between specimens with sturdier or more slender bones. The two types of femurs were not evenly distributed in the specimen collection, suggesting that they were not associated with sex. They also did not correlate with overall size – juveniles had the same femur thickness discrepancies as adults.

Tyrannosaurus the teeth also contained clues – some had two thin incisors on either side of the front end of the jaw, while others had only one. Although only 12 of the specimens studied have both a femur and teeth, this limited data set nevertheless suggests that a single incisor tooth correlates with more gracile bones.

As a final corroboration, the authors fit their findings to a geological timeline. Of the 37 specimens studied, 29 were unearthed in the The Upper Maastrichtian formations in North America, in sediments dating from between 67.5 and 66 million years ago. The distinctly banded sediment layers at this fossil site allowed researchers to organize their specimens chronologically, with those found in the lowest layers representing the oldest in the collection.

Importantly, the most slender femurs were entirely absent from the lower layers. Instead, femurs from this layer showed only the normal degree of variation expected in any population. Researchers believe that at the time these lower layers of sediment were deposited, a single Tyrannosaurus species roamed the Earth.

The first gracilis femur appears in the middle layer, followed by five in the upper layer – a marked increase in prevalence over time. In these most recent layers, the level of variation in these bones is no longer within the bounds of normal population differences, instead painting a picture of the emergence of distinct body shapes, or “morphotypes”.

“We propose that changes in the femur may have evolved over time from a common ancestor that exhibited more robust femora to become more slender in later species,” says lead author and paleoartist Gregory Paul. “The differences in femur robustness between sediment layers can be considered distinct enough that the specimens could potentially be considered distinct species.”

Why three new species, and not two?

The authors believe that the oldest of their specimens, equipped with robust femurs and two incisors, represents a species. But even though stout femurs were also found in the more recent sediment layers, they were more likely to be accompanied by a single tooth in these more recent specimens, indicating a likely second species. Add the tapering forearm specimens, and suddenly we have a collection of three where before there was only one.

So which retains the title of tyrannosaurus rex – the tyrant lizard king?

Researchers were able to clearly recognize the king of lizards in the bones of more recent specimens, matching them to the established phenotype of this well-documented dinosaur – so these specimens will retain the famous nickname.

The researchers suggest that T. rex’s gracile cousin, found in the same layers of sediment, should be nicknamed “tyrannosaurus regina– the tyrant lizard queen.

The oldest specimens, with their sturdy forearms and double incisors, likely retained features of an earlier tyrannosaurid ancestor. The team proposes to confer on him the title of emperor, “Imperator Tyrannosaurus”.

But this expansion of Tyrannosaurus the royal family may not be without contests. While confident in their proposed new species, the authors acknowledge that assigning fossil vertebrates to new species is fraught with pitfalls. The variation observed could however turn out to be an example of extreme individual differences, or of atypical sexual dimorphism.

]]>
International trade bans on endangered species tend to help mammals but hurt reptiles | Emory University https://phrynosoma.org/international-trade-bans-on-endangered-species-tend-to-help-mammals-but-hurt-reptiles-emory-university/ Wed, 19 Jan 2022 19:36:53 +0000 https://phrynosoma.org/international-trade-bans-on-endangered-species-tend-to-help-mammals-but-hurt-reptiles-emory-university/ Bans on international trade in endangered species generally help mammals improve their status but hurt reptiles, according to a major economic study conducted by Emory University. Scientists progress published research on the impact of international trade bans by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). “We see large […]]]>

Bans on international trade in endangered species generally help mammals improve their status but hurt reptiles, according to a major economic study conducted by Emory University.

Scientists progress published research on the impact of international trade bans by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

“We see large spikes in legal trade in anticipation of reptile species bans but not in anticipation of mammal species bans, which could explain the differential effect of bans,” says Hugo Mialon, professor of economics at Emory University and lead author of the study.

The work is the largest study of its kind, spanning nearly four decades and including all mammal and reptile species for which threat level assessments are available from the International Union for Conservation of Nature (IUCN ).

Co-authors include economists Tilman Klumpp, University of Alberta, Canada; and Michael Williams, of Berkeley Research Group and Competition Economics LLC in Emeryville, California.

Their findings have important implications for policy makers. Since CITES does not operate in secret, increased trade activity in anticipation of impending trade bans is generally not avoidable.

“Anticipated peaks in trade can be particularly damaging when bans are applied to critically endangered species, as market prices for the few remaining specimens tend to be high, so eleventh-hour trade can be more intense and the recovery after the ban more difficult,” says Mialon. . “This suggests that trade bans should be implemented at lower levels of danger – in other words, when a species is near threatened rather than critically endangered.”

