A new species of millipede, discovered in a cave in California, joins the rarely-seen family of Illacme, known for having more legs than any other animal on the planet. The new creature, dubbed Illacme tobini, has been studied from a single male specimen and boasts a strange list of body parts, including 414 legs (four of which function as its penises), 200 poison glands that spray an unknown chemical, mysterious mouthparts and a body covered in hairs that secrete silk.

Not much is known about the Illacme family of millipedes. Until the discovery of tobini, the sole species was the Illacme plenipes, first described in 1928 then not seen again in the wild for another 80 years. Of the 17 specimens in collections around the world, one holds the record for the leggiest animal on Earth, with a total of 750 legs. Most of the plenipes specimens were found near San Juan Bautista in California, and their rarity makes the new discovery particularly exciting for diplopodologists – scientists who specialize in the study of millipedes.

"I never would have expected that a second species of the leggiest animal on the planet would be discovered in a cave 150 miles (240 km) away (from the plenipes site)," says Paul Marek of Virginia Tech, one of the researchers who described the new species.

Just one Illacme tobini specimen was found in a cave during an expedition to Sequoia National Park in 2006, despite thorough searching in the cave and surrounding areas for more of them. It was preserved in ethanol, dissected and had samples of its DNA extracted, and study of its anatomy found it to be a close relative of the plenipes, but a distinct species.

With a tally of 414 legs, this one specimen sounds far short of the record-holding 750, but it is about average for the better known Illacme species. The tobini's four penises are actually four of its legs, repurposed for reproduction, and the body is covered with tiny hairs that appear to secrete a silk-like substance. Further adding to the mystery, pores in its mouth seem to give off an unknown secretion, and each of its segments is adorned with a pair of glands that spray poison, although just what it sprays also hasn't been identified.

Since only the one specimen has ever been found, the researchers can't be sure how widespread the Illacme tobini is, but it likely has a pretty limited range. They conclude that the area should be explored and surveyed in more detail to paint a better picture.

The research was published in the journal Zoo Keys.

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