Experts unearth 27 new species in Sierra Nevada

Some of the species haven't been around too long, evolutionwise.
San Francisco Chronicle
Spelunking biologists have demonstrated that there are plenty of new things lurking where the sun doesn't shine -- in the caverns of the Sierra Nevada.
The scientists have discovered 27 new species of arachnids and other invertebrates -- including pill bugs, spiders and pseudo-scorpions -- in 30 caves at Sequoia and Kings Canyon national parks. Their findings were released this week.
"It's remarkable, really," said Jean Krejca, an associate with a Texas environmental consulting firm and the principal investigator in the expedition. "I think perhaps the most compelling thing about it is that it gives us the opportunity to ask and answer many evolutionary questions."
The creatures are unique not only because they are found only in caves. Some are found only in a single cave -- or even in a specific chamber of a particular cave.
Krejca and the other scientists found the critters during a biological inventory of the parks that was conducted for the National Park Service between 2002 and 2005.
By surface standards, the creatures are exotic. One, a type of daddy longlegs, has oversize mandibles, perhaps enabling it to eat super-size prey.
"We saw it eating dobsonflies, which are quite large," Krejca said.
Translucent qualities
Many others were translucent. Pigmentation isn't necessarily an adjunct to survival beneath the ground, said Krejca, and most subterranean animals do without it.
"Sometimes there is a genetic link between giving up pigment and gaining enhanced sensory abilities, which would help in securing food," she said. "Or the energy used for producing pigment could instead be used to produce greater numbers of offspring."
It is extremely rare to find new vertebrates -- mammals, birds, reptiles and amphibians -- on the Earth's surface, which has been thoroughly explored and largely surveyed.
But the planet's vast subterranean complexes are still terra incognita for the most part, and scientists discover new species -- particularly invertebrates -- in them with some regularity.
Still, said Krejca, finding almost 30 new species in a single study is anomalous. Krejca said researchers typically find surface variants of new cave species and compare them.
"It's like separating two twins at birth and seeing the ways they diverge," she said.
Not around long
One thing seems certain, said Krejca: The newly discovered species are new not only because they haven't previously been described in the scientific literature but because they haven't been around very long, in evolutionary terms.
"Ten thousand years ago, the area where they live was covered by glaciers," she said, "and it's highly unlikely they could've survived extended glaciation."
Cave species adapt to subterranean environments to different degrees, said Krejca. Many of the species recently discovered in the Sierra are troglobytes -- the most highly cave-adapted, Krejca said.
"Troglobytes are so specifically geared to caves that they can't survive on the surface," she said, "so they can't leave one cave and walk to another. They have to use underground pathways."
And for many cavern-dwellers, such pathways may not exist -- meaning that a critter that evolves in a specific cave stays there.
"So you can end up with lots of endemics in a small area," Krejca said. "That's what appears to have happened in Sequoia and King's Canyon."
An endemic species is an animal and plant that is found in a single locale and nowhere else.
So far, none of the new species has been named. Nor will that honor go to the researchers who discovered them, Krejca said.
"We've submitted the information to taxonomists, who will write up the actual species descriptions," she said. "They're doing most of the hard work, so they get to name them."