Africa’s deadliest rapids give birth to new fish species

The world’s largest and deadliest rapids are also crucibles of life. According to a new study, the final stretch of Africa’s Congo River—which packs five times the water flow of the Mississippi River into just 320 kilometers—has likely given birth to several new fish species since it formed some 5 million years ago. That’s impressive, because even though scientists have long known that geographical features like mountains and rivers can isolate animal populations—eventually giving rise to new species—rushing water is typically not thought to be the culprit. To find out just how different the fish of Congo’s Inga Rapids and nearby waters were, evolutionary biologists captured about 50 rock-dwelling fish known as cichlids from the genus Teleogramma. They then examined them for morphological differences and sequenced about 2% of their DNA. What they found surprised them: Just as these waters have been so deadly to people—no one had successfully run the rapids until 6 years ago—they can also be deadly to fish that try to navigate through them. Because the tumultuous currents cut groups of fish off from one another, they evolve independently and, eventually, become new species. In the new study, all known and potentially new species were separated by rapids or other hydrological features, the scientists report this month in Molecular Ecology. Two of the species live just across the river from each other, a mere 1.5 kilometers. Altogether, researchers have used DNA differences to confirm the existence of four species, including a new one they named after former U.S. President Barack Obama. But there seem to be at least two other species there as well, swimming in the eddies.

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This strange mineral grows on dead bodies and turns them blue

If you were to get up close and personal with Ötzi the Iceman – the 5,000-year-old mummy of a tattooed , deep-voiced man who died and was frozen in the Alps – you’d notice that his skin is flecked with tiny bits of blue. At first, it would appear that these oddly bluish crystal formations embedded in his skin are from freezing to death or some other sort of trauma, but it’s actually a mineral called vivianite (or blue ironstone) and it happens to form quite often on corpses left in iron-rich environments. For Ötzi, the patches of vivianite are from him resting near rocks with flecks of iron in them, but other cases are way more severe. According to Chris Drudge at Atlas Obscura , a man named John White was buried in a cast iron coffin back in 1861. During those days, coffins often had a window for grieving family members to peer inside even if the lid was closed during the funeral. Sometime after he was buried, that window broke, allowing groundwater to come inside the

It's Official: Time Crystals Are a New State of Matter, and Now We Can Create Them

Peer-review has spoken. Earlier this year , physicists had put together a blueprint for how to make and measure time crystals - a bizarre state of matter with an atomic structure that repeats not just in space, but in time, allowing them to maintain constant oscillation without energy. Two separate research teams managed to create what looked an awful lot like time crystals back in January, and now both experiments have successfully passed peer-review for the first time, putting the 'impossible' phenomenon squarely in the realm of reality. "We've taken these theoretical ideas that we've been poking around for the last couple of years and actually built it in the laboratory," says one of the researchers , Andrew Potter from Texas University at Austin. "Hopefully, this is just the first example of these, with many more to come." Time crystals are one of the coolest things physics has dished up in recent months, because they point to a

The Dark Side Of The Love Hormone Oxytocin

New research shows oxytocin isn't the anti-anxiety drug we thought it was. Oxytocin, the feel-good bonding hormone released by physical contact with another person, orgasm and childbirth (potentially encouraging monogamy ), might have a darker side. The love drug also plays an important role in intensifying negative emotional memories and increasing feelings of fear in future stressful situations, according to a new study. Two experiments performed with mice found that the hormone activates a signaling molecule called extracellular-signal-related kinases (ERK), which has been associated with the way the brain forms memories of fear . According to Jelena Radulovic, senior author on the study and a professor at Northwestern University's medical school, ERK stimulates fear pathways in the brain's lateral septum, the region with the highest levels of oxytocin. Mice without oxytocin receptors and mice with even more oxytocin receptors than usual were placed in

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