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Rock Falls In Yosemite National Park Provide Homes For Curious Scorpion-Like Creature


The Yosemite Cave Pseudoscorpion can be found in caves created by rock falls in Yosemite National Park, so watch where you tread. NPS photos.

Just in time for Halloween -- a new bug to give you the creeps. This newly found arachnid apparently has been living in caves created by rock falls in Yosemite National Park for some time.

The tiny Yosemite Cave Pseudoscorpion (Parobisium yosemite), a variety of pseudoscorpoion, prefers the cool, dark spaces of these talus-slope caves, according to park officials.

A pseudoscorpion is a small arachnid that resembles a true scorpion but does not possess a stinger or a tail. The tiny arachnid was found deep in passageways, at the end of light zones, among granite sand, granite rocks, and leaf litter and debris. They survive at an average temperature of 51 degrees Fahrenheit. The Yosemite Cave Pseudoscorpion is believed to prey upon mites, flies, small spiders, beetles, ants, and millipedes.

The pseudoscorpions are about the length of a fingernail. They possess no posterior eyes and lack the typical tapetum, the layer of reflective tissue that is present on the back of the eye. The Yosemite Cave Pseudoscorpion also presents an atypical color, which is a tan/amber coloring, with reddish-brown legs. The main differences between the cave-adapted Yosemite Cave Pseudoscorpion and other pseudoscorpions are related to their loss of eyes and their elongated palp, the pincer like feature on the front two legs of scorpions and pseudoscorpions.

"We are thrilled about the new discovery of this fascinating species. Yosemite National Park is one of the great laboratories of the natural world and finds like this are incredibly exciting. We will continue to study the pseudoscorpion, as well as look for other new species of flora and fauna," said Niki Nicholas, chief of Resources Management and Science at Yosemite.

The pseudoscorpion is known as a troglobite, a small cave-dwelling animal that has adapted to a dark environment. Such species typically include spiders, insects, and fish. Most troglobites live permanently underground and cannot survive outside of their cave environment. Sixteen other species of pseudoscorpion exist, all from the northern hemisphere, including from the United States, China, Japan, and South Korea.

Ongoing research on the Yosemite Cave Pseudoscorpion is being conducted to further understand this new species. This discovery will further inspire Yosemite biologists to explore regions of the park not traditionally sampled for new fauna. Additionally, biologists in Yosemite have made it a top priority to continue further research into the talus cave ecosystem and biology to learn more about these relatively unexplored areas.

The Yosemite Conservancy, the primary fundraising organization for the park, contributed vital funding for the important fieldwork that lead to the discovery of this new species in Yosemite National Park.

The exact location of the caves in which the pseudoscorpions were found is being withheld to protect the tiny cave-dwellers.

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Looks a little like Yosemite Sam, don'tcha think? Small... claws reminiscent of his red mustache... I'm just sayin'...

For those that can't visualize the comparison...

We get the smaller cousins of these big guys in our house all the time. They are actually quite adorable, for insects, and very much smaller than these. Ours hunt for mites and bugs in the carpeting and come in on the dog's fur. When we find them, we scoop them up with a piece of paper, as they are quite delicate, and release them outside where there is more food for them than in our house.

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