Every year scientists around the world discover about 18 thousand species that are entirely new to science: animals, plants, fungi, protists, bacteria, every shape that life can take on this planet.

It's actually not that much when you consider that there could be as many as 100 million different species out there, but the number of discoveries we make every year is less important than what they tell us about the world when we look at them all together. Each new mite, flower, dog, fish, or finch comes to our attention by way of many other little discoveries that led to it finally being added to the official attendance list of planet earth. After all, every new organism has to not only be found, it has to be studied, compared, identified, and organized. That's taxonomy: the science of classifying living things and exploring the evolutionary relationships between them.

And to celebrate the latest achievements in this field as well as the birthday of the man who basically invented it, Swedish scientist Carl Linnaeus, every May the International Institute for Species Exploration weighs in on the most impressive discoveries of the previous year, the top ten new species of 2013. Who made the list this year? Well, it includes a glow-in-the-dark cockroach, a monkey with blue testicles, and the smallest vertebrate on Earth. Hopefully, that got your attention.

Yes, a monkey with blue testicles. We actually told you about the first species on the list last fall. It makes this year's top ten because it's only the second monkey species to be discovered in Africa in nearly 30 years, and, unsurprisingly, its species is in danger. Named C. lomamiensis, it was found by U.S. researchers in the evergreen forests of the Democratic Republic of Congo, which remain largely unexplored by scientists because of their remoteness and of the country's political instability. Despite its isolation though, the monkey, known to its friends as the Lesula monkey, is vulnerable and is hunted for meat. And the coloration I mentioned makes the males, at least, easy to spot. Their behinds, testicles, and everything in between are bright, light blue.

Not to be outdone, another new species can make itself seen in a different light. Literally. L. luckae is a newly identified species of giant lightning roach: a cockroach that glows under fluorescent light. Found in remote areas in South America, the lightning roach owes its bioluminescence to fluorescent bacteria that live in its shell, and not coincidentally the pattern it displays when it glows matches that of another poisonous beetle that emits light at the same wavelengths. This makes the lightning roach the first known species to use bioluminescence as a kind of defensive mimicry. But to me, it's just the first known species that looks a really lot like the Jawas on Tatooine. Am I right?

This list also includes another canny mimic, a snail-eating snake called Sibon noalamina, and no, I don't know how to pronounce these things. Found in the mountains of Western Panama, it lives on a diet of snails, slugs, worms, and amphibian eggs and bears a striking resemblance to venomous coral snakes. But like many organisms on the list, its habitat is threatened, in this case by mining. Biologists are so concerned about the impact of mining in the region that they gave the snake a name that means, in Spanish, "no to the mine."

Some species on the list haven't been identified until now not because they look like other species but because they've simply been overlooked. A new type of evergreen discovered along the coast of Madagascar, the pink-flowered E. petrikensis, turns out to be an important member of an ecosystem known as the littoral forest. That sounds like "literal." It is a literal forest, but it is also a littoral forest, which is with an "o," and that means that it's on the shore of a lake or the ocean, a habitat that happens to be fast disappearing in Madagascar.

Other species have been overlooked simply because of their size. The new-found Lilliputian Violet stands only 1 centimeter tall and is found on a single plateau in the Peruvian Andes. The world's smallest vertebrate was discovered last year in Papua New Guinea, P. Amanuensis, a frog that measures only 7 millimeters.

And while we're on the superlatives, the deepest we went to find one of this year's species was 34 hundred meters below the northern Pacific, where the lyre sponge lives. Noted for its large, harp-like shape and weird balls on the end of its branches, the lyre sponge is actually carnivorous, surviving on small crustaceans that it captures with hooks on its surface.

For one of this years top ten though, it is way to late to talk about survival. A scorpion fly called J. ginkgofolia lived 165 million years ago in China, making its living by hanging out under leaves to catch its dinner. Discovered only recently in a fossil, it too had probably been seen before but not noticed. Its wings so closely resembled the leaves of the ginkgo tree that it lived in many specimens had been mistaken for plant fossils.

Humans and fungi go back together a long way too, but this next species poses a threat to one of humanity's greatest creations. In the mid 2000s, mysterious black stains began to appear on the famous 17 thousand year old cave paintings in Lascaux, France. The culprit was identified last year, a species of fungus named for the famous cave where it's running amok, O. lascauxensis. It only started to flourish after workers treated the cave with another fungus, which O. lascauxensis seems totally unaffected by.

Finally, we have the internet to thank for the last species on the list. A few years ago, a tourist posted a picture he took on his Flickr page of a lacewing insect he found in a park near Kuala Lumpur. As it happens, a curious scientist in California came upon the photo and had never seen such distinctive wing markings before. After many, many emails and much worldwide collaboration a team came together around the photo and realized it was a new species, S. Jade.

You know if I had more time I'd share all 18 thousand newly discovered species with you, but ten will have to do for now. If you have a favorite discovery of 2012, or maybe a favorite way of celebrating Linnaeus's birthday, you can let us know on Facebook or Twitter, or in the comments below. And if you want to continue getting smarter with us here at SciShow, you can go to youtube.com/scishow and subscribe.