There are lots of ways to describe a type of millipede named Illacme plenipes. Creepy comes to mind. Repulsive. Gross. Stuff of nightmares. But by far the most apt description for this slithering arthropod is leggy. In fact, with up to 750 legs, Illacme plenipes is the planet’s leggiest creature. It was first described in 1928 and not spotted again until 2005. On Tuesday the journal ZooKeys published a “redescription,” or the first comprehensive analysis of a millipede whose only known range is a small region in Central California.
Images showing Ilacme plenipes, the leggiest creature on earth, are courtesy of Paul Marek
Naturally, the scientific media are running with the story, and having a bit of fun in doing so.
Writes Tim Barribeau of the website i09: “Look, I’m all for biodiversity, but 750 legs? That’s too damned many.”
States Becky Crew of Scientific American: “*Insert Angelina Oscars Leg joke here*, but the leggiest animal in the world is actually the millipede Illacme plenipes.”
All millipedes all have lots of legs, but Illacme plenipes, which means “in highest fulfillment of feet,” has more than the other 9,999 species. Females have more than the males and the Illacme plenipes featured in the accompanying video has 662 legs.
This prompted Outi Harvey, in the comment section of the i09 article, to state: “I pity the guy who has to count all those legs.”
But in seriousness, this is one remarkable millipede. Because it lives in the dark, it has no eyes, instead relying on huge antennae with which to find its way in a region known for its dense fog and oak forests. Presumably, the millipede requires so vast a supply of legs to maneuver through its subterranean realm of soft-packed soil. It can secrete silk, which helps it cling to the bottoms of sandstone boulders. Its fused mouth has evolved to help the arthropod pierce and suck fungi, and consume plants.
The first description of Illacme plenipes, in 1928, was by O.F. Cook and H.F. Loomis. But their report lacked photographic evidence or even an illustration, and over the years the species was presumed to have become extinct.
But in 2005, Paul Marek, from the University of Arizona, set out with his brother and discovered a live specimen under a moss-covered boulder in San Benito County. Their discovery was published in the journal Nature in 2006.
Marek told Scientific American: “To find this species in particular, one believed extinct over the past 80 years and this relict animal with 750 legs, was wonderful. To tell you the truth, and this is the experience every time I find a species I’ve never seen before, it was an exhilarating experience.”
Marek and his team found three more Illacme plenipes millipedes in December 2005, January 2006, and December 2007, all under sandstone boulders, and their findings are described in the ZooKeys report.
The report’s introduction begins with a mention of the world-record setting female millipede, possessing 750 legs on 192 body segments.
That’s 375 pairs of legs or, as Barribeau describes, too damned many.