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Image credit: Aziz Aboobaker, Edinburgh
Image credit: Aziz Aboobaker, Edinburgh

The Tardigrade’s Extraordinary Weirdness Continues

Image credit: Aziz Aboobaker, Edinburgh
Image credit: Aziz Aboobaker, Edinburgh

The mystery of the tardigrade—a.k.a. moss piglet, a.k.a. water bear—is one step closer to a solution. Scientists studying the microscopic animals' DNA say the tough, many-legged creatures may be distantly related to nematodes and other "wormy things." The researchers published their findings in the journal PLOS Biology.

Tardigrades are some of the strangest, most badass organisms on Earth. Don't be fooled by their tiny size—these animals are anything but delicate. They can survive in the most brutal conditions, from dehydration and starvation to burning heat, blistering cold, intense radiation, and even the vacuum of space.

How they pull off this near-invincibility is, naturally, a question of some interest among biologists (and to Mental Floss—links to our many articles about these amazing creatures are found throughout this story).

The authors of one 2015 study made headlines when they announced that one-sixth of the tardigrade's genetic blueprint had been swiped from bacteria and other organisms. This horizontal gene transfer (HGT) is not unheard of in nature, but other tardigrade experts, including a team at the University of Edinburgh, felt that 17.5 percent seemed suspiciously high, even for a maverick like the tardigrade.

The skeptics were right. Additional investigation into the tardigrade genome confirmed the presence of a few horizontally transferred genes. Just a few.

HGT aside, there's still plenty to discover in the tardigrade's genes. Tardigrades have been tardigrades for hundreds of millions of years. No fossils remain from their early days to tell us what they might have been before. We don't really know where they came from, evolutionarily speaking, or who their relatives are.

To find out, Edinburgh researcher Mark Blaxter and his colleagues picked apart the genomes of two tardigrade species, Ramazzottius varieornatus and Hypsibius dujardini. They found something unexpected: The armored, many-legged tardigrades seemed more closely related to worms than to insects.

If these findings are accurate, Blaxter told Mental Floss in an email, they challenge the very structure of the Panarthropoda family tree, which assumes "the leggy moulting animals are more closely related to each other than they are to wormy things like nematodes."

But he notes that there's lots more research to be done before issuing that challenge: "We have only looked at a tiny fraction of the 10 or more million species on Earth. Every new group, and possibly every species, will have something exciting in it we haven't seen before, and didn't imagine."

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Why Can Parrots Talk and Other Birds Can't?
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If you've ever seen a pirate movie (or had the privilege of listening to this avian-fronted metal band), you're aware that parrots have the gift of human-sounding gab. Their brains—not their beaks—might be behind the birds' ability to produce mock-human voices, the Sci Show's latest video explains below.

While parrots do have articulate tongues, they also appear to be hardwired to mimic other species, and to create new vocalizations. The only other birds that are capable of vocal learning are hummingbirds and songbirds. While examining the brains of these avians, researchers noted that their brains contain clusters of neurons, which they've dubbed song nuclei. Since other birds don't possess song nuclei, they think that these structures probably play a key role in vocal learning.

Parrots might be better at mimicry than hummingbirds and songbirds thanks to a variation in these neurons: a special shell layer that surrounds each one. Birds with larger shell regions appear to be better at imitating other creatures, although it's still unclear why.

Learn more about parrot speech below (after you're done jamming out to Hatebeak).

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Extinct Penguin Species Was the Size of an Adult Human
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A penguin that waddled across the ice 60 million years ago would have dwarfed the king and emperor penguins of today, according to the Associated Press. As indicated by fossils recently uncovered in New Zealand, the extinct species measured 5 feet 10 inches while swimming, surpassing the height of an average adult man.

The discovery, which the authors say is the most complete skeleton of a penguin this size to date, is laid out in a study recently published in Nature Communications. When standing on land, the penguin would have measured 5 feet 3 inches, still a foot taller than today’s largest penguins at their maximum height. Researchers estimated its weight to have been about 223 pounds.

Kumimanu biceae, a name that comes from Maori words for “monster" and "bird” and the name of one researcher's mother, last walked the Earth between 56 million and 60 million years ago. That puts it among the earliest ancient penguins, which began appearing shortly after large aquatic reptiles—along with the dinosaurs—went extinct, leaving room for flightless carnivorous birds to enter the sea.

The prehistoric penguin was a giant, even compared to other penguin species of the age, but it may not have been the biggest penguin to ever live. A few years ago, paleontologists discovered 40-million-year-old fossils they claimed belonged to a penguin that was 6 feet 5 inches long from beak to tail. But that estimate was based on just a couple bones, so its actual size may have varied.

[h/t AP]

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