Redesignating an endangered subspecies as a separate species could help it get protected.
Picture a skunk. You’re probably thinking of a stocky animal, around the size of a housecat, black with white stripes, like Pepé Le Pew. That describes North America’s most common skunk, the striped skunk, but they also have smaller, spotted cousins. Scientists still have a lot to learn about spotted skunks, starting with how many kinds of them even exist—over the years, the number of recognized species has ranged from two to fourteen, and lately, scientists have agreed there are four. But in a new paper in Molecular Phylogenetics and Evolution, researchers analyzed skunk <span aria-describedby="tt" class="glossaryLink" data-cmtooltip="
“>DNA and found that there aren’t four species of spotted skunk after all: there are seven.
“North America is one of the most-studied continents in terms of mammals, and carnivores are one of the most-studied groups,” says Adam Ferguson, one of the paper’s authors and the Negaunee collections manager of mammals at Chicago’s Field Museum. “Everyone thinks we know everything about mammalian carnivore systematics, so being able to redraw the skunk family tree is very exciting.”
Skunks, like raccoons, otters, and weasels, are part of the Carnivora order of mammals (they’re omnivores, though). They’re distantly related to dogs, and even more distantly related to cats. Spotted skunks are found throughout North America, but they haven’t made themselves at home in urban areas the way their striped cousins have. Most spotted skunks weigh less than two pounds, whereas striped skunks can tip the scales at over ten. Like their name suggests, they have spots instead of stripes (although technically they’re just broken stripes). And while all skunks produce a nasty-smelling spray to deter predators, spotted skunks have the flashiest means of deploying it: they do a hand-stand on their front legs as an extra warning before they spray. “Spotted skunks are sometimes called the acrobats of the skunk world,” says Ferguson.
Scientists have been interested in spotted skunks for a long time—the first species formally recognized by Western science was described in 1758 by Carl Linnaeus, the inventor of the biological naming system still used today. Over the years, as many as fourteen species were recognized, though in recent decades that number’s been condensed to four. However, Ferguson suspected that there might be more, due to the lack of genetic sequence data from morphologically distinct or geographically isolated populations of this wide-ranging genus. “We figured there had to be some surprises when it came to spotted skunk diversity, because the genus as a whole had never been properly analyzed using genetic data,” says Ferguson.
Even though North American carnivores are by and large well-known, skunks are often understudied, in part because catching skunks is a good way to get sprayed. On top of that, spotted skunks are lithe and good at climbing trees, and they’re usually found in remote areas. To acquire the specimens needed for the study, the researchers had to get creative.
“We made wanted posters that we distributed across Texas in case people trapped them or found them as roadkill,” says Ferguson, who began collecting specimens used in this project while working on his MSc at Angelo State University. “People recognize spotted skunks as something special, because you don’t see them every day, so they’re not the kind of roadkill that people just paint over.”
In addition to modern specimens, the scientists used skunks in museum collections. “If we’re trying to tell the full story of skunk evolution we need as many samples as we can,” says Ferguson. “For example, we didn’t have any modern tissues from Central America or the Yucatan. We were able to use museum collections to fill those holes.” All in all, the researchers amassed a collection of 203 spotted skunk specimens.
The researchers took tissue samples from the skunks and analyzed their DNA. Comparing the DNA sequences revealed that some of the skunks that had previously been considered the same species were substantially different. These genetic differences led the researchers to regroup some of the skunks and resurrect several species names that haven’t been used in centuries.
“I was able to extract DNA from century-old museum samples and it was really exciting to see who those individuals were related to. It turns out that one of those was a currently unrecognized, endemic species in the Yucatan,” says Molly McDonough, a biology professor at Chicago State University, research associate at the Field Museum, and the paper’s first author.
Among the new species described are the Yucatan spotted skunk, a squirrel-sized skunk found only in the Yucatan Peninsula, and the Plains spotted skunk. Plains spotted skunks have been in decline for the past century, and conservationists have petitioned for them to be listed as an endangered subspecies. “If a subspecies is in trouble, there’s sometimes less emphasis on protecting it because it’s not as distinct an evolutionary lineage as a species,” says Ferguson. “We’ve shown that the Plains spotted skunks are distinct at the species level, which means they’ve been evolving independently of the other skunks for a long time. Once something has a species name, it’s easier to conserve and protect.”