The authors offer several possible explanations for why the eleventh hour trade spikes did not occur – or were less pronounced – for mammalian species. One possibility is logistics, as many mammalian species in their dataset were many times larger and heavier than most reptilian species, requiring more effort to ship across international borders. Additionally, many species of reptiles, such as turtles and tortoises, are easier to catch than mammals. Finally, reptile species traded through the exotic pet trade are known to be less likely to survive physical relocation than mammals.

Mialon specializes in research on the frontiers between law and economics.

“From an early age, I was fascinated by wild animals and their importance to ecosystems,” he says. “The data available from IUCN on endangered species and CITES bans offered a chance to apply my expertise to potentially help save animal species from extinction. As far as I know, we are the first economists to tackle this subject.

Direct evidence of the effectiveness of trade bans imposed by CITES has not been conclusive. Several previous studies with small samples found that CITES regulations had a marginal effect, or no measurable effect, on endangerment.

Mialon and his colleagues took a more comprehensive approach to the issue. They focused on the period beginning in 1979, when data on CITES bans first became available, through 2018. Their analysis included the 41 species of mammals and 20 species of reptiles that received CITES bans during the study period and the thousands of species of mammals and reptiles that have been assessed by the IUCN during this period.

The status of a majority of species has deteriorated over the past four decades, due to various threats such as hunting, habitat loss and climate change. The statistical methods used by the researchers compared how the status of species that received CITES trade bans changed compared to those that did not receive bans.

Economic controls used in the study included data on GDP per capita, volume of international trade as a percentage of GDP, and population density, by country and year. For each species and year, the researchers averaged each of these variables over all countries in the species’ distribution, as recorded by the IUCN. They also constructed a measure of scientific interest in a species. And the analysis took into account factors that differ from species to species but do not change over time, such as the average adult size of a species.

an ocelot

The results indicate that, on average, trade bans work for mammals. A trade ban is associated with an average reduction in the likelihood of a species being considered endangered or worse, up to 17 percent, compared to species that have not been banned from trade.

Mammal species that eventually improved in status following a ban include the Guadalupe fur seal, gray wolf, northern bottlenose whale, ocelot, margay, sloth bear, the Samoan fruit bat, the Pacific fruit bat, Cuvier’s gazelle and the slender-horned gazelle.

“Cuvier’s gazelle and the slender-horned gazelle are clear examples of this,” says Mialon. “They were endangered in 2007 when they received a CITES ban and are ‘vulnerable’ and no longer ‘endangered’ today.”

However, the Dorcas gazelle, which has not received a CITES ban, was ‘Vulnerable’ in 2007 and remains ‘Vulnerable’ today, so it has seen no improvement in status.

“The three species are closely related, share a similar geographic distribution, and face overlapping threats,” says Mialon. “This provides an example of how trade bans work and may suggest that extending a trade ban to the Dorcas gazelle could also be effective.”

In the case of reptiles, the analysis found that a ban on international trade is associated with an average increase in the likelihood of a species being considered endangered or worse by up to 42.6%, compared to species whose trade has not been banned.

Only American and saltwater crocodiles have seen their status improve following a CITES ban. Bolson’s Tortoise, Simony’s Lizard, Bog Tortoise, Kleinmann’s Tortoise, Antsingy’s Leaf Chameleon, Flat-tailed Tortoise, Spider Tortoise and Fathead Tortoise have all seen their status deteriorate following the ban.

One limitation of the study is that historical data on the use of other conservation measures in addition to CITES bans was not available, so it could not be used as a proxy variable. control. Another limitation is that the analysis only focused on international bans.

“Many endangered animal species are not traded in international markets but still are in local and national markets,” says Mialon.

Mialon and his colleagues are currently working on another paper on the effects of CITES international trade bans on plant species.

The research received support from Competition Economics LLC and the Social Sciences and Humanities Research Council of Canada.

]]>
The ability of plants dispersed by animals to keep pace with climate change is reduced by 60% https://phrynosoma.org/the-ability-of-plants-dispersed-by-animals-to-keep-pace-with-climate-change-is-reduced-by-60/ Thu, 13 Jan 2022 08:00:00 +0000 https://phrynosoma.org/the-ability-of-plants-dispersed-by-animals-to-keep-pace-with-climate-change-is-reduced-by-60/ In one of the first studies of its kind, researchers assessed the impact of biodiversity loss in birds and mammals on the chances of plants adapting to human-induced global warming. More than half of plant species depend on animals to disperse their seeds. In a study featured on the cover of this week’s issue of […]]]>

In one of the first studies of its kind, researchers assessed the impact of biodiversity loss in birds and mammals on the chances of plants adapting to human-induced global warming.

