A 1.4-million-year-old trail of footprints reveals that a powerful human relative grew nearly as large as us and may have traveled in all-male groups. Eight individuals walked across the wet ground beside an ancient Kenyan lake. Within a short time, sediment buried their footprints and preserved a scene that would remain hidden for roughly 1.4 [...]Almost all of these tiny organisms vanished way back in the early Cretaceous period
The post Microfossils Help Crack Mystery More Than 100 Million Years in the Making appeared first on Nautilus.
Paleontologists have identified the earliest-known cephalopod equipped with a siphuncle -- a tubular extension of the mantle found in shelled cephalopods -- pushing back the fossil record of this key evolutionary feature to the Early Cambrian, roughly 520 million years ago.
The post 520-Million-Year-Old Fossil from China Fills Gap in Evolutionary History of Cephalopods appeared first on Sci.News: Breaking Science News.
The spots on a leopard, the stripes on a zebra, and the mask on a raccoon are all types of coloration in mammal fur, referred to as pelage. Scientists have struggled for a long time to understand how these colorations evolved. A team of researchers recently discovered how to reconstruct the colors of ancient mammal fur using cell structures that contain the chemical pigment melanin, known as melanosomes. They hope to use this understanding of ancient mammal pelage to determine how they lived and what their environments were like.
To decipher the color of ancient mammal fur, the researchers constructed a statistical computer model to predict their fur colors based on the shape of their melanosomes. First, they needed to understand how the shapes of melanosomes control fur color in modern mammals. To measure the length and width of the modern melanosomes, the scientists used a beam of electrons like a flashlight to map them in great detail, a technique called scanning electron microscopy.
They measured the length and width of 2,615 melanosomes from the fur of 116 different living mammal species, including a Red Panda, a German Shepard, and one or more species of most types in the mammalian classification. Then they recorded the wavelengths of light reflected off each melanosome using a microspectrophotometer. These wavelengths represented the exact color of hair from each melanosome they measured. This means they now had a quantitative measurement of the color of each hair to compare with its corresponding melanosome length and width.
When they examined their data, the researchers found that spherical melanosomes produced brighter fur colors, like reds and oranges, while elongated melanosomes produced darker fur colors, like browns and grays. The researchers plotted the microspectrophotometric measurements for each melanosome as a graph showing how much light it absorbed across each possible wavelength, creating reflectance curves. Based on these data, the researchers used computer software to create a statistical model that could predict reflectance curves, and therefore color, from melanosome shape alone.
Once the researchers created a model, they needed to find fossilized mammal melanosomes to predict their fur color. Mammal fossils are rare, and pieces of cells are only preserved in the most immaculate fossil deposits. In fact, these researchers only found 6 fossils of this caliber, from Mesozoic rocks deposited around 250 million years ago, soon after mammals evolved.
The fossils came from 2 world-renowned deposits in Northeastern China, the Yanliao and Jehol biotas. They selected 5 previously studied fossils from these locations, including 1 specimen of Megaconus mammaliaformis, 1 specimen of Vilevolodon diplomylos, 2 specimens from the group Docodonta, and 1 specimen from the group Eutheria. All of these animals were small, rodent-like mammals. The researchers also discovered a new species of tree-dwelling mammal, Arboroharamiya fuscus.
The scientists used scanning electron microscopy to measure a total of 2,159 fossilized melanosomes to refine their color predictions. The fossilized melanosomes were all slightly elongated spheres and had far fewer differences in shape than in modern mammals. The researchers used their model to predict reflectance curves based on the shapes of the fossil melanosomes to determine the ancient mammals’ colors. They found that all the extinct mammals they examined likely had dark brown fur without any color patterns.
Based on these findings, the researchers suggested that most, if not all, early mammals were nocturnal, like many dark-colored mammals today. They suggested that this nocturnal lifestyle probably helped them survive the meteorite impact that wiped out the dinosaurs 100 million years later. While dinosaurs were unable to survive in the post-impact wasteland, these smaller, dark-colored mammals were more resilient and thrived in the aftermath. As mammals filled the ecological roles left by the dinosaurs, they evolved new color patterns, some based solely on camouflage, and others on new factors, like sexual selection and visual communication.