The revised skunk family tree could also be a tool for scientists looking to understand skunk reproductive biology. “Besides the fact that they do handstands, the coolest thing about spotted skunks is that some of them practice delayed egg implantation—they breed in the fall, but they don’t give birth until the spring. They delay implanting the egg in the uterus, it just sits in suspension for a while,” says Ferguson. “We want to know why some species have delayed implantation and others don’t, and figuring out how these different species of skunks evolved can help us do that.”
And while skunks aren’t always the most popular animals, the researchers say that understanding how they evolved and protecting them from extinction is important to our whole ecosystem.
“By analyzing the genome of spotted skunks, we’ve been able to learn that their evolution and splitting into different species was driven by climate change during the Ice Age,” says Ferguson. “The different lineages we found might help us find different conservation angles for protecting them in the future.”
Reference: “Phylogenomic systematics of the spotted skunks (Carnivora, Mephitidae, Spilogale): Additional species diversity and Pleistocene climate change as a major driver of diversification” by Molly M. McDonough, Adam W. Ferguson, Robert C. Dowler, Matthew E. Gompper and Jesús E. Maldonado, 22 July 2021, Molecular Phylogenetics and Evolution.
Bird reports rose during lockdowns | Cornell Chronicle – Cornell Chronicle
Around 80% of bird species examined in a new study were reported in greater numbers in human-altered habitats during pandemic lockdowns, according to new research based on data from the eBird program at the Cornell Lab of Ornithology.
In the paper, “Reduced Human Activity During COVID-19 Alters Avian Land Use Across North America,” published Sept. 22 in Science Advances, researchers compared online eBird observations from the United States and Canada from before and during the pandemic. They focused on areas within about 100 km of urban areas, major roads, and airports.
Vast amounts of data from a likewise vast geographic area were vital for this study. The researchers used more than 4 million eBird observations of 82 bird species from across Canada and the U.S.
“A lot of species we really care about became more abundant in human landscapes during the pandemic,” said study senior author Nicola Koper of the University of Manitoba, which led the research. “I was blown away by how many species were affected by decreased traffic and activity during lockdowns.”
Reports of bald eagles increased in cities with the strongest lockdowns. Ruby-throated hummingbirds were three times more likely to be reported within a kilometer of airports than before the pandemic. Barn swallows, a threatened species in Canada, were reported more often within a kilometer of roads than before the pandemic.
A few species decreased their use of human-altered habitat during the pandemic. Red-tailed hawk reports decreased near roads, perhaps because there was less roadkill when traffic declined. But far more species had increased counts in these human-dominated landscapes.
The authors filtered pandemic and pre-pandemic eBird reports so that the final data sets had the same characteristics, such as location, number of lists, and level of birdwatcher effort.
“We also needed to be aware of the detectability issue,” said co-author Alison Johnston, assistant director of the Center for Avian Population Studies and Ecological Data in the Lab of Ornithology. “Were species being reported in higher numbers because people could finally hear the birds without all the traffic noise, or was there a real ecological change in the numbers of birds present?”
The study tested whether better detectability might be a factor in the larger bird numbers reported. If it was, the scientists expected that to be more noticeable for smaller birds, which are harder to detect beneath traffic noise. However, effects were noticed across many species, from hawks to hummingbirds, suggesting that the increased numbers were not only caused by increased detectability in the quieter environments.
“Having so many people in North America and around the world paying attention to nature has been crucial to understanding how wildlife react to our presence,” says lead author Michael Schrimpf, a postdoctoral fellow at the University of Manitoba. “Studies such as this one rely on volunteer birdwatchers, so if you enjoy watching wildlife, there are many projects out there, like eBird and iNaturalist, that can use your help.”
The study was funded by Natural Sciences and Engineering Research Council of Canada with in-kind support provided by Environment and Climate Change Canada and the Cornell Lab of Ornithology.
