Record-breaking millipede discovered on outskirts of Silicon Valley

Scientists from the University of Arizona have released a video of the leggiest animal on Earth, the  millipede Illacme plenipes, which has 750 legs.


Illacme plenipes, meaning literally ‘the pinnacle of plentiful feet,’ lives only on the outskirts of Silicon Valley.

Millipedes are the leggiest of all animal groups. More than 400 million years ago, their ancestors doubled their number of legs per body segment, evolving from just one pair of legs per segment to two (four in total). This extra bit of thrust allows the millipede to burrow underground in search of new food or to escape from predators.

This record-breaking millipede is only found under a particular type of large ‘arkose’ sandstone boulder in the northwestern foothills of the Gabilan Range and is extremely rare, with only 17 specimens known to exist in natural history collections. 

“This relict species is the only representative of its family in the Western Hemisphere. Its closest presumed relative, Nematozonium filum, lives in South Africa and this early relationship was established more than 200 million years ago when the continents coalesced in the landmass Pangaea,” said  lead author Dr Paul Marek.

“In contrast with its small size and unassuming outward appearance, the microanatomy of the species is strikingly complex,” write the paper’s authors in a study published in the open access journal ZooKeys.

The millipede has a jagged and scaly translucent exoskeleton, covered with body hairs that produce silk.  It also has no eyes, relying instead on a large pair of antennae to navigate its way through the dark. Another bizarre feature is its mouth; unlike other millipedes which chew on food by grinding their mouthparts, lllacme plenipes’s mouth is undeveloped and fused into structures that are probably used for piercing and sucking plant or fungal tissues.  

This slightly ferocious appearance is perhaps offset by the fact that at 0.4-1.2 inches (1-3 centimeters) long, the millipede’s features are only really apparent when viewed under a microscope.