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      New Triassic fossil features sharp claws and a nasty beak

      news.movim.eu / ArsTechnica · Wednesday, 16 August, 2023 - 15:08 · 1 minute

    Image of a small reptile perched on the end of a branch, with a smaller lizard in its mouth.

    Enlarge / Artist's conception of the newly found species. (credit: Matheus Fernandes)

    It was relatively small in comparison to the giants that would follow it later in Earth’s history. With a hip height of approximately 0.3 meters (about a foot) and a length of perhaps a meter (roughly three feet), this ancient reptile existed long before the evolution of the pterosaurs most of us recognize.

    Its most striking features are its skull and hands, two body parts that rarely survive fossilization among similar animals this old. The skull consists of a raptorial-like beak without teeth, while its forelimbs end in long fingers with scimitar-like claws. These two surprising features are among many revelations in a paper published Wednesday in Nature.

    Venetoraptor gassenae is the name of this new species of lagerpetid, a type of pterosaur precursor that lived about 230 million years ago in Brazil. Named for the district of Vale Vêneto in the same municipality in which the fossil was found—and for the plundering it might have done with its beak and claws ("raptor" is Latin for "plunderer")—it is also named to honor Valserina Maria Bulegon Gassen. Although not a paleontologist herself, the authors note that she is “one of the main people responsible for the CAPPA/UFSM ” (the Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria), a paleontological research support center).

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      Dinosaurs and the evolution of breathing through bones

      news.movim.eu / ArsTechnica · Wednesday, 26 July, 2023 - 11:00

    Image of a dinosaur looming over some small mammals, potentially about to eat them.

    Enlarge / It takes careful study and the right kind of bones to determine how something like this breathed. (credit: Tito Aureliano et. al. )

    Somewhere in Earth’s past, some branches on the tree of life adopted a body plan that made breathing and cooling down considerably more efficient than how mammalian bodies like ours do it. This development might not seem like much on the surface, until you consider that it may have ultimately enabled some of the largest dinosaurs this planet has ever known. It was so successful that it was maintained by three different groups of extinct species and continues to exist today in the living descendants of dinosaurs.

    Because lungs don’t usually survive fossilization, one might wonder how scientists are able to ascertain anything about the breathing capabilities of extinct species. The answer lies within their bones.

    In a suite of papers published in late 2022 and early 2023 , paleontologists examined fossil microstructure within some of the earliest known dinosaurs to determine just how early parts of this system evolved.

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      Smelling in stereo—a surprising find on a fossilized shark

      news.movim.eu / ArsTechnica · Thursday, 6 July, 2023 - 20:58 · 1 minute

    Image of an odd looking shark swallowing a smaller fish.

    Enlarge / Artist's reconstruction of the shark as it once lived. (credit: Klug et. al. )

    Sharks are largely cartilaginous, a body structure that often doesn’t survive fossilization. But in a paper published in the Swiss Journal of Paleontology, scientists describe an entirely new species of primitive shark from the Late Devonian period, a time when they were just beginning to proliferate in ancient oceans.

    The team found several exceptionally well-preserved fossils that include soft tissues such as scales, musculature, digestive tract, liver, and blood vessel imprints. Also preserved: the species’ most distinct feature, widely separated nasal organs, somewhat akin to those on today’s hammerhead sharks. The find suggests that sharks’ finely tuned sense of smell, the subject of urban legends, was already being selected for just as these predators were becoming established.

    A key time and a rare find

    Christian Klug is the lead author and curator of the Paleontological Institute and Museum at Zurich University. He explained the significance of the Devonian period in the oceans’ history, when life was flourishing and an evolutionary arms race was in full swing. “With increasing competition among predators inhabiting the water column, the entire organism was selected for more efficiency,” he explained. “This affected swimming abilities, feeding apparatus, but also the sensory systems, which are essential to detect prey, to orient themselves in space, and to escape from even larger predators such as the huge placoderm Dunkleosteus and the equally large shark Ctenacanthus .”

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      The Paja Formation: An ecosystem of monsters

      news.movim.eu / ArsTechnica · Thursday, 23 March, 2023 - 17:22

    Image of dark brown bones on a tan background.

    Enlarge / A sea turtle of the sort found in the Paja Formation. (credit: Wikimedia Commons )

    Roughly 130 million years ago, in an area within what is now central Colombia, the ocean was filled with a diversity of species unseen today. Within that water swam several massive apex predators that are the stuff of nightmares. These marine reptiles could reach lengths of 2 to 10 meters (about 6 to 32 feet), some with enormous mouths filled with teeth, others with relatively small heads (also filled with teeth) attached to long, snake-like necks.

