The images of a nearly transparent worm with spots one of our readers sent presented an interesting challenge. Two of these specimens were found in this reader’s shower, and he was concerned they had come from him before going down the drain. He was able to take close up photographs with a high-definition camera; even then certain differentiating characteristics weren’t immediately clear.
We began by addressing the concern that this might be a parasitic worm of some sort. One type of parasitic worm, Ascaris worms, typically present as more white than transparent, without such pronounced ridges or segments. From the photo, it seemed as though the worm had tapered ends. We investigated as though it was an annelid (oligichaetes), or segmented earthworm. A pot worm is a segmented worms that never turn pink and are common in worm bins. These worms can be up to an inch or so long and don’t turn pink. Potworms are plant decomposers and largely harmless to humans.
What was distinctive about this worm was the spots down either side. This characteristic is not common in pot worms, although they can appear to have a stripe if their alimentary canal (or gut) is ‘full.’ It’s likely that this is a type of snake millipede, like the Cylindriulus punctatus, or blunt-tailed snake millipede. While the name is intimidating, it’s most likely that a bad smell is the worst of it from this specimen, but that might not have been noticed in the shower. The spots along its side are known as ozadenes, and are reddish or brownish glands that emit a foul smell when the millipede encounters a predator. Most millipedes also curl when threatened, and the reader didn’t mention any curling behavior.
It wasn’t clear from the photo that the worm had any pincers or jaws, however the Cylindriulus punctatus has a face-mask marking and a blunted (or clubbed) tail end that may be evident in the photos. If we could confirm that this near-transparent body has hundreds of little legs, we’d be able to provide a definitive identification.
Summary: The worm found in our reader’s shower is likely a spotted snake millipede, mostly harmless but able to secrete a foul smell if it feels threatened. It is unlikely the millipede fell from his body, but may have ridden in on clothes or shoes if he had been outdoors.