See the rest of TIME’s Top 10 of Everything 2013 lists here

10. The Carnivorous Olinguito

Mark Gurney / Smithsonian

If you think it’s hard to tell a chimpanzee from a bonobo, try distinguishing the new, carnivorous olinguito from all other olinguitos—tree-dwelling mammals of the Amazon cloud forest related to common raccoons. So closely does the reddish-brown animal with its deceptively cuddly appearance and its decidedly un-cuddly claws resemble its already identified cousins, that the preserved samples of the animal’s pelts which were long stored in U.S. museums were consistently mislabeled as common olinguitos. The Smithsonian Institution even reports that some of the animals may have been kept in American zoos in the 1960s, raising suspicion only because they never seemed to mate—at least not successfully—with others of their ostensible kind. But in 2013, the Smithsonian’s curator of mammals announced both anatomical and genetic evidence that conclusively carved out a new species. Not only does this earn the animals an entry in the taxonomy books, it may at last get the captive ones a cage with the right kind of mate. Happy trails you nocturnal imps, you.

9. Giant Amazon Freshwater Arapaima

Paulo Whitaker / Reuters

For every animal family that has hundreds of species, there are others that have only a few—or even just one. That was the case with the sleek, silvery, 7. ft. (2.1 m) Amazon fish known as the araipama, a favorite source of protein for local fishermen. In the middle of the 19th century, taxonomists thought they had identified four species, but by the 1860s, the differences among them were seen as trivial enough that they were collapsed back into a single one. Modern-day biologist Donald Stewart of the State University of New York looked more closely at specimens of the fish as well as at the old research and decided that nope, the first guess—four species—was correct. And in 2013, he identified a fifth one, physically distinguished from the others by only a few subtle features, including slightly different coloration and an elongated sinus cavity. The formal designation of the new species is less important than the problems it potentially poses. Araipama are now being raised and farmed, and farmed fish have a tendency to escape and become wild fish, sometimes crowding out native species they wouldn’t normally encounter. Stewart recommends caution in any more farming of arapaima until their species and behaviors can be better understood.

8. The Cape Melville Shade Skink

Conrad Hoskin / AFP / Getty Images

Australia was generous with the exotic animals this year, offering up the wonderfully named Cape Melville Shade Skink, a gold-colored, insect-eating lizard, which represents one more skink species in a family that already includes 1,500 others. But the Cape Melville entry is special, not only for its fetching color, but for its exuberance. Mot skinks stay close to the ground, hunting their buggy prey among the leaf litter. The Cape Melville skink leaps about on rock-and-moss fields. That’s usually a good way to get yourself eaten, but this species must know what it’s doing: it’s been around for about half a billion years.

7. Leaf-Tailed Gecko

Conrad Hoskin / Reuters

You probably wouldn’t want to be 8 inches long, have a tail shaped like a leaf and no eyelids to speak of, requiring you to lick your eyeballs clean every now and again. But if you were, you’d have been famous this year, because you’d be the Saltuarius eximius, the newest member of the leaf-tailed gecko family, discovered in northern Australia. Saltuarius is a hanger-on from an ancient era, dating back to the time 510 million years ago when Australia was part of a larger southern landmass known as Gondwana. The proto-continent is long gone, but some of its earliest inhabitants apparently remain and the rock-toned exquisitely camouflaged Saltuarius is one of the nicest. Patrick Couper, curator of reptiles and frogs at Queensland Museum, called the new critter, “the strangest new species to come across my desk in 26 years working as a professional herpetologist.” High praise from a scientist who clearly knows.

6. The Carolina Hammerhead

William Driggers

To answer the question you may or may not have been asking but have every right to ask: No, there is no animal uglier than a hammerhead shark. Seriously, what’s that head all about? Well, make room for one more—the Sphyrna gilbert, a new species of hammerhead shark that measures 10 to 13 ft. (3 to 4 m) fully grown, and has the one advantage of not being terribly aggressive. The species, informally known as the Carolina hammerhead after the U.S. coastal waters in which it was found, took some study, since it looks so similar to its cousin, the Scalloped hammerhead. There are some genetics differences between the two, but the only real physical difference is that the new fish has ten fewer vertebrae—something impossible to detect simply by looking. The head—its far more salient feature—remains regrettably the same.

