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."

10 Terrifyingly Huge Birds You Should Know

AndreaWillmore/iStock via Getty Images
AndreaWillmore/iStock via Getty Images

They’re gigantic, they’re often defensive, and you wouldn’t want to run into them in a zoo after hours. Meet a few of the world’s biggest birds with attitude, from flightless giants to modern-day pterodactyls.

1. Ostrich

Everyone knows that the ostrich is the world’s biggest bird, weighing an average of 230 pounds and standing 7 feet tall (and some individuals can grow up to 9 feet). They can also chase you down: Ostriches are the fastest species on two legs, with a top speed of about 43 mph. They can maintain a swift 30 mph pace for 10 miles, making them the marathon champs of the avian world.

2. Southern Cassowary

Often called the most dangerous bird on Earth, in addition to being one of the planet’s biggest birds, the southern cassowary is roughly 150 pounds of mean. On each foot is a 5-inch claw that cassowaries use to defend themselves. At least two people have been kicked to death by cassowaries, the most recent being a Florida man who unwisely kept one of the birds as a pet.

3. Emu

Emu with eggs
JohnCarnemolla/iStock via Getty Images

Like a smaller, shaggier ostrich, the 5- to 6-foot emu is the second-largest bird on Earth (as well as a goofy spokesbird for insurance). During the breeding season, female emus fight enthusiastically over unattached males. But the results of this mating ritual are impressive: clutches of forest-green, oval eggs that resemble giant avocados.

4. Greater Rhea

This flightless bird is named for the Titan goddess Rhea, who gave birth to all of the Olympian gods and goddesses in Greek mythology. At up to 5 feet tall and 66 pounds, the greater rhea may not seem like as much of a terror as the ostrich. But it gathers in massive flocks of up to 100 birds during the non-breeding season, so watch out if you happen to be in its South American habitat.

5. Dalmatian Pelican

Dalmatian pelicans
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How scary can a pelican be, you ask? When it stands almost 6 feet tall, weighs 33 pounds, and has a wingspan of 9 feet—all traits of the Dalmatian pelican—it's pretty petrifying. These scruffy-feathered monsters, native to Europe and Asia, breed in colonies of up to 250 pairs and can gulp impressive mouthfuls of fish in one go.

6. Mute Swan

One of the heaviest flying birds, mute swans look harmless as they glide over ponds, lakes, and rivers. But mute swans are far from silent when defending their families and territory. Male swans warn interlopers that they’re getting too close with a hiss, then can launch a straight-up assault, bashing the intruder with their wings. They’ll even attack kayakers, canoeists, and people just minding their own business.

7. Andean Condor

Andean condor
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This freakishly big vulture isn’t satisfied with just any carrion—it prefers large carcasses like cattle and deer for dinner. Maintaining its average weight of 25 pounds requires a lot of calories, after all. Its wingspan is slightly less than its northern cousin, the California condor, but it still reaches a dramatic 9 to 10 feet.

8. Cinereous Vulture

Another big bird with a 10-foot wingspan, this Old World vulture has excellent vision to spot carrion while it flies, and a featherless head that resists the accumulation of gore when it feeds. Though it’s intimidating to look at, the cinereous vulture plays an important role in its ecosystem by cleaning up roadkill and other dead animals.

9. Marabou Stork

Marabou stork
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As if its red-tinged wattle, black back, and dagger-esque bill weren’t alarming enough, the marabou stork is sometimes called the “undertaker bird” thanks to its Dracula-like appearance. It also eats other birds. The largest verified wingspan on a marabou stork measured 10.5 feet, though unverified reports cited a specimen with 13.3-foot span.

10. Shoebill

Shoebill storks may not be the tallest, heaviest, or widest-winged birds, but just look at that death stare. On top of having a nutcracker for a face, the 5-foot-tall shoebill leads a fearsome lifestyle. It stands absolutely still for hours to hunt prey, watching for lungfish or baby crocodiles, then spreads its wings and collapses over it while trapping the target in its bill.

Scientists Capture Video of Deepstaria, a Rarely Seen, Shapeshifting Jellyfish

OET/NautilusLive
OET/NautilusLive

Millions of years of evolution taking place beneath the sea's surface have produced some bizarre animals. Jellyfish are among the oldest—and strangest—of the bunch. Some have "transient" anuses that only form when necessary, and others can renew their life cycles indefinitely. Little is known about Deepstaria, a jellyfish recently spotted by the crew of the Nautilus research vessel in the central Pacific Ocean, but as the video below shows, it's no less unusual than other species of jellyfish.

As Live Science reports, scientists aboard the Nautilus were scanning the seafloor about halfway between the U.S. and Australia when they spotted a spooky-looking creature hovering in front of them. It soon became clear that cosplaying a ghost wasn't all it could do. The jelly unfurled its sheet-like bell to reveal a geometric mesh membrane used to distribute nutrients throughout its body—a telltale sign of Deepstaria. It spends the rest of the video putting on a show for its guests, transforming from something resembling a crumpled plastic bag to a billowing blanket shape.

Deepstaria enigmatica was discovered by the Jacques Cousteau-designed Deepstar 4000 submersible—the vessel the species is named after—in the 1960s. It's only been spotted about a dozen times in the years since, and many details of how it lives remain a mystery to researchers.

Deepstaria's most distinctive feature is its massive, flowing bell. It lacks the tentacles most jellyfish use to wrangle prey, and scientists suspect it instead uses its bell as a net when hunting. The specimen captured in this video appears to be harboring a stowaway: a bright-red, living isopod suspended inside the bell. It isn't clear if the creature hitched a ride on purpose to evade more ferocious predators, if it's some type of parasite, or if it's the jellyfish's lunch.

With so many undiscovered and understudied species living in the sea, the Nautilus research vessel is frequently stumbling upon extraordinary examples of ocean life. In 2016 alone, it recorded footage of a googly-eyed stubby squid and a mysterious purple orb.

[h/t Live Science]

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