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Chile’s 1st full ichthyosaur fossil Earth’s only pregnant female found from 129-139 mn years ago

ScientiFix, our weekly feature, offers you a summary of the top global science stories of the week, with links to their sources.

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New Delhi: Researchers from Magallanes University have unearthed the fossilised remains of a four-metre-long pregnant female ichthyosaur, nicknamed “Fiona”, in Chile.

This is Chile’s first complete ichthyosaur fossil, and was unearthed from a melting glacier deep in the Patagonia area of the country. The intact remains were collected using a helicopter.

The ichthyosaur fossil contains several embryos and was first discovered in 2009, but extracted now. The expedition to retrieve the fossil lasted an intense 31 days.

The exceptional ichthyosaur is the only pregnant female of the era — between 129 and 139 million years ago — found and extracted on the planet.

The excavation will help to provide information on its species, on the palaeobiology of embryonic development, and on any disease that affected it during its lifetime. Read more.


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NASA’s InSight lander records largest quake on Mars

NASA’s InSight Mars lander has detected the largest quake ever observed on another planet. A temblor of an estimated magnitude of 5, occurred on 4 May, the 1,222nd Martian day of the mission.

This adds to the catalog of more than 1,313 quakes InSight has detected since landing on Mars in November 2018. The largest previously recorded quake had an estimated magnitude of 4.2, detected on 25 August last year.

InSight was sent to Mars with a highly sensitive seismometer to study the deep interior of the planet. As seismic waves pass through or reflect off material in Mars’ crust, mantle, and core, they change in ways that seismologists can study to determine the depth and composition of these layers.

What scientists learn about the structure of Mars can help them better understand the formation of all rocky worlds, including Earth and its Moon.

A magnitude 5 quake is a medium-size quake compared to those felt on Earth, but it’s close to the upper limit of what scientists hoped to see on Mars during InSight’s mission. Read more.

Water may have been present on Mars longer than thought

Scietnists at the Chinese Academy of Sciences have found evidence that water was present on Mars more recently than previously believed.

Earlier studies have suggested that parts of the Martian surface were covered with water up until approximately three billion years ago. The time since the water dried up on Mars is known as the Amazonia period. Data from the Chinese rover Zhurong indicates that water on Mars might have persisted longer than has been thought.

Zhurong has been traveling around in an impact crater on the Martian surface for approximately a year, analysing rocks.

The researchers compared data found in the rocks on Mars with rocks on Earth, and found that some of the rocks are hydrated minerals — that is minerals containing water.

They also found instances of layers of duricrust — consisting of a hardened accumulation of silica (SiO2), alumina (Al2O3), and iron oxide — that would have required a large amount of water either rising from below the surface or from a large quantity of melting ice.

The researchers suggest that water must have persisted on Mars longer than has been thought to account for the hydrated minerals on its surface — perhaps for much longer. They also suggest that the existence of such rocks on the surface hints at the possibility of ground ice. Read more.

Scientists revive light sensing neurons

Scientists have successfully been able to revive light-sensing neuron cells in organ donor eyes and restored communication between them.

Neurons in the central nervous system transmit sensory information as electrical signals. In the eye, specialised neurons known as photoreceptors sense light.

Researchers at the University of Utah and Scripps Research used the retina as a model of the central nervous system to investigate how neurons die — and found new methods to revive them.

They were able to wake up photoreceptor cells in the human macula, which is the part of the retina responsible for our central vision and our ability to see fine detail and color.

In eyes obtained up to five hours after an organ donor’s death, these cells responded to bright light, colored lights, and even very dim flashes of light.

While initial experiments revived the photoreceptors, the cells appeared to have lost their ability to communicate with other cells in the retina. The team identified oxygen deprivation as the critical factor leading to this loss of communication.

To overcome the challenge, the team procured organ donor eyes in under 20 minutes from the time of death and designed a special transportation unit to restore oxygenation and other nutrients to the organ donor eyes.

They also built a device to stimulate the retina and measure the electrical activity of its cells. With this approach, the team was able to restore a specific electrical signal seen in living eyes known as the “b wave.” It is the first b wave recording made from the central retina of postmortem human eyes. Read more.

Six new frog species discovered in Mexico

Scientists from the University of Cambridge, London’s Natural History Museum and the University of Texas at Arlington, have discovered six new species of frog, the size of a thumbnail, in the forests of Mexico, with one earning the distinction of Mexico’s smallest frog.

All six species are around 15mm long when fully grown. Adult males of the tiniest of these species grow to only 13mm.

The newly discovered species are known as ‘direct-developing’ frogs — rather than hatching from eggs into tadpoles like most frogs, they emerge from the eggs as perfect miniature frogs. And they’re so small that they’re right at the bottom of the forest food chain.

These frogs live in the dark, humid leaf litter of the forests, so there is still much to learn about how they socialise, or how they breed.

The study involved gathering almost 500 frog specimens from museums around the world, which had been collected in Mexico, and using new methods to categorise the relationships between them.

Using DNA sequencing, the team sorted the frogs into groups based on how similar their genes were. Then CT-scanning was used to create 3D models of the frogs’ skeletons, so that physical details could be compared. These two very different lines of evidence revealed six new species of frog. Read more.

(Edited by Poulomi Banerjee)


Also read: Scientists capture first-ever image of supermassive black hole at the centre of Milky Way


 

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