    These giants shared the ocean with countless smaller species, many of them predators themselves. These included ichthyosaurs—dolphin-like reptiles—as well as turtles, fish, ammonites, crabs, mollusks, sharks, and at least one species of crocodyliform .

    Allowing all these creatures to thrive must have required a flourishing ecosystem at all levels. Thanks to discoveries in what’s called the Paja Formation, a treasure trove where fossils are abundantly and exquisitely preserved, researchers are now beginning to figure out how the ecosystem supported so many apex predators. And they may find hints of how it flourished so soon after a mass extinction brought the Jurassic to a close.

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      Did Oregon once host a nesting colony of pterosaurs?

      news.movim.eu / ArsTechnica · Tuesday, 14 March, 2023 - 18:20

    The Oregon pterosaur <em>Bennettazhia oregonensis</em>, with 4 meter wingspan, reconstructed independently in seagull colors by Midiaou Diallo and reproduced with permission.

    Enlarge / The Oregon pterosaur Bennettazhia oregonensis , with 4 meter wingspan, reconstructed independently in seagull colors by Midiaou Diallo and reproduced with permission. (credit: Midiaou Diallo)

    A single fossil toe is all we have of the ‘ Mitchell ornithopod ,’ the nickname of the first early Cretaceous dinosaur fossil found in Oregon in 2018. Ornithopods were enormous herbivores such as duck-billed dinosaurs and iguanodons, and Gregory J. Retallack, lead author of that discovery, wanted to find more of its skeleton. Three years later, he returned to the site, aided by over 80 volunteers who helped excavate in more detail.

    No further ornithopod bones—indeed, no substantial dinosaur bones of any kind—were retrieved after two weeks of digging. It was, he said, “a failure” in that regard. What they found instead was a complete mess, a jumble of the remains of land-based and aquatic animals. And lots and lots of guano.

    That came from extinct flying reptiles, known collectively as pterosaurs, and suggests these animals may have flocked together on the cliffs above the coast of Oregon.

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      Sauropods had soft foot pads to help support their massive weight

      news.movim.eu / ArsTechnica · Thursday, 11 August, 2022 - 20:48 · 1 minute

    A 3D paleoreconstruction of a sauropod dinosaur has revealed that the hind feet had a soft tissue pad beneath the "heel," cushioning the foot to absorb the animals immense weight.

    Enlarge / A 3D paleoreconstruction of a sauropod dinosaur has revealed that the hind feet had a soft tissue pad beneath the "heel," cushioning the foot to absorb the animals immense weight. (credit: Andreas Jannel)

    Ask people to think of a dinosaur, and they'll likely name Tyrannosaurus Rex , the carnivorous antagonist prominently featured in the Jurassic Park and Jurassic World film franchises. But an equally well-known dinosaur clade are the herbivorous sauropods , which include Brachiosaurus, Diplodocus, Apatosaurus , Argentinosaurus , and Brontosaurus . Australian paleontologists have digitally reconstructed these plant-munching giants to glean insight into how their feet managed to support their enormous weight, according to a new paper published in the journal Science Advances.

    "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 co-author Andreas Jannel , who worked on the project while completing doctoral studies at the University of Queensland. "It is mind-blowing to imagine that these giant creatures could have been able to support their own weight on land."

    Sauropods (clade name: Sauropoda, or "lizard feet") had long-necked, long-tailed bodies that made them the lengthiest animals to have roamed the Earth. They had thick and powerful hind legs, club-like feet with five toes, and more slender forearms. It's rare to find complete Sauropod fossils, and even those that are mostly complete still lack the heads, tail tips, and limbs. Scientists have nonetheless managed to learn a great deal about them, and digital reconstruction is proving to be a valuable new tool in advancing our knowledge even further.

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      These researchers watched dead fish rot for 70 days—for science

      news.movim.eu / ArsTechnica · Tuesday, 9 August, 2022 - 22:44 · 1 minute

    These researchers watched dead fish rot for 70 days—for science

    Enlarge (credit: Aurich Lawson/T. Clements et al.)

    Sometimes science can be a messy endeavor—not to mention "disgusting and smelly." That's how British researchers described their experiments monitoring dead sea bass carcasses as they rotted over the course of 70 days. In the process, they gained some fascinating insights into how (and why) the soft tissues of internal organs can be selectively preserved in the fossil record, according to a new paper published in the journal Palaeontology.

