Scientists have finally figured out what the Arthropleura’s head looks like, and I say it’s about time.

It’s always a satisfying feeling to learn of a problem you didn’t even know about and have it solved in the very same moment. According to the Associated Press, Arthropleura is the biggest bug that ever existed. Nine feet long, a hundred pounds. There was a picture. It looked like a centipede.

Right away I am squirming with a case of Acquired Crotchet Syndrome. That’s when something that wouldn’t ever have bothered you starts to stick in your craw because you know how much it bothers someone else. To wit: clearly Arthropleura is not a bug. Maybe most people refer to almost anything in the Arthropod phylum as a “bug,” but a number of people of my acquaintance would be stamping their feet and growling over their Cheerios about this reference, annoying their roommates, because they know True Bugs are in the Hemiptera order of insects, and this sucker clearly isn’t.

It’s not my crotchet, but I have strong empathy with fussbudgets. Fussbudgets will rail about people using “poisonous” and “venomous” interchangeably. Fussbudgets will lose their mind when they encounter someone who thinks kudos is the plural of kudo. It’s silly to get all worked up about these things, which are ultimately minor gaffes. (Although, ahem, there is no excuse for mixing up amphibians and reptiles.)

Anyway, the problem with this well-known fossil is that it is always missing a head, which goes a long way toward explaining why it’s extinct, I’d think. Apparently these fossils are of exoskeletons left behind when their inhabitants molt into the next-larger size, and they exit through the head and mess up the eventual fossil. The reason this is a problem for science, other than a sincere desire to get the drawing right, is that without the head they can’t figure out if the critter is related to centipedes or millipedes.

Perhaps many people would roll their eyes at the notion that this is something we need to clear up, but those same people will spend time and money to evict dandelions from their lawn or bags from under their eyes. Of course we need to know this. Paleontologists have been collecting these fossils for 150 years and wondering about the heads the whole time.

And now they’ve got a pretty good idea. There are much smaller versions of Arthropleura buried in the rock, probably two-inch juveniles, with heads on them, but their heads are too fragile to be successfully chipped out. Enter the CT scan, the marvelous invention that uses X-rays to reveal cancers, blood clots, and ancient arthropod heads.

Yes. The human being has evolved to the point of being able to accurately render the tiny head of a 300-million-year-old crawler, right down to the eye-stalks, curved antennae, and little mandibles, and determining the creature was most closely aligned with millipedes, but with a centipede-like head, except for the stalked eyes, which is not a known feature of either group, and suggests that—although terrestrial—the animal may have had an aquatic phase as a youngster.

This is something to celebrate. You’re not going to get a billionaire to show any interest unless he can ride a rocket to the fossil dig, but that’s his loss. We’re not going to learn anything more interesting than that today, and that’s a fact.

But it’s not a bug. Learn that too.