More than half of plant species depend on animals to disperse their seeds. In a study featured on the cover of this week’s issue of ScienceAmerican and Danish researchers have shown that the ability of plants dispersed by animals to keep pace with climate change has been reduced by 60% due to the loss of mammals and birds that help these plants adapt to the changes environmental.

Researchers from Rice University, University of Maryland, Iowa State University and Aarhus University used machine learning and data from thousands of studies on the field to map the contributions of seed-dispersing birds and mammals around the world. To understand the severity of the declines, the researchers compared seed dispersal maps today with maps showing what dispersal would look like without human-caused extinctions or species range restrictions.

“Some plants live for hundreds of years, and their only chance to move is during the short period when they are a seed moving across the landscape,” said rice ecologist Evan Fricke, first author of the study.

As the climate changes, many plant species must move to a more suitable environment. Plants that rely on seed dispersers can face extinction if there are too few animals to move their seeds far enough to keep pace with changing conditions.

“If there are no animals available to eat their fruit or take away their nuts, plants dispersed by animals don’t travel very far,” he said.

And many plants that people rely on, both economically and ecologically, depend on seed-dispersing birds and mammals, said Fricke, who conducted the research while on a postdoctoral fellowship at the National Socio-Environmental Synthesis Center. (SESYNC) from the University of Maryland in collaboration with co-authors Alejandro Ordonez and Jens-Christian Svenning from Aarhus and Haldre Rogers from Iowa State.

Fricke said the study is the first to quantify the magnitude of the seed dispersal problem on a global scale and identify the regions most affected. The authors used data synthesized from field studies around the world to train a machine learning model for seed dispersal, then used the trained model to estimate the loss of dispersal from climate monitoring caused by the decline of animals.

He said that developing estimates of seed dispersal losses required two important technical advances.

“First, we needed a way to predict seed dispersal interactions occurring between plants and animals anywhere in the world,” Fricke said.

By modeling data on species interaction networks from more than 400 field studies, researchers found they could use data on plant and animal traits to accurately predict interactions between plants and seed dispersers.

“Second, we had to model how each plant-animal interaction actually affected seed dispersal,” he said. “For example, when an animal eats a fruit, it can destroy the seeds or scatter them a few meters or several kilometers away.”

The researchers used data from thousands of studies looking at how many seeds specific species of birds and mammals disperse, how far they disperse them, and how well those seeds germinate.

“In addition to sounding the alarm that the decline of animal species has dramatically limited the ability of plants to adapt to climate change, this study beautifully demonstrates the power of complex analyzes applied to huge publicly available data,” said said Doug Levey, of the National Science Foundation’s (NSF) Biological Sciences Branch Program Director, which partially funded the work.

The study showed that seed dispersal losses were particularly severe in temperate regions of North America, Europe, South America and Australia. If endangered species were to disappear, the tropical regions of South America, Africa and Southeast Asia would be the most affected.

“We found regions where climate-tracking seed dispersal decreased by 95%, even though they had lost only a few percent of their mammal and bird species,” Fricke said.

Fricke said the decline of seed dispersers highlights an important intersection of climate and biodiversity crises.

“The biodiversity of seed-dispersing animals is essential for the climate resilience of plants, which includes their ability to continue to store carbon and feed people,” he said.

Restoring ecosystems to improve the connectivity of natural habitats can counteract some declines in seed dispersal, Fricke said.

“Large mammals and birds are particularly important as long-distance seed dispersers and have been largely lost in natural ecosystems,” said Svenning, the study’s lead author, professor and director of the Center for Biodiversity Dynamics. in a Changing World from Aarhus University. “The research highlights the need to restore faunas to ensure effective dispersal in the face of rapid climate change.”

Fricke said: “When we lose mammals and birds from ecosystems, we don’t just lose species. Extinction and habitat loss damage complex ecological networks. This study shows that animal decline can disrupt ecological networks in a way that threatens the climate resilience of entire ecosystems that people rely on.”

NSF’s Levey said: “Through SESYNC and other NSF investments, we are enabling conservationists to predict what will happen to plants when their disperser ‘teammates’ disappear in the same way that we predict sports game outcomes. .”