The researchers concluded that their model can predict fossilized mammal colors and help determine how these ancient animals lived. Notably, their data suggest that mammals likely stayed small and nocturnal throughout the Mesozoic until the dinosaurs were gone. Future researchers could use similar methods to uncover exactly how mammals evolved the colors we see today. For example, studying mammals closer to the impact event could reveal if it took a long time to develop diverse fur patterns, or if they began before the dinosaurs’ demise. Ultimately, similar studies could help determine whether the extinction of dinosaurs was necessary for the rise of mammals.
The post What colors were prehistoric mammals? appeared first on Sciworthy.
The Chicxulub impact not only plunged Earth into an impact winter but also produced a dust blanket that later overheated the planet, according to new research from Purdue University and the University of Colorado, Boulder.
The post Dinosaur-Killing Asteroid Didn’t Just Strike Earth, Its Dust Cloud Cooked It appeared first on Sci.News: Breaking Science News.
The tracks suggest Paranthropus boisei grew surprisingly large and traveled in male groups.New research suggests fine dust trapped heat from falling debris, producing a deadly pulse that could have ignited forests around the world.An international team of paleontologists has identified a new species of early sauropodomorph dinosaur in Zimbabwe, adding to growing evidence that southern Africa hosted a richer diversity of dinosaurs during the Late Triassic epoch than previously recognized.
The post New Species of Triassic Dinosaur Discovered on Shores of Zimbabwe’s Lake Kariba appeared first on Sci.News: Breaking Science News.
Paleontologists have announced the discovery of a new fossil honeybee species that fills a long-standing gap in the evolutionary record of the genus Apis.
The post Japanese Fossil Bee Fills Two-Million-Year Gap in Honeybee History appeared first on Sci.News: Breaking Science News.
Paleontologists at the University of New South Wales have described a new genus and species of dasyurid marsupial from the Early Miocene of Australia, offering the first solid evidence that the family Dasyuridae -- which today includes quolls, Tasmanian devils and tiny antechinuses -- existed long before scientists had proof of it in the fossil record.
The post Early Miocene Fossil Rewrites Family Tree of Little Carnivorous Marsupials appeared first on Sci.News: Breaking Science News.
Paleontologists have unearthed a remarkably preserved fossil snake in Brazil that is reshaping ideas about how the earliest snakes lived and complicating the long-running debate over whether their ancestors burrowed underground, swam in the sea or crawled the surface.
The post Did Early Snakes Burrow, Swim or Crawl? 80‑Million‑Year‑Old Fossil Suggests: All Three appeared first on Sci.News: Breaking Science News.
A 201-million-year-old climate catastrophe turned Europe into a landscape of fern savannahs that repeatedly caught fire, according to new research published in the journal Nature Geoscience.
The post Fern-Fueled Wildfires Raged across Europe for Millennia during End-Triassic Mass Extinction appeared first on Sci.News: Breaking Science News.
Liopleurodon ferox is a short-necked marine reptile that patrolled the seas of what is now England and France some 163 million years ago.
The post Jurassic Pliosaur Liopleurodon Was Big, but Not as Big as Once Feared appeared first on Sci.News: Breaking Science News.
Paleontologists in India have unearthed a partial skeleton of a diminutive, previously unknown neosauropod dinosaur from the Middle Jurassic rocks of Gujarat’s Kachchh Basin.
The post Small Sauropod Dinosaur from Jurassic Period Discovered in India appeared first on Sci.News: Breaking Science News.
A new genus and species of cryptobranchid salamander that lived in lakes in Japan about 3.5 million years ago has been identified from three fossil vertebrae, filling a major gap in the fossil record of one of the world’s oldest amphibian lineages.
The post 3.5-Million-Year-Old Fossil from Japan Reveals Lost Lineage of Giant Salamanders appeared first on Sci.News: Breaking Science News.
Paleontologists have described a new genus and species of ancient gecko found in two pieces of amber from the 99-million-year-old (mid-Cretaceous) amber deposits in Kachin province, Myanmar.
