The leggiest animal in the world, the millipede lllacme plenipes, was re-discovered several years ago in California by Paul Marek. Now, Marek and his colleagues provide further details of the surprisingly complex anatomy of this diminutive creature and its extreme rarity, limited to a handful of spots just south of San Francisco. More details about the species and its biology can be read in an article that was recently published in the open access journal ZooKeys.
Millipedes have the most legs of any animal group. From their ancestors with just one pair of legs per body segment, millipedes evolved two pairs (four total) through segmental fusion. This coalescence of segments happened deep in the evolutionary history of millipedes, more than 400 million years ago. Four legs provide more thrust on a per segment basis, which benefits millipedes to help them burrow underground--e.g., to escape predators or access new resources. Those individuals with a coalescence of segments and hence a better burrowing ability, were able to persist in this early primordial ecosystem.
The most noticeable thing about millipedes are their number of legs, which lined up along their bodysides step in synchronous "metachronal waves". The acme of legginess in millipedes, and all animals for that matter, is the Californian species Illacme plenipes (literally meaning "in highest fulfillment of feet"). The females have up to an astounding 750 legs, outclassing the males who only have a maximum leg count of 562. The proliferation of legs may be an adaptation for its lifestyle spent burrowing underground or (based on the presence of features like legs with bifurcate claws and other traits known to be associated with rock-climbing in millipedes) enable it to cling tightly to the sandstone boulders found exclusively associated with the species in its habitat
Not only is this species the leggiest animal known on the planet, it also has surprising anatomical features: body hairs that produce silk, a jagged and scaly translucent exoskeleton, and comparatively massive (given its diminutive size) antennae that are used to feel its way through the dark because it lacks eyes. Its mouth, unlike other millipedes that chew with developed grinding mouthparts, is rudimentary and fused into structures that are probably used for piercing and sucking plant or fungal tissues.
This rare and ancient-looking creature's home is California, on the outskirts of Silicon Valley. The species is exceedingly scarce and limited to just a single tiny area near San Juan Bautista, just east of the San Andreas Fault. Based on the known environmental conditions where it lives, the species' probable distribution elsewhere in California was inferred. Yet still restricted to a small geographical range, the analysis indicated other areas of suitability limited to the terrestrial areas on the edge of Monterey Bay eastward to San Juan Bautista and throughout the Salinas Valley. What's unique about this area, and seems to be correlated with the model's area of highest suitability, is the thick layer of fog that accumulates in the area--like soup in a deep bowl. The fog and the species' unique set of features in its habitat (oak forests, sandstone boulders, and fine sandy soil) make this area a special place and certainly deserving of attention as the home of this rare and superlative beast.
Marek PE, Shear WA, Bond JE (2012) A redescription of the leggiest animal, the millipede Illacme plenipes, with notes on its natural history and biogeography (Diplopoda, Siphonophorida, Siphonorhinidae). ZooKeys 241: 77. doi: 10.3897/zookeys.241.3831
Pensoft Publishers: http://www.pensoft.net
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Free-living songbirds show increased stress hormone levels when nesting under white street lights. But different light spectra may have different physiological effects as this study finds, suggesting that using street lights with specific colour spectra may mitigate effects of light pollution on wildlife
Scientists identify the condition aphantasia, in which people cannot create images in their head
The dust in our homes contains an average of 9,000 different types of fungi and bacteria, a study suggests.
A mosquito can bear up to 23 times its total body weight on each leg, which is crucial for landing on water – the insect's secret is way it stands
Tropical species with smaller geographical ranges are more likely to die out in a warming climate than those that can adapt by ‘invading’ new regions
Most people think of bacteria as germs, signs of filth, or unwanted bringers of disease. Slowly, that view …
The gloomy octopuses crowded at Jervis Bay, Australia, appear to spit and throw debris such as shell at each other in what could be an intentional use of weapons
Therapies based on hormones that make us more trusting enhance our natural placebo effect – a finding that could alter the way clinical trials are conducted
The blind, hairless babies born recently at Washington D.C.'s National Zoo are completely dependent on their mothers—who can sometimes accidentally crush them.
The poop-hoarding insects have an amazingly advanced internal GPS that allows them to navigate by day or night.