The 305 million-year-old fossil of an arachnid discovered in France has revealed the progressive evolution of modern-day spiders. Russell Garwood, UK’s University of Manchester paleontologist, says the creatures is “not quite a spider, but it’s very close to being one.”

As reported in National Geographic, the oldest known fossil of a spider was found in the French coal seam, Montceau-les-Mines, and is 305 million years old. Researchers say the fact that the fossilized arachnid, called Idmonarachne brasieri, is from the same time period reveals that these ancient spiders lived alongside creatures that were almost spiders. It is a “spider cousin,” filling a previously existing gap in spider evolution.

Although the fossil was discovered in the 1980s, its mysteries were only recently unlocked. The front half of the fossil was buried in rock, but x-ray computed tomography revealed its mysteries for Garwood and his team, who were able to create a 3D model of Idmonarachne. They were able to look inside the rock and make out the arachnid’s walking legs and mouthparts, which are necessary for identifying the species and genus of this type of creature.

The 1.5 cm fossil shows spiderlike legs and mouthparts, but lacks spinnerets, which modern spiders use to spin silk. Spider relatives who lived prior to Idmonarachne were able to make silk to line their burrows and protect their eggs but could not build webs. Without spinnerets the arachnid cannot be called a spider.

Idmonarachne also had a segmented abdomen rather than fused abdomen like a true spider. Garwood said, “We’re looking at a line of spiderlike arachnids that haven’t survived but must have split off before 305 million years ago.”

Little of arachnids’ early history is known, as very few rocks from at least 420 million years ago are available, which is the time these creatures first emerged onto land. Arachnids were actually among the first land-dwellers, but  figuring out their evolution through DNA is difficult because they diversified so early, leaving few evolutionary changes in their genes that are traceable.

Garwood told the National Geographic this fossil is the most closely related thing to a spider that has been found that is not actually a spider. The researchers are planning further studies of other fossils to continue to increase their understanding of spiders. One question is how scorpions and harvestmen are related to arachnids and spiders.

The number of fish in the world’s oceans has been decimated by overfishing, and current fishery regulations setting limits on the amount that can be caught are not helping. According to a new report published Monday in the Proceedings of the National Academy of Sciences, the solution is cooperation by fishermen around the world, which scientists now say would leave plenty of fish to catch, while still doubling the number of fish left by the year 2050.

Scientists from the University of Washington, the University of California – Santa Barbara and the Environmental Defense Fund compiled a database that included over 4,500 worldwide fisheries, and, after using a number of bioeconomic models, found that productivity and health can coexist in the world’s fisheries. Environmental Defense Fund’s chief oceans scientist Douglas Radar, one of the study’s lead authors, said, “It is not a tradeoff between the needs of fishermen and the needs of fish.”

The study explains that sound management reforms to global fisheries “could generate annual increases exceeding 16 million metric tons (MMT) in catch, $53 billion in profit, and 619 MMT in biomass relative to business as usual. We also find that, with appropriate reforms, recovery can happen quickly, with the median fishery taking under 10 [years] to reach recovery targets.”

Sound too good to be true? Maybe not, if fishermen will only adopt sustainable fishing practices that include a “catch share” model of management of the world’s fisheries. In these systems, regulators figure out how many fish can be caught without hurting future fish populations. That amount is then divided into shares that are distributed to individual fishermen, giving each a set amount of fish they can catch in a year.

Ray Hilborn, marine biology and fishers science professor at the University of Washington, who is a co-author of the study, says “If you can reform fisheries and eliminate their competitive nature, there’s enormous room for profits, catch and abundance.

This approach is different than the quotas set in traditional fishing regulations for the number of fish that can be caught and limit the number of days a fleet can fish, as well as the equipment they can use. The study authors say this leads to a free-for-all in which individual fishermen try to grab the most they can before regulators declare that the quota has been met, ending the fishing season. This system causes overfishing and leads to unpredictability in the business.

Amanda Leland, Environmental Defense Fund’s senior vice president for oceans said, “When you give fishermen a secure share of the catch and they know on January 1 the total catch for the year, they slow down their fishing, they burn less fuel, they cut their costs, they go when the weather is good, and they are able to provide a much more predictable supply.”

However, there is little sign that Asia would be willing to adopt sustainable fishing. Just Wednesday, Singapore’s daily newspaper Today reported that Southeast Asian countries are angry about illegal fishing in their waters by Chinese trawlers. There are also skeptics, once the shares of available fish are given out it could result newcomers waiting years to enter the system.

Hilborn responded to this criticism, saying, “Limiting access to fishing is the primary tool we’ve had to improve fisheries. In very few fisheries can anyone go fishing who wants to go fishing.”

Scientists have recently found a fossilized skull from a Siberian unicorn that shows the 9,000-pound creatures lived as recently as 29,000 years ago, and actually shared the earth with humans.

This unicorn looked nothing like the fairy tale version. Elasmotherium sibiricum was shaggy and looked like a modern rhinoceros, but with a huge horn. It was actually closer to wooly mammoth size than being similar to a horse, about 6.5 feet tall and 15 feet long. Its single horn was much longer than that of a modern rhino. It was very hairy as well. Not a pretty picture.

The skull was found in Kazakhstan. Researchers from Tomsk State University dated it via radiocarbon dating techniques. How the owner of the skull died is unknown but they believe it was a very old male, based on the condition and size of the skull.