The research was supported by the NSF (1639145), the Villum Foundation (16549), and the Aarhus University Research Foundation (AUFF-F-2018-7-8).

]]>
Discovery of extinct reptile reveals early origins of human teeth, study finds https://phrynosoma.org/discovery-of-extinct-reptile-reveals-early-origins-of-human-teeth-study-finds/ Tue, 21 Dec 2021 08:00:00 +0000 https://phrynosoma.org/discovery-of-extinct-reptile-reveals-early-origins-of-human-teeth-study-finds/ A new, extinct reptile species has shed light on how our earliest ancestors became top predators by changing their teeth in response to environmental instability around 300 million years ago. In conclusions published in Royal Society Open Scienceresearchers at the University of Bristol have found that this evolutionary adaptation laid the foundation for the incisor, […]]]>

A new, extinct reptile species has shed light on how our earliest ancestors became top predators by changing their teeth in response to environmental instability around 300 million years ago.

In conclusions published in Royal Society Open Scienceresearchers at the University of Bristol have found that this evolutionary adaptation laid the foundation for the incisor, canine and molar teeth that all mammals, including humans, have today.

Shashajaia is one of the most primitive members of a group called the Sphenacodontoidea, which includes the famous sailfish Dimetrodon, and mammal-like reptiles known as therapsids, which eventually evolved into mammals. It is remarkable for its age and anatomy, possessing a very unique set of teeth that sets it apart from other synapsids – that is, the animal line to which mammals belong – of the time.

Dr Suresh Singh from the School of Earth Sciences explained: “The teeth show a clear differentiation in shape between the front and back of the jaw, organized into distinct regions. It is the precursor to basis of what mammals have today: incisors and canines at the front, with molars at the back This is the oldest record of such teeth in our evolutionary tree.

The new teeth of Shashajaia demonstrates that large, differentiated, canine-like teeth were present in synapsids during the late Carboniferous – an era famous for giant insects and the global rainforests that produced much of our coal deposits.

By analytically comparing the dental variation observed in Shashajaia along with other synapsids, the study suggests that distinctive, specialized teeth likely arose in our synapsid ancestors as a predatory adaptation to help them catch prey at a time of global climate change around 300 million years ago. years has seen the once widespread Carboniferous wetlands replaced by more arid, seasonal environments. These new, more changeable conditions resulted in a shift in prey availability and diversity.

Lead author Dr Adam Huttenlocker of the University of Southern California said: “Canine-like teeth in small sphenacodonts like Shashajaia could have facilitated a quick raptor bite in riparian habitats where a mix of terrestrial and semi-aquatic prey could be found in abundance.”

The new reptile is one of the oldest synapsids. He was called “Shashajaia bermani“, which translates to Berman’s Bear Heart, to honor the 51-year career of veteran paleontologist Dr. David Berman of the Carnegie Museum of Natural History, as well as the local Navajo people of the Bears Ears National Discovery Site. Landmark, Utah.

Dr Singh said: “The study is a testament to Dr Berman who discovered the fossil site in 1989, and his decades of work on synapsids and other early tetrapods from the Bears Ears region of Utah, which helped justify Bears Ears National Monument in 2016.”

The site is located in an area known as the Valley of the Gods and is of great importance to paleontologists.

“The Monument archives the final stages of the Upper Paleozoic Ice Age, so understanding the changes in its fossil assemblages over time will illuminate how climate change can drastically alter ecosystems in deep time, as well as in the present” , added Dr. Huttenlocker.

Source of the story:

Materials provided by University of Bristol. Note: Content may be edited for style and length.

]]>
Discovery of extinct reptile reveals early origins of human teeth https://phrynosoma.org/discovery-of-extinct-reptile-reveals-early-origins-of-human-teeth/ Tue, 21 Dec 2021 08:00:00 +0000 https://phrynosoma.org/discovery-of-extinct-reptile-reveals-early-origins-of-human-teeth/ Credit: Dr Suresh Singh A recently discovered extinct species of reptile has shed light on how our earliest ancestors became top predators by changing their teeth in response to environmental instability around 300 million years ago. In conclusions published in Royal Society Open Science, researchers at the University of Bristol have found that this evolutionary […]]]>

Credit: Dr Suresh Singh

A recently discovered extinct species of reptile has shed light on how our earliest ancestors became top predators by changing their teeth in response to environmental instability around 300 million years ago.

In conclusions published in Royal Society Open Science, researchers at the University of Bristol have found that this evolutionary adaptation laid the foundation for the incisor, canine and molar teeth that all mammals, including humans, have today.

