Gecko lizards can walk on water


This video says about itself:

Geckos can run across water

Geckos (Hemidactylus platyurus) have the ability to exceed the speed limits of conventional surface swimming, running across water at up to almost a meter a second using a unique mix of surface tension and slapping.

Credits: UC Berkeley/Roxanne Makasdjian/Stephen McNally/Pauline Jennings, Jasmine A. Nirody, Judy Jinn, Thomas Libby, Timothy J. Lee, Ardian Jusufi, David L. Hu, Robert J. Full.

Music: Horses to Water by Topher Mohr and Alex Elena courtesy of YouTube Audio Library

From the University of California – Berkeley in the USA:

Acrobatic geckos, highly maneuverable on land and in the air, can also race on water

Geckos combine surface tension with foot slapping to stay above water surface

December 6, 2018

Summary: Asian geckos were observed running over water at nearly a meter per second, as fast as on land. Lab experiments show how. They get support from surface tension but also slap the water rapidly with their feet. They also semi-plane over the surface and use their tail for stabilization and propulsion. They thus sit between insects, which use only surface tension, and larger animals, which run upright via foot slapping alone.

Geckos are renowned for their acrobatic feats on land and in the air, but a new discovery that they can also run on water puts them in the superhero category, says a University of California, Berkeley, biologist.

“They can run up a wall at a meter per second, they can glide, they can right themselves in midair with a twist of their tail and rapidly invert under a leaf running at full speed. And now they can run at a meter per second over water. Nothing else can do that; geckos are superheroes,” said Robert Full, a UC Berkeley professor of integrative biology.

Full is the senior author of a paper that will appear this week in the journal Current Biology describing four separate strategies that geckos use to skitter across the surface of water. First author Jasmine Nirody, a biophysicist at the University of Oxford and Rockefeller University, conducted much of the research with Judy Jinn, both as Ph.D. students at Berkeley.

According to Full, who discovered many of the unique maneuvers and strategies geckos employ, including how their toe hairs help them climb smooth vertical surfaces and hang from the ceiling, the findings could help improve the design of robots that run on water.

Nirody first became intrigued by geckos’ water-running behavior after co-author Ardian Jusufi, now a biophysicist at Max Planck Institute for Intelligent Systems and another former UC Berkeley Ph.D. student, noticed that geckos in the forests of southeast Asia could skitter across puddles to escape predators.

In fact, they are able to run at nearly a meter, or three feet, per second over water and easily transition to speeding across solid ground or climbing up a vertical surface. Geckos sprinting on the water’s surface exceed the absolute swimming speeds of many larger, aquatic specialists including ducks, minks, muskrats, marine iguanas and juvenile alligators, and are faster in relative speed than any recorded surface swimmer, other than whirligig beetles.

How, she wondered, do they do that?

Smaller animals like insects — spiders, beetles and water striders, for example — are light enough to be kept afloat by surface tension, which allows them to easily glide across the surface. Larger animals, such as swans during takeoff or the basilisk lizard, and even dolphins rising up on their tails, rapidly slap and stroke the water to keep above the waves.

“Bigger animals can’t use surface tension, so they end up pushing and slapping the surface, which produces a force if you do it hard enough,” Full said.

But the gecko is of intermediate size: at about 6 grams (one-fifth of an ounce, or the weight of a sheet of paper), they are too large to float above the surface, but too light to keep their bodies above water by slapping forces only.

“The gecko’s size places them in an intermediate regime, a middle ground,” Nirody said. “They can’t generate enough force to run along the surface without sinking, so the fact they can race across water is really surprising.”

In experiments with flat-tailed house geckos (Hemidactylus platyurus), common in south and southeast Asia, she discovered that they actually use at least two and perhaps four distinct strategies to run atop the water surface.

Surface tension is essential, she found, because when she applied a surfactant or soap to eliminate surface tension, the geckos were much less efficient: their speed dropped by half.

Even without surface tension, however, they can move using slapping, paddling movements with their four legs like larger animals. Leg slapping created air pockets that helped keep their bodies from being completely submerged, allowing them to trot across the water in much the same way they run on land.

But they also seem to use their smooth, water-repellent skin to plane across the surface, similar to hydroplaning but referred to as semi-planing, a technique used by muskrats.

Finally, they also use their tail to swish the water like an alligator, providing propulsion as well as lift and stabilization.

“All are important to some extent, and geckos are unique in combining all these,” Full said.

“Even knowing the extensive list of locomotive capabilities that geckos have in their arsenal, we were still very surprised at the speed at which they could dart across the water’s surface,” Nirody said. “The way that they combine several modalities to perform this feat is really remarkable.”

In the lab, she and her colleagues built a long water tank, placed the geckos on a plank and startled them by touching their tails. Using high-speed video, they were able to closely study the geckos’ techniques and estimate the forces involved.

This research was funded by the National Science Foundation and the Swiss National Science Foundation. Other co-authors of the paper are Thomas Libby and Timothy Lee of UC Berkeley and David Hu from Georgia Tech.

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Jurassic ichthyosaur was warm-blooded, new research


This 15 June 2018 video says about itself:

Ichthyosaurs 101 | National Geographic

Meaning “fish lizard” in Greek, the aptly-named ichthyosaur once dominated the world’s oceans for millions of years. Learn about these prehistoric marine reptiles and see how features, such as basketball-sized eyes and a vertical tail, helped the ichthyosaur secure a place at the top of the ancient food chain.