5. Glow-in-the-Dark Cockroach

Peter Vrsansky & Dusan Chorvat

Sorry cockroaches, you don’t get to be any less disgusting just because you master a nifty new trick like glowing in the dark. OK, maybe you get to be a little less disgusting, but only because your shape and your glow spots make you look like a cute, bug-eyed egg. Still, the Luchihormetica luckae, which was identified this year, manages to undo any good will it earns. For starters, the creature it’s trying to mimic with its stay-away nocturnal shimmer is the toxic click beetle, which achieves the seemingly impossible task of being even lower than the roach on the ladder of appeal. And those cute, glowing eye spots? They’re made by pits in the animal’s skin filled with fluorescent bacteria.

4. NASA’S New Microbe

JPL-Caltech / NASA

NASA keeps looking for new species of microbes on Mars, but what it didn’t expect was to find one in a clean room at the Kennedy Space Center. As their name suggests, clean rooms are, you know, clean, which not only keeps dust out of spacecraft, but prevents terrestrial organisms from hitching a ride on them and contaminating other worlds. Scientists regularly sample the air and surfaces in the rooms to check for spotlessness, and at Kennedy, they found a bacterium they’d never seen before, the berry-shaped Teriscoccus phoenicis. As it turns out, the only other place in the world the microbe has been identified is in a European Space Agency clean room in French Guiana. And no, no, no, that does not mean the bugs are extraterrestrial. What it means is that they require exceedingly little to eat and, unlike most other microbes, can thus get by in so nutrient-poor an environment. A related species has also been found in only two places: yet another clean room in Florida and a bore hole in a Colorado molybdenum mine, 1.3 mi. (2.1 km) underground.

3. New Turkish Scorpion

Ersen Aydın Yağmur

You’ve surely heard the fable of the scorpion that asks the turtle to give it a lift across a river. The turtle demurs, saying that the scorpion would just sting him en route. The scorpion answers that he’d never do such a thing since they’d both sink. The turtle, finding that reasoning hard to argue with, agrees—whereupon, midway across the river, the scorpion does administer a fatal sting. “Why did you do that?” the turtle asks as it starts to sink. “It’s in my nature,” his passenger says with a scorpion shrug. That’s all by way of saying that the world has at least one more species of beast you shouldn’t trust, now that researchers working in southwest Turkey have announced the discovery of a new type of scorpion, known as the Euscorpius lycius. It’s as creepy-looking as any scorpion, as poisonous as any scorpion and as foul-tempered as any scorpion. But there’s not much to be afraid of. Just an inch or so across, it administers a sting that would cause you little more distress than a mosquito bite. Good news for us—bad news for the much smaller critters that cross its fearsome path.

2. Panthera Blythae

Mauricio Anton / AP

Being extinct is no reason not to make news, which is something a newly discovered species of great predatory cat, which last prowled the Earth 4.4 million years ago, proved this year. The Panthera blythae, discovered in Tibet, easily predates the previous big-cat record holder, which lived in Tanzania 3.7 million years ago. The new beast had a broad forehead that investigators compare to that of a modern snow leopard, but at 50 lbs. (27 kg), it was comparatively small, about the size of a modern clouded leopard. Still, like all big cats, it was clearly built for the kill. One of its most noteworthy features was its large teeth, which the investigators noticed were extremely heavily worn. They didn’t get that way on salads.

1. T. Rex’s Great Uncle

Mark Loewen

Just what the other animals of the prehistoric world needed—ten million extra years of living with the Tyrannosaurus rex family. That, however, appears to be how things were, after paleontologists in southern Utah announced the discovery of what they described as sort of a “great uncle” of the T. rex, which lived 80 million years ago—pushing the line way back from the 70 million year starting point previously assumed. The new tyrant king was a bit smaller than its fabled grand nephew, but that would have been little comfort to Cretaceous-era prey. University of Maryland paleontologist Thomas Hotz, Jr. described the beast as “banana-tooth[ed]”—and he was talking about size, not sharpness. The animal’s name alone—Lythronax argestes—tells you the rest of what you need to know. The Lythronax part means “king of gore.”

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