SpaceX Crew Dragon cupola provides awe-inspiring view of the Earth from space – Californianewstimes.com
Give a few seconds (or a minute or two if needed) to startle and gaze at the Earth’s scenery from the recently launched SpaceX Crew Dragon above.
on Wednesday,Tied to the SpaceX Crew Dragon with one of the upgrades: Cupola. The transparent dome at the top of the Dragon Capsule provides the Inspiration 4 crew with the best views of the Earth that up-and-coming astronauts can dream of. This is the first time a cupola has been installed on a dragon. Dragons typically carry astronauts and cargo to the ISS, with docking ports at the top instead of windows.
A short video posted to the SpaceX Twitter account hours after the launch shows the cupola’s transparent dome against the Earth, which is a pale blue marble.
As the Crew Dragon orbits from a height of 585 kilometers (more than 360 miles), our planet is exposed to the sun and slowly roams around the orbs.
Inspiration 4’s crew (commander Jared Isaacman, doctor’s assistant, childhood cancer survivor Haley Arseno, aerospace engineer Chris Sembroski, African-American geology professor Sian Proctor) are in orbit for three days. Ride and stare at the cupola and the earth.
And did you say that the cupola is right next to the dragon’s toilet? Yeah, the view of the earth should be visible from the crew dragon’s bathroom. Isaacman told insiders Toilets are one of the few places where you can separate yourself from others with privacy curtains and have the best toilet windows of mankind. “When people inevitably have to use the bathroom, they will see one view of hell,” he said.
Astronauts who have been to space often talk about a phenomenon called the “overview effect.” Looking at the planet from above, the idea is that the way we think about the planet and the mass of humankind that depends on it will change. There may be a lot of revelation at the end of the Inspiration 4 journey, as I don’t know if they thought of it while sitting in the can.
The mission is the first mission to take off from the Florida coast on Wednesday night and be launched with four civilians. It is expected to return to Earth on Saturday and land in the Atlantic Ocean.
SpaceX Crew Dragon cupola provides awe-inspiring view of the Earth from space Source link SpaceX Crew Dragon cupola provides awe-inspiring view of the Earth from space
Oldest human footprints in North America found in New Mexico – Al Jazeera English
Fossilised footprints dating 23,000 years push back the known date the continent was colonised by thousands of years.
Footprints dating back 23,000 years have been discovered in the United States, suggesting humans settled North America long before the end of the last Ice Age, according to researchers.
The findings announced on Thursday push back the date at which the continent was colonised by its first inhabitants by thousands of years.
The footprints were left in mud on the banks of a long-since dried up lake, which is now part of a New Mexico desert.
Sediment filled the indentations and hardened into rock, protecting evidence of our ancient relatives, and giving scientists a detailed insight into their lives.
The first footprints were found in a dry lake bed in White Sands National Park in 2009. Scientists at the United States Geological Survey recently analysed seeds stuck in the footprints to determine their approximate age, ranging from 22,800 to 21,130 years ago.
“Many tracks appear to be those of teenagers and children; large adult footprints are less frequent,” write the authors of the study published in the American journal Science.
“One hypothesis for this is the division of labour, in which adults are involved in skilled tasks whereas ‘fetching and carrying’ are delegated to teenagers.
“Children accompany the teenagers, and collectively they leave a higher number of footprints.”
Researchers also found tracks left by mammoths, prehistoric wolves, and even giant sloths, which appear to have been approximately at the same time as the humans visited the lake.
The Americas were the last continent to be reached by humanity.
For decades, the most commonly accepted theory has been that settlers came to North America from eastern Siberia across a land bridge – the present-day Bering Strait.
From Alaska, they headed south to kinder climes.
Archaeological evidence, including spearheads used to kill mammoths, has long suggested a 13,500-year-old settlement associated with so-called Clovis culture – named after a town in New Mexico.
This was considered the continent’s first civilisation, and the forerunner of groups that became known as Native Americans.
However, the notion of Clovis culture has been challenged over the past 20 years, with new discoveries that have pushed back the age of the first settlements.
Generally, even this pushed-back estimate of the age of the first settlements had not been more than 16,000 years, after the end of the so-called “last glacial maximum” – the period when ice sheets were at their most widespread.
This episode, which lasted until about 20,000 years ago, is crucial because it is believed that with ice covering much of the northern parts of the continent, human migration from Asia into North America and beyond would have been very difficult.
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