Shashajaia is one of the most primitive members of a group called the Sphenacodontoidea, which includes the famous sail-backed Dimetrodon and mammal-like reptiles known as therapsids, which eventually evolved into mammals. It is remarkable for its age and anatomy, possessing a very unique set of teeth that sets it apart from other synapsids – that is, the animal line to which mammals belong – of the time.

Dr Suresh Singh from the School of Earth Sciences explained: “Teeth show a clear differentiation in shape between the front and back of the jaw, organized into distinct regions. It is the basic precursor of what mammals have today: incisors and canines in the front, with molars in the back.This is the earliest record of such teeth in our evolutionary tree.

Shashajaia’s new dentition demonstrates that large, differentiated canine-like teeth were present in synapsids during the late Carboniferous, an era famous for giant insects and the global rainforests that produced much of our coal deposits .

Discovery of extinct reptile reveals early origins of human teeth, study finds

Shashajaia jaw. Credit: Dr Adam Huttenlocker

By analytically comparing the dental variation observed at Shashajaia with other synapsids, the study suggests that distinctive and specialized teeth likely emerged in our synapsid ancestors as a predatory adaptation to help them catch prey at a time when the global climate change about 300 million years ago once saw -The predominant Carboniferous wetlands are replaced by more arid seasonal environments. These new, more changeable conditions resulted in a shift in prey availability and diversity.

Lead author Dr Adam Huttenlocker of the University of Southern California said: “Canine-like teeth in small sphenacodonts like Shashajaia may have facilitated rapid raptor biting in riverine habitats where a mixture of Terrestrial and semi-aquatic prey could be found in abundance.

The new reptile is one of the oldest synapsids. It was named “Shashajaia bermani”, which translates to Berman’s Bear Heart, to honor the 51-year career of veteran paleontologist Dr. David Berman of the Carnegie Museum of Natural History, as well as the local Navajo people of discovery site inside Bears Ears National Monument, Utah.

Dr Singh said: “The study is a testament to Dr Berman who originally discovered the fossil site in 1989, and his decades of work on synapsids and other early tetrapods from the Bears Ears region of the United States. ‘Utah, who helped substantiate the Bears Ears National Monument in 2016.’

The site is located in an area known as the Valley of the Gods and is of great importance to paleontologists.

“The monument archives the final stages of the Upper Paleozoic Ice Age, so understanding the changes in its fossil assemblages over time will illuminate how climate change can drastically alter ecosystems in deep time, as well as in the present” , added Dr. Huttenlocker. .


How canines of carnivorous mammals evolved to be super killers


More information:
Adam K. Huttenlocker et al, A Carboniferous synapsid with caniniform teeth and a reassessment of the waist-like mandibular heterodontia in mammalian origin, Royal Society Open Science (2021). DOI: 10.1098/rsos.211237

Provided by University of Bristol


Quote: Extinct reptile discovery reveals oldest origins of human teeth (December 21, 2021) Retrieved January 28, 2022 from https://phys.org/news/2021-12-extinct-reptile-discovery-reveals- earliest.html

This document is subject to copyright. Except for fair use for purposes of private study or research, no part may be reproduced without written permission. The content is provided for information only.

]]>
New opossum species named after UWO biologist Greg Adler https://phrynosoma.org/new-opossum-species-named-after-uwo-biologist-greg-adler/ Wed, 08 Dec 2021 08:00:00 +0000 https://phrynosoma.org/new-opossum-species-named-after-uwo-biologist-greg-adler/ Some people are recognized when a grandchild bears their name or a scholarship is created in their honor. The legacy of biology professor Greg Adler at the University of Wisconsin at Oshkosh is solidified this week as a new species of possum he collected a decade ago is described in a publication by the American […]]]>

Some people are recognized when a grandchild bears their name or a scholarship is created in their honor.

The legacy of biology professor Greg Adler at the University of Wisconsin at Oshkosh is solidified this week as a new species of possum he collected a decade ago is described in a publication by the American Museum of natural History.

And here is the kicker …

Greg Adler

The new species featured in the December 8 issue of American Museum Novitates is called Marmosa Adleri, which is Latin for Adler’s mouse opossum.

Robert Voss, Curator of the Department of Mammalogy at the American Museum of Natural History, is the lead author of the article which describes Marmosa alderi as among the smallest measured of the sub-genre Micourea. The new species has a very long tail that is about 160% of its head and body length on average.

