All of Your Teeth Evolved From a Single Ancestral Tooth in the Age of the Dinosaurs

iStock
iStock

Anyone who's received a root canal or a lecture from their dentist about flossing probably doesn't appreciate their teeth like they should. But our pearly whites are unlike any other structures in the body, and for that, they deserve some recognition.

In their new video, TED-Ed explains what exactly makes teeth unique. Unlike regular bones, teeth are made of two layers: a hard enamel coating and a strong dentin core. The combination of these two components makes teeth both hard and strong enough to endure a lifetime of wear and tear.

The tooth's tough composition isn't exclusive to humans. All mammals, whether they're meat-tearing cats or grass-munching cows, grow their teeth the same way, and they owe their teeth's existence to a common ancestor.

In the 19th century, paleontologist Edward Drinker Cope hypothesized that the tribosphenic molar, a tooth type that evolved during the dinosaur age, is the root of all modern mammalian teeth. With just a few genetic tweaks made over millennia, the tribosphenic molar has given way to the teeth used by carnivores, herbivores, and omnivores to process their food.

To learn more about the evolution and biology of teeth, check out the video from TED-Ed below.

[h/t TED-Ed]

Bizarre New Giant Salamander Species Discovered in Florida

There’s something in the water in Florida, but it’s not the swamp monster locals may have feared. According to National Geographic, scientists have discovered a new species of giant salamander called a reticulated siren, and you can find the 2-foot-long amphibian in the swamps of southern Alabama and the Florida panhandle.

Locals have long reported seeing a creature with leopard-like spots, the body of an humongous eel, and axolotl-like frills sprouting out of the sides of its head, but its existence wasn’t described in scientific literature until now. Researchers from Texas and Georgia recently published their findings in the journalPLOS ONE.

“It was basically this mythical beast,” David Steen, a wildlife ecologist and one of the paper’s co-authors, tells National Geographic. He had been trapping turtles at the Eglin Air Force Base in Okaloosa County, Florida, in 2009 when he caught one of the creatures by chance. After that encounter, the researchers set out to find more specimens.

Colloquially, locals have long been calling the creature a leopard eel. Because the reticulated siren only has two tiny front limbs, it's easy to mistake it for an eel. Its hind limbs disappeared throughout the course of millions of years of evolution, and it also lacks eyelids and has a beak instead of the teeth that are typical of other salamander species.

They belong to a genus of salamanders called sirens, which are one of the largest types of salamander in the world. The second part of the species’ name comes from the reticulated pattern seen on all of the individuals that were examined by researchers. The reticulated siren is also one of the largest vertebrates to be formally described by scientists in the U.S. in the last 100 years, according to the paper.

There are still a lot of unknowns about the reticulated siren. They lead hidden lives below the surface of the water, and they’re thought to subsist on insects and mollusks. Researchers say further study is urgently needed because there's a chance the species could be endangered.

[h/t National Geographic]

A Dracula Ant's Jaws Snap at 200 Mph—Making It the Fastest Animal Appendage on the Planet

Ant Lab, YouTube
Ant Lab, YouTube

As if Florida’s “skull-collecting” ants weren’t terrifying enough, we’re now going to be having nightmares about Dracula ants. A new study in the journal Royal Society Open Science reveals that a species of Dracula ant (Mystrium camillae), which is found in Australia and Southeast Asia, can snap its jaws shut at speeds of 90 meters per second—or the rough equivalent of 200 mph. This makes their jaws the fastest part of any animal on the planet, researchers said in a statement.

These findings come from a team of three researchers that includes Adrian Smith, who has also studied the gruesome ways that the skull-collecting ants (Formica archboldi) dismember trap-jaw ants, which were previously considered to be the fastest ants on record. But with jaw speeds of just over 100 miles per hour, they’re no match for this Dracula ant. (Fun fact: The Dracula ant subfamily is named after their habit of drinking the blood of their young through a process called "nondestructive cannibalism." Yikes.)

Senior author Andrew Suarez, of the University of Illinois, said the anatomy of this Dracula ant’s jaw is unusual. Instead of closing their jaws from an open position, which is what trap-jaw ants do, they use a spring-loading technique. The ants “press the tips of their mandibles together to build potential energy that is released when one mandible slides across the other, similar to a human finger snap,” researchers write.

They use this maneuver to smack other arthropods or push them away. Once they’re stunned, they can be dragged back to the Dracula ant’s nest, where the unlucky victims will be fed to Dracula ant larvae, Suarez said.

Researchers used X-ray imaging to observe the ants’ anatomy in three dimensions. High-speed cameras were also used to record their jaws snapping at remarkable speeds, which measure 5000 times faster than the blink of a human eye. Check out the ants in slow-motion in the video below.

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