(Left to right): Scinceside/Wikimedia; Matthew Jacobs; University of Cambridge

Top stories: Mosquito-killing guppies cause ecological trouble, fresh evidence for Planet Nine, and the first fossilized dinosaur brain

Ecologists raise alarm over releases of mosquito-killing guppies

For decades, the little guppy Poecilia reticulata has been championed as a mosquito fighter and dumped into ponds and ditches to eat up the insect’s larvae. But among scientists, it has a different reputation—as an invasive species with a remarkable ability to reproduce and spread. In a paper published online this week in Biology Letters, a group of ecologists argues that the guppies—and other nonnative fish used for mosquito control—haven’t actually proven very effective mosquito fighters, but are known to pose ecological risks.

Blue leaves help plants get extra energy from sun

A team of researchers from the United Kingdom reports this week in Nature Plants that it has discovered a species of shade-dwelling begonia called Begonia pavonina that arranges light-absorbing components in its leaves to boost their light absorption. Typically, chloroplasts contain membrane-bound compartments called thylakoids that stack atop one another in a somewhat haphazard arrangement. In B. pavonina, this stacking is far more regular, creating what are known as photonic crystals. These crystalline arrays strongly reflect blue light, giving the leaves an iridescent glow, and absorbing as much as 10% more energy than other low-lying forest dwellers.

Objects beyond Neptune provide fresh evidence for Planet Nine

Since January, scientists have been chasing Planet Nine: a distant hypothetical world that could have 10 times the mass of Earth and explain the peculiarly clustered orbits of six icy bodies beyond Neptune. Studies presented last week at a meeting of the American Astronomical Society in Pasadena, California, are giving astronomers in search of Planet Nine extra encouragement. Researchers have found another three transneptunian objects that, like the first six, may corroborate Planet Nine’s existence and help narrow down its putative orbit. The influence of the unseen giant could also explain the strange orbits of two more objects, perpendicular to the plane of the solar system. And it might explain why the sun is tipped slightly on its axis, astronomers say.

MERS biosafety breach

A researcher from the Pasteur Institute Korea in Seoul brought samples taken during the country's outbreak of Middle East respiratory syndrome on an intercontinental flight last year without the appropriate paperwork, hoping to get them studied at the Pasteur Institute in Paris. Both institutes have acknowledged the incident and say the trip never put anyone in danger, because the samples had undergone a standard treatment that would have killed any living virus. A review confirmed the samples were inactivated, and as a result, they were noninfectious and did not need any special approval from the airline to be taken onto the flight.

A dinosaur’s brain, preserved in a pebble

A decade ago, a fossil hunter was combing the beach in southeastern England when he found a strange, brown pebble. The surface of it caught his eye: It was smooth and strangely undulating, and also slightly crinkly in some places. That oddly textured pebble, scientists report at the Society for Vertebrate Paleontology meeting, is actually an endocast—an impression preserved in the rock—that represents the first known evidence of fossilized brain tissue of a dinosaur (likely a close relative of Iguanodon, a large, herbivorous type of dinosaur that lived about 133 million years ago). The structure of the brain, studied with scanning electron microscopes, reveal similarities to both birds and crocodiles. It’s the first known evidence of such a dinosaur brain—but now that they know to look for it, the researchers say, they might go back and look at other endocranial casts of dinosaurs to see whether they might contain traces of other such structures.

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