From the North Carolina State University in the USA:

Soft tissue shows Jurassic ichthyosaur was warm-blooded, had blubber and camouflage

December 5, 2018

An ancient, dolphin-like marine reptile resembles its distant relative in more than appearance, according to an international team of researchers that includes scientists from North Carolina State University and Sweden’s Lund University. Molecular and microstructural analysis of a Stenopterygius ichthyosaur from the Jurassic (180 million years ago) reveals that these animals were most likely warm-blooded, had insulating blubber and used their coloration as camouflage from predators.

“Ichthyosaurs are interesting because they have many traits in common with dolphins, but are not at all closely related to those sea-dwelling mammals,” says research co-author Mary Schweitzer, professor of biological sciences at NC State with a joint appointment at the North Carolina Museum of Natural Sciences and visiting professor at Lund University. “We aren’t exactly sure of their biology either. They have many features in common with living marine reptiles like sea turtles, but we know from the fossil record that they gave live birth, which is associated with warm-bloodedness. This study reveals some of those biological mysteries.”

Johan Lindgren, associate professor at Sweden’s Lund University and lead author of a paper describing the work, put together an international team to analyze an approximately 180 million-year-old Stenopterygius fossil from the Holzmaden quarry in Germany.

“Both the body outline and remnants of internal organs are clearly visible,” says Lindgren. “Remarkably, the fossil is so well-preserved that it is possible to observe individual cellular layers within its skin.”

Researchers identified cell-like microstructures that held pigment organelles within the fossil’s skin, as well as traces of an internal organ thought to be the liver. They also observed material chemically consistent with vertebrate blubber, which is only found in animals capable of maintaining body temperatures independent of ambient conditions.

Lindgren sent samples from the fossil to international colleagues, including Schweitzer. The team conducted a variety of high-resolution analytical techniques, including time-of-flight secondary ion mass spectrometry (ToF SIMS), nanoscale secondary ion mass spectrometry (NanoSIMS), pyrolysis-gas chromatography/mass spectrometry, as well as immunohistological analysis and various microscopic techniques.

Schweitzer and NC State research assistant Wenxia Zheng extracted soft tissues from the samples and performed multiple, high-resolution immunohistochemical analyses. “We developed a panel of antibodies that we applied to all of the samples, and saw differential binding, meaning the antibodies for a particular protein — like keratin or hemoglobin — only bound to particular areas,” Schweitzer says. “This demonstrates the specificity of these antibodies and is strong evidence that different proteins persist in different tissues. You wouldn’t expect to find keratin in the liver, for example, but you would expect hemoglobin. And that’s what we saw in the responses of these samples to different antibodies and other chemical tools.”

Lindgren’s lab also found chemical evidence for subcutaneous blubber. “This is the first direct, chemical evidence for warm-bloodedness in an ichthyosaur, because blubber is a feature of warm-blooded animals,” Schweitzer says.

Taken together, the researchers’ findings indicate that the Stenopterygius had skin similar to that of a whale, and coloration similar to many living marine animals — dark on top and lighter on the bottom — which would provide camouflage from predators, like pterosaurs from above, or pliosaurs from below.

“Both morphologically and chemically, we found that although Stenopterygius would be loosely considered ‘reptiles,’ they lost the scaly skin associated with these animals — just as the modern leatherback sea turtle has,” Schweitzer says. “Losing the scales reduces drag and increases maneuverability underwater.

“This animal’s preservation is unusual, especially for a marine environment — but then, the Holzmaden formation is known for its exceptional preservation. This specimen has given us more evidence that these tissues and molecules can preserve for extremely long periods, and that soft tissue analysis can shed light on evolutionary patterns, relationships, and how ancient animals functioned in their environment.

“Our results were repeatable and consistent across labs. This work really shows what we’re capable of discovering when we perform a multidisciplinary, multi-institutional study of an exceptional specimen.”

Many sea turtles at Costa Rican beach


This 25 November 2018 video says about itself:

A Mass Synchronized Nesting Event | Jaguar Beach Battle

The arribada finally begins on the Nancite Beach of Costa Rica, a mass synchronized nesting event for three days where tens of thousands of female Olive Ridley sea turtles return to the beach they were born to lay their own eggs.

Sauropods, the biggest dinosaurs, how big?


This 28 November 2018 video says about itself:

SAUROPODS: The Largest Dinosaurs. Size comparison.

Species included: Thecodontosaurus, Melanorosaurus, Plateosaurus, Nigersaurus, Riojasaurus, Amargasaurus, Shunosaurus, Opisthocoelicaudia, Spinophorosaurus, Isisaurus, Camarasaurus, Diplodocus, Brontosaurus, Apatosaurus, Turiasaurus, Brachiosaurus, Mamenchisaurus, Barosaurus, Argentinosaurus.

Dinosaur discoveries in Yunnan, China


This 30 November 2018 video says about itself:

This Chinese Region is a Treasure Trove of Dinosaur Discoveries

Yunnan province in China is a haven for dinosaur remains – especially the Lufeng area. To date, it has yielded 76 complete specimens of Lufengosaurus – a plant-eating dinosaur from the Jurassic era.