If you happen to live in the American Southwest and are afraid of spiders, then you might want to keep an eye out. Researchers have just described 14 new species of tarantula, nearly doubling the total number of the large arachnids known from the region. One of them has been named after music legend Johnny Cash, as it was discovered near Folsom Prison, made famous by Cash’s song “Folsom Prison Blues.”

“We often hear about how new species are being discovered from remote corners of the Earth, but what is remarkable is that these spiders are in our own backyard,” says Dr. Chris Hamilton, lead author of the study published in the journal ZooKeys, in a statement. “With the Earth in the midst of a sixth mass extinction, it is astonishing how little we know about our planet's biodiversity, even for charismatic groups such as tarantulas.”

The naming of so many new species is the result of over a decade of trawling through the baking hot deserts and chilly mountains of the American Southwest for the arachnids, and collecting nearly 3,000 specimens. The team decided to undertake the immense inventory of species living in the region because the historic list of arachnids described for the entire U.S. is messy and outdated, with many spiders listed twice or poorly defined.   

^{The largest (Aphonopelma anax) and the smallest (Aphonopelma paloma) tarantula species found in the United States. Dr. Brent Hendrixson (A. anax)/Dr. Chris A. Hamilton (A. paloma)}

While most think of tarantulas as being the massive spiders that nightmares are made of, they range in size considerably. It’s true that some do reach a fairly impressive size of around 15 centimeters (6 inches), but others are a more diminutive 5 centimeters (2 inches) long. The arachnids are found in a total of 12 states across the southern third of the U.S., with 50 species from North America having been described.   

Many of the tarantulas living in the U.S. are similar in appearance, making them hard to identify. Because of this, the researchers had to use a mix of characteristics, from their appearance to their behavior and genetics, to tease apart which are separate species. Using this approach, the researchers were able to identify 29 species, up from the 15 that were previously known from the Southwest.

While most of the species described have quite wide ranges, they found that a few of them were heavily restricted, and could be in need of protection. “Two of the new species are confined to single mountain ranges in southeastern Arizona, one of the United States' biodiversity hotspots,” explains Brent Hendrixson, co-author of the study. “These fragile habitats are threatened by increased urbanization, recreation, and climate change,” in addition to the potential threat from the pet trade.