“The discovery of this new opossum species is very unusual as I collected it from what may be the most studied area of ​​rainforest in the world,” Adler said. “Many expeditions collected thousands of specimens there throughout the 20th century and never found this species. It is amazing that he has escaped discovery for so long.

The discovery is a culmination of Adler’s nearly 30-year career studying mammals, including rodents and opossums, in tropical rainforests around the world.

“In 2001, I captured a lot of mouse opossums, which were common and widespread in the wooded parts of central Panama. I captured an individual in a national park that had a slightly different color on the belly, and I wasn’t sure if it was just a color variation of a common species or a different species ” , Adler explained.

At the time, he had no idea that it was an unknown species.

Greg Adler with a thorny rat in central Panama, just a few miles from where he captured the new opossum species.

“In my fieldwork around the world, I had always hoped to discover a new species. Of the places I had worked, I thought my best chances were in Vietnam or French Guiana, and I thought the least likely would be central Panama because that area was much more thoroughly sampled, ”he said. -he declares.

Adler added that he was “both flattered and honored” to have a new species named after him.

“It’s kind of a reward for decades of hard work under harsh conditions in remote rainforests,” he said.

In the American Museum Novitates article, Voss elaborated on Adler’s impact:

“Adler’s numerous publications include important contributions to knowledge of seed dispersal, habitat use, community ecology, and the demography of small Neotropical mammals based on decades of research. trapping studies in Panama and northern South America. “

Back in class at UW Oshkosh, Adler teaches a number of courses, including ecology and evolution, a requirement for biology majors.

“I haven’t told any of my students about this discovery, but I probably will at some point as I stress the importance of being aware and observant whenever they are outside. . “

Learn more:

]]>
New armored species discovered in Chile had bizarre cocked tail https://phrynosoma.org/new-armored-species-discovered-in-chile-had-bizarre-cocked-tail/ Sun, 05 Dec 2021 14:46:54 +0000 https://phrynosoma.org/new-armored-species-discovered-in-chile-had-bizarre-cocked-tail/ A new kind of armored vehicle dinosaur discovered in Chile had a cocked tail never seen before in any other dinosaur. About 2 m in size, the small armored dinosaur called the ankylosaurus dates back to the Late Cretaceous Period, around 71.7 million to 74.9 million years ago. Its largely complete fossilized skeleton was found […]]]>
A new kind of armored vehicle dinosaur discovered in Chile had a cocked tail never seen before in any other dinosaur.

About 2 m in size, the small armored dinosaur called the ankylosaurus dates back to the Late Cretaceous Period, around 71.7 million to 74.9 million years ago.

Its largely complete fossilized skeleton was found in the province of Magallanes in Patagonia, the southernmost region of Chile.

Artist’s impression of a new species of armored dinosaur named Stegouros elengassen. (Artist’s impression: Mauricio Alvarez) (Mauricio Alvarez)

The dinosaur, named Stegouros elengassen, had developed a large tail weapon unlike those seen in other armored dinosaurs such as the twin spikes of Stegosaurus and the club-shaped tail of Ankylosaurus.

While its skull had features in common with other ankylosaurs, its tail armament was “bizarre,” according to the study, which was published in the journal Nature Wednesday.

The dinosaur’s tail had seven pairs of flattened bone deposits fused into a sling-like structure.

“The tail is extremely strange, because it is short for a dinosaur and the posterior half is enclosed in dermal bones (bones that grow in the skin) forming a unique weapon (tail),” said Sergio Soto Acuña, senior author of the study. and a doctoral student at the Universidad de Chile, by e-mail.

Chilean paleontologist Sergio Soto was the lead author of the study. (Courtesy of Sergio Soto) (Sergio Soto)

He said it looked like the tail of a rattlesnake or spiny tailed lizard. But unlike these creatures, the dinosaur had real bones under the scales.

The most similar feature is said to be the tail of a giant armadillo, but they are also extinct, he added.

Stegouros means “covered tail” in Greek and “elenggassen” comes from Aonikenk, the language of the first inhabitants of Patagonia, and refers to a mythological armored beast. The fossil was found in 2018.

The study noted that very few ankylosaurs had been found in southern Gondwana, the lower part of the former Pangea supercontinent.

“Unlike the ankylosaurs of the northern hemisphere, our new dinosaur has light armor, slender legs and a smaller size,” he said.

Fossilized plants discovered in the same area indicate that the climate was warmer when this dinosaur inhabited the place – very different from the current cold climate that prevails in Patagonia.

]]>