The post Oldest Known Male Gecko Found Preserved in Kachin Amber appeared first on Sci.News: Breaking Science News.
The mass extinction event known as the Great Dying, which occurred 252 million years ago, resulted in the loss of 96% of marine species, and for many years, scientists could not fully explain why certain animals disappeared while others survived.
That longstanding mystery may be closer to a resolution, thanks to a recent study in the Proceedings of the National Academy of Sciences, which suggests that differences in physiology, metabolism, and oxygen use helped determine which marine animals survived the catastrophe.
Stanford University researchers found that physiological differences largely determined which marine animals survived the end-Permian mass extinction after warming oceans lost much of their oxygen. Animals whose bodies could not meet rising oxygen demands, including brachiopods and crinoids that had long ruled the seafloor, had a hard time surviving as ocean temperatures rose and oxygen in the water dropped.
By contrast, mollusks and fish possessed body plans better suited to supplying oxygen as temperatures climbed, allowing them to survive in greater numbers.
“With this study, we essentially wanted to solve the mystery of why, when you go to the beach, you collect the shells of clams and snails rather than those of brachiopods,” said lead author Jose Andres Marquez, a former PhD student in the lab of Stanford’s Erik Anders Sperling.
Marquez and his team developed a model based on species’ metabolic oxygen balance and tested it using direct measurements of oxygen use in living relatives of both ancient groups. This included brachiopods collected from the San Juan Islands in Washington. Their results revealed that the risk of extinction closely aligned with how much oxygen a species required and how effectively it could transport oxygen within its body.
Modern sea animals, such as bivalves, gastropods, and fish, have become more active and muscular over time. Their hunting habits demand more oxygen, even under normal conditions. Although this could seem like a disadvantage during harsh times, it actually worked in their favor. When ocean temperatures rose and oxygen levels dropped during the Permian-Triassic period, these animals already relied on features such as gills, strong blood flow, and larger muscles to get more oxygen when needed.
On the other hand, Paleozoic animals like brachiopods and crinoids were slow-moving filter feeders that thrived in low-oxygen environments when things were stable. However, as temperatures rose, they required more oxygen, and their bodies could not keep up with the demand in the now-oxygen-poor waters.
“Our findings show that, across different organism groups, extinctions happened at much higher rates for those more vulnerable to increases in water temperature and decreases in oxygen availability,” Marquez said.
The findings support decades of evidence from the fossil record. Brachiopods, which once accounted for thousands of species, now number about 400. In contrast, bivalves have diversified and now account for between 10,000 and 15,000 species.
Sperling previously co-authored a 2018 study that identified oxygen loss and warming as the main causes of the Great Dying. However, that earlier research used only physiological data from modern species, so the results were influenced by data from commercially important fish and crustaceans rather than from the ancient groups that have largely disappeared. The new study addresses this limitation by directly measuring the physiology of living representatives of ancient animal groups, including brachiopods.
“This study is really the final nail in the coffin for what caused the Permian-Triassic mass extinction,” Sperling said.
The environmental changes that led to the Great Dying began in oceans that were relatively cool and well-oxygenated, similar to present-day conditions. A massive release of volcanic carbon dioxide altered the atmosphere, driving global temperatures up by 8 to 12 degrees Celsius over several thousand years. By comparison, current climate projections estimate a rise of 1.5 to 4 degrees Celsius above preindustrial levels by 2100, but over a much shorter timescale. “The bad news is, we are on track for Permian-Triassic levels of warming in worst-case scenario projections,” Sperling said.
By comparing more groups of marine animals, the researchers hope to determine whether the physiological patterns that shaped Earth’s greatest mass extinction could help predict which species are most vulnerable as today’s oceans continue to warm. “We’re still at the point where we can change things and do something about it,” Sperling emphasized.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.
Paleontologists in China have discovered what they say is the earliest confirmed pieces of amber ever found, a fossilized resin roughly 385 million years old (Middle Devonian epoch) that predates the previous record-holder by about 65 million years.
The post 385-Million-Year-Old Amber Found in China appeared first on Sci.News: Breaking Science News.
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