The Siberian unicorn first appeared in the fossil record about 2.5 million years ago, and was thought to have disappeared 350,000 years ago. The big question for researchers is how this unicorn was able to exist so much longer than the ones that died out so long ago. Team member Andrey Shpanski said, “most likely the south of Western Siberia was a refugium, where this rhino persevered the longest in comparison with the rest of its range. There is another possibility that it could migrate and dwell for a while in more southern areas.

The study of the newly-discovered unicorn skull was published in the American Journal of Applied Sciences.

Photo from Wikimedia Commons, public domain

Scientists say increasing ocean temperatures are causing coral bleaching in the Great Barrier Reef that has damaged or killed 95 percent of the northern reefs. An aerial survey found that, in the worst examples of bleaching in recorded history, 520 sites in the 2,500-kilometer-long stretch of delicate coral in north-east Australia have been “fried.” Long stretches have lost their vivid colors, turning snow-white from bleaching that began 6 months ago.

Terry Hughes, from James Cook University, said “this will change the Great Barrier Reef forever.” He said it is too early to tell just how much of the bleached coral will die, but he expects about half will perish in the next month or so. In their survey only four reefs were unaffected.

Hughes said that the current situation is unprecedented in how precarious it has become. Severe El Nino events are happening every few years that are triggering bleaching events, and “it wasn’t always like that.”

An El Nino weather pattern brought the temperature spike that triggered the bleaching. That spike combined with warmer water from climate change that is killing the tiny marine algae that are needed for the health and color of the coral. Warming temperatures are a major threat to corals around the world, according to experts. Rising sea temperatures affect the skeletal growth of the corals, as they expel the colorful algae that helps them survive as a defensive mechanism.

The Great Barrier Reef is home to more than 400 coral species and 1,500 fish species, and is a World Heritage Site. According to UNESCO, if only one coral reef can be chosen for the World Heritage List it will be the Great Barrier Reef. Now the question is whether it should be listed as “in danger.” Environmentalists have been raising concerns about the Great Barrier Reef for some time.

Hughes cited a prior bleaching event that occurred in 2002, but placed only 18 percent of reefs into the same damages seen today.

Comet 252P/LINEAR brightened suddenly a few weeks ago, making it 100 times brighter than expected, resulting in viewing opportunities this week for the Northern Hemisphere, starting today. The comet was visible with the naked eye in the Southern Hemisphere last week. In the Northern Hemisphere binoculars will most likely be needed, but viewing is possible.

Kelly Beatty, Senior Editor of Sky & Telescope, said “Don’t expect Comet LINEAR to be obvious with a long tail. Its light isn’t concentrated in a single point but instead is spread out in a soft round glow, larger than the Moon but many thousands of times dimmer.”

Astronomers are not sure how long LINEAR will be visible. It made its closest pass to Earth on March 21, and is now moving away. The best time to view it is about 90 minutes before the sun rises. It will be low in the southern sky, moving quickly north above the tail of the Scorpio constellation. It should be moving between Sagittarius and Scorpius.

Viewers may also want to triangulate the comet’s location with the planets Saturn and Mars, along with the star Antares. On March 31 the comet will be seen climbing to the left of the trio of bodies, roughly along a line connecting Saturn and Antares.

LINEAR’s green color is due to its chemical composition, which is less common than the usual white. When looking for the comet, look for green, not white.

The comet is small – only about 1 kilometer in diameter. It is only visible because it happens to be passing close to earth, and because it has brightened so much. Even so, it will be difficult to spot with the naked eye, especially with the brightness of the Moon this week. Binoculars or a small telescope will help, as will moving to a dark location away from neighborhood and city lights.

The Hubble Space Telescope has made a new discovery – a star that is 250 times larger than the Earth’s sun. It is so large that it is leaving scientists without an explanation as to how it could have gotten that big.

Astronomers had previously thought they knew how big stars could be, but those beliefs were nowhere near the size of the star known as R136a1. Eight other stars in the same cluster have masses more than 100 times larger than our sun, and astronomers can’t figure out how so many ultra-massive stars could be so close together.

The explanation to the unexplained mystery lies in how stars form. They start from a swirling gas cloud that begins to accumulate more gas by gravity generated by denser regions of the cloud that are formed by gas and dust. Once there is enough gas, the pressure becomes great enough for the gas to ignite, forming a star.

Once the gas ignites, a stellar wind is created that blows back outside gas, which stops further accumulation and should stop the star from getting any bigger at that point. The question is how nature can form a star so much bigger than our sun.

Scientists think it might be possible for two stars to merge, but they would have to get close enough and pass in exactly the right configuration. Otherwise they would just be caught in each other’s gravity and orbit each other in which is called a binary system. Approximately half of all known stars are in such a situation.

Another theoretical model has the stars in a binary system merging. Still, many such mergers would be needed to explain the size of R136a1.

The question would not even have been possible before the advent of the Hubble, which is the best detecter of ultraviolet light that present day scientists have. Massive stars burn very hot through nuclear fusion – the bigger the star, the more pressure at its center and the more nuclei fusing together. These hotter temperatures cause the massive stars to emit excessive amounts of ultraviolet light, which the Hubble’s imaging spectrograph can see.

R136a1 is 165,000 light years away from earth, and is the largest star ever discovered. It is located in the Large Magellanic Cloud, which is a nearby dwarf galaxy orbiting the Milky Way. The stars in this cluster are fairly young – only about 2 million years, compared to earth’s sun at 4.5 billion years. It is an exceptionally hot star, with estimated surface temperatures of around 95,000F, almost 10 times hotter than our sun.