    Most fossils are bone, shells, teeth, and other forms of "hard" tissue, but occasionally rare fossils are discovered that preserve soft tissues like skin, muscles, organs, or even the occasional eyeball. This can tell scientists much about aspects of the biology, ecology, and evolution of such ancient organisms that skeletons alone can't convey. For instance, earlier this year, researchers created a highly detailed 3D model of a 365-million-year-old ammonite fossil from the Jurassic period by combining advanced imaging techniques, revealing internal muscles that had never been previously observed.

    "One of the best ways that soft tissue can turn into rock is when they are replaced by a mineral called calcium phosphate (sometimes called apatite)," said co-author Thomas Clements of the University of Birmingham. "Scientists have been studying calcium phosphate for decades trying to understand how this process happens—but one question we just don’t understand is why some internal organs seem more likely to be preserved than others."

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      Rare 50 million-year-old fossilized bug flashes its penis for posterity

      Jennifer Ouellette · news.movim.eu / ArsTechnica · Thursday, 4 February, 2021 - 12:59 · 1 minute

    This poor fossilized assassin bug

    Enlarge / This poor fossilized assassin bug's tiny penis is being closely scrutinized by paleontologists who consider the find "a rare treat"—because it has been so extraordinarily preserved. (credit: Daniel R. Swanson/Sam W. Heads)

    A rare fossilized assassin bug is causing a bit of a stir in entomology circles, because it is so remarkably well-preserved that one can distinctly pick out its penis. The specimen dates back 50 million years to the Eocene epoch , meaning this particular taxonomic group may be twice as old as scientists previously assumed. The University of Illinois, Urbana-Champaign (UIUC) researchers who conducted the analysis described their unusual find in a new paper published in the Journal of Paleontology.

    "Getting a complete fossilized insect is really rare, but getting a fossil of an insect from this long ago, that has this much detail, is pretty amazing and exciting," Gwen Pearson of UIUC's Department of Entomology, who is not a co-author on the paper, told Ars. Assassin bugs (part of the Reduviidae family, of the order Hemiptera ) are predators favored by gardeners because they eat pests. The mouth is distinctly shaped like a straw, the better to poke into the body of its prey, like a juice box, and slurp out the guts.

    But of course, it's the preserved genitalia that make this fossilized specimen so exciting. The genitalia are contained within a shell—Ruth Schuster, writing at Haaretz , described the penis (technically its "pygophore") of the assassin bug as a "chitinous codpiece"—which is why it's difficult to tell whether a given insect specimen is male or female. In addition to the pygophore and the telltale stripes on the legs, the new fossil also distinctly shows the "basal plate," a structure shaped like a stirrup that supports the penis.

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      Is this a fossilized lair of the dreaded bobbit worm?

      WIRED · news.movim.eu / ArsTechnica · Sunday, 24 January, 2021 - 12:15 · 1 minute

    The head of a gruesome yet colorful worm projects from the seafloor.

    Enlarge (credit: Getty Images )

    Not to toot my own horn, but I know a thing or two about bizarre animals. And I can tell you without a hint of doubt that the bobbit worm is by far the most bizarre. Growing to 10 feet long , the worm digs a burrow in the seafloor, leaving only its bear trap of a mouth sticking out. When a fish approaches, the bobbit worm shoots out of its burrow with astonishing speed, snapping its jaws around its prey. With violent tugs, the worm then drags the victim down into its lair, where it eats the fish alive. (Oh, there's video .)

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    Now scientists say they've found evidence that an ancestor of the bobbit worm may have been menacing fish 20 million years ago. Writing today in the journal Scientific Reports, the researchers argue that hundreds of fossilized worm burrows, found in what is now Taiwan, show telltale signs of struggle. They haven't found the worms themselves, mind you, as boneless critters like worms (known as invertebrates, because they lack spinal columns) very rarely fossilize. Instead, they discovered trace fossils, geological features that hint at the behavior of ancient animals, in sandstone that was once a seafloor.

    "This is, we believe, the first time that we've actually found a trace fossil that shows how invertebrates like worms were feeding on vertebrates," says National Taiwan University sedimentologist Ludvig Löwemark, co-author of the new paper. "Because, typically, what we find in the sedimentary record is animals that are moving through the sediment." Invertebrates, for instance, might dig tunnels through the sea bottom and pump water through their burrows, filtering out particles. "But this is a record of a much more active behavior," he continues. "The worms were actually hiding in the sediment, jumping out, catching their prey, and then dragging this prey down into the sediment."

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