Latest news with #MH7
Yahoo
18-02-2025
- Science
- Yahoo
Amazing Fossil Reveals Turtle-Like Scales on Jurassic Plesiosaur
Serpentine-necked, four-flippered plesiosaurs were among the most successful marine predators in the time of dinosaurs. A remarkably complete and well-preserved fossil has revealed that at least some of these mighty hunters had flipper scales similar to today's sea turtles, which may have aided in either swimming or dragging themselves along the seafloor. While plesiosaur fossils have been found worldwide, only about eight samples of their soft tissues have been recorded so far. Lund University paleontologist Miguel Marx and colleagues' new analysis uses microscopy and spectroscopy to provide never-before-known details of what these animals looked like. These fossilized bones belonged to a roughly 4.5-meter-long plesiosaur that swam Earth's oceans 183 million years ago, during the Jurassic, when plesiosaurs were especially common, the team confirmed. Designated MH 7, they were excavated from Holzmaden in Germany back in 1940, then spent some time buried in a museum garden for protection during WWII, followed by long-term storage. Plesiosaurs bore live babies and breathed air, traits that suggest they may have been warm-blooded. And while the skin from this fossil's tail was smooth like today's warm-blooded marine animals, a sample from the right fore flipper revealed small irregular triangular structures. The researchers compared the fossilized skin samples to animals still living today. "[The flippers] clearly differ from the soft, scale-less skin occurring around the tail of MH 7 and instead compare closely with carapace scutes of fossil and living turtles, as well as mosasauroid marine lizard scales," they write in their paper. As well as the scales, the thickness of their skin was also comparable to living sea turtles. These anatomical features may have evolutionarily converged towards similar shapes thanks to shared hydrodynamic pressures, the team suspects, or to help provide traction on the seafloor substrate. "Another purpose of the flipper scales in MH 7 may have been to provide a protective covering for traction on the seafloor during benthic grazing," add the researchers. "This is consistent with plesiosaur 'bottom-walking' and feeding traces as well as preserved gastric contents which comprise coarse sediment masses." Several species have been found with fossilized gut contents full of bottom-dwelling snails and crustaceans. Pigment cells were also found close to the outer surface of MH 7's tail skin, but not on the surface of the flipper, which is much tougher. "These cells are characterized by corneous beta-proteins that make living reptile scales hard and immobile," Marx and team explain. So it seems plesiosaurs retained their reptilian scales after transitioning from land into their marine form, unlike other marine reptiles at the time, such as the more fish-shaped ichthyosaurs, that instead lost their scales to reduce drag in water. The scales "along the trailing edges of the flippers undoubtedly fulfilled some functional role and presumably conferred a selective advantage for plesiosaurs during their protracted evolution as one of the most successful pelagic tetrapod clades," the researchers conclude. This research was published in Current Biology. Earthquake Swarm Mystifies Scientists as Greek Island Tremors Continue Most Birds-of-Paradise Are Secretly Biofluorescent, Study Finds Scientists Just Found The Perfect Disguise to Sneak Into a Termite Colony
Yahoo
06-02-2025
- Science
- Yahoo
Paleontologists solve decades' old mystery about plesiosaur skin texture
Scaly or smooth? That has long been one of paleontology's enduring questions about the plesiosaur. While experts know details about its diet, size, and general habitat, the aquatic reptile's skin characteristics have remained a mystery. But for the first time ever, researchers at Sweden's Lund University have analyzed a rare plesiosaur specimen's fossilized soft tissue samples, and now believe they can finally answer the decades' old question: In actuality, the 183-million-year-old dinosaur relative's skin had a bit of both. 'The classic life reconstruction of plesiosaurs (Plesiosauria), incorporating a long neck, compact body, and four propulsive flippers, has not changed for nearly 200 years. However, the actual external appearance of these famous Mesozoic reptiles is largely unknown,' explained the team in their paper published on February 6th in the journal, Current Biology. Paleontologists have previously examined fossilized soft tissues from other prehistoric marine reptiles, including ancient sea turtles and ichthyosaurs. With only around eight known fossil tissue samples to date, plesiosaurs have proven much more difficult to study. As New Scientist explained on Thursday, this is especially true given that most examples belong to museums that prohibit the use of potentially destructive imaging tools. But paleontologists finally got their chance with a fossil set known as MH7—although it took years to get to that point. MH7's 85-year-journey from excavation to laboratory analysis began in 1940, when German paleontologists first discovered its fossils inside a quarry. Due to the ongoing dangers of World War II, MH7 was subsequently reburied in a garden to protect it from accidental damage. Researchers exhumed the fossils yet again after the end of the war, but this time transported them into safekeeping at Urwelt-Museum Hauff in the nearby town of Holzmaden. In 2020, the Lund University paleontologists finally arranged to assemble and prepare the 183-million-year-old, 11.5-foot-long MH7 for its first-ever detailed tissue examination. Researchers first treated and sterilized thin sections of fossil using a mixture of ultrapure water and ethanol. They then placed the demineralized samples onto slides, and examined the selections using techniques including transmitted light microscopy, scanning electron microscopy, electron backscatter diffraction, and infrared microspectroscopy. The team originally theorized the skin might possess the dolphinlike, scaleless qualities of an ichthyosaur, but were surprised at what they found: areas of both scaly and smooth skin. More specifically, it appears that its flippers featured scaly sections, while the rest of its body and tail was scaleless. Researchers theorize the textured flippers allowed the animal to better move along the seafloor while hunting for prey, and the smoother portions reduced drag while swimming. Taken altogether, it's likely that plesiosaur skin looked like a mixture of what can be found on today's green sea and leatherback turtles. It's a combination that paid off for the plesiosaur. Although the tail skin suggests a smooth body, the scales 'along the trailing edges of the flippers undoubtedly fulfilled some functional role,' the team wrote, adding that the overall anatomy 'conferred a selective advantage for plesiosaurs during their protracted evolution as one of the most successful' ancient flippered reptiles.
