One of the animal kingdom’s more non-exclusive semantic clubs is that of the worms. Are you “any of a number of creeping or burrowing invertebrate animals with long, slender, soft bodies and no limbs,” as the New Oxford American Dictionary defines you? Well come on in—we have a seat just for you. From the ferocious (seriously) predatory marine bobbit worm to the horsehair worm, which invades crickets’ bodies and mind-controls them, it’s a club that’s as incredibly neat as it is diverse.
Hell, even if you have kinda-limbs we’ll consider letting you in. We’re looking at you, the more than 100 species of velvet worms, with your adorably stubby legs, face cannons that fire immobilizing slime, and nasty jaws that bore right through arthropod armor. You’re so ancient and unique and bizarre, so far removed from something like the average earthworm, that you get your very own phylum. But welcome to the club all the same.
The velvet worm may be velvety and squishy and tiny—between 0.5 and 6 inches long—but this critter is a ruthless hunter, not to mention quite the survivor. Velvet worms have been stalking Earth almost as long as land animals have existed. “They evolved during the Cambrian, approximately 540 million years ago, from a marine group called the lobopodians,” said biologist Ivo de Sena Oliveira of Germany’s University of Leipzig. “And despite their fragile aspect, velvet worms were able to overcome several geological, climatic, and vegetation changes until today.”