Illacme tobini , a new millipede discovered in Sequoia National Park. That little white bar is a millimeter long. | Photo: Paul Marek , Virginia Tech

When a new species turns up in the tropics it's something of a humdrum affair. A single hectare of Yasuni National Park in Ecuador contains more kinds of trees than in all of North America, and each of those trees comes teeming with life. You can't sneeze without hitting something as yet unknown to science. The trick, of course, is to have the expertise to realize when you're staring at something new.

What's considerably more atypical is to discover a new species right here in California, but that's what a group of researchers based in Virginia and Texas have just done.

Meet Illacme tobini. This millipede has a whopping 414 legs (207 pairs), 200 orifices that may be poison glands, and an impressive four penises, which are modified legs more accurately called gonopods. All of that gets packed into a creature less than an inch and a half long. The description of the new species was published last month in the journal ZooKeys.

Illacme tobini lives in the quiet darkness of Sequoia National Park's Lange Cave, which explains its ghostly white appearance. When you live in eternal night, coloration is a waste of time and energy.

There are 275 known caves in Sequoia and Kings Canyon National Parks. (The two parks are managed as a single unit by the National Park Service.) That makes the park home to the second largest cave system in the US, following Mammoth Cave National Park in Kentucky. While most of the caves are off-limits to visitors thanks to the Federal Cave Protection Act of 1988, they do occasionally host visiting scientists. From 2002 to 2004 and again from 2006 to 2009, biologists conducted a survey of the caves' invertebrate fauna. In all, they found nearly thirty new taxa, including this millipede.

It was on October 9, 2006, when researcher Jean K. Krejca, from the Texas-based Zara Environmental LLC, an environmental consulting firm, scooped up the one individual Illacme tobini now known to science. Indeed, when expeditions were mounted in 2009 to find more individuals, not a single one could be found. Which doesn't mean they're not there, of course, only that we don't know anything about them – including what kinds of habitats they prefer.

What we do know, thanks to the genetic information extracted from parts of the critter that aren't being preserved, is that its closest known relative is I. plenipes, which is found with its even more impressive 750 legs some 150 miles to the west in San Benito County, California. After that, the pair's next closest relatives live in South Africa.

"In many of the caves, there's not a lot of differentiation of temperature throughout the year, so the climate is rather stable," says Annie Esperanza, Branch Chief of Physical Sciences for Sequoia and Kings Canyon National Parks. "As we learn more about these invertebrates, if climate should change, they may be good indicators."

While these critters and their other invertebrate neighbors may indeed prove somehow functionally useful to us as climate change sentinels, their importance may remain fairly esoteric for most folks.

"Not a lot of people wander about in caves, just like not a lot of people go into the depths of the ocean," says Esperanza. "In an era where we are data rich, that we still find something new should be a wake up call to think about all the other biodiversity out there that we don't even know about,"she adds.

Indeed, there will always be new discoveries waiting in even the most intensively studied landscapes on the planet. There is excitement in exploration, and we humans are nothing if not explorers.