Image copyright Chris A Hamilton Image caption Adult males of the new species Aphonopelma johnnycashi are almost entirely black

A new species of black tarantula that lives near Folsom Prison, California, has been named after Johnny Cash.

The famously black-clad country singer wrote a song about the prison, and also played a historic series of concerts for inmates there in the 1960s.

Aphonopelma johnnycashi is among 14 new tarantula species from the southern US which have been described by biologists in the journal ZooKeys.

Their study completely rewrites the family tree of the Aphonopelma genus.

One of dozens of tarantula genera, this group was previously considered to include more than 50 separate species.

As part of his PhD research at Auburn University in Alabama, Chris Hamilton carefully whittled that down to 29. He eliminated a lot of double-counting, but also defined 14 species that were entirely new to science.

I have a Johnny Cash tattoo so I was very happy that it worked out that way Chris Hamilton, Biologist, Florida Museum of Natural History

"We really tried to clean the taxonomy up," said Dr Hamilton, now a postdoctoral researcher at the Florida Museum of Natural History.

"The only way we could do that was by looking at over 3,000 specimens, both from the wild and from natural history collections.

"A lot of previous names got eliminated. But there were 14 that were genuinely unique and new."

It is a telling example of the biodiversity to be found - sometimes literally - in our own backyards, he added.

Image copyright Brent Hendrixson/Chris A Hamilton Image caption Tarantulas in the Aphonopelma genus range from the 15cm A. anax (left) to tiny A. paloma (right)

"A lot of people think of new species as coming from areas of the Earth that not many humans have been to before... but that's really frankly not the case."

In particular, existing collections are a precious resource for scientists who want to study life's family tree.

"The majority of species, described or undescribed, have probably already been collected," Dr Hamilton told BBC News. "They're sitting on shelves waiting to be discovered."

'Perfect name'

Aphonopelma johnnycashi, however, was found roaming the wilds of California.

"It's found along the foothills of the western Sierra Nevada mountains, and one of the places that's there is Folsom Prison," Dr Hamilton explained - and it wasn't a giant imaginative leap from there to the species' new moniker.

"It's a perfect name. It fits the spider - it's found around Folsom and the males are predominantly all black, so it fits his image.

"I have a Johnny Cash tattoo so I was very happy that it worked out that way."

Image copyright Getty Images Image caption Johnny Cash famously performed inside Folsom Prison in the 1960s

Dr Hamilton thinks that one reason the species had not been previously recognised is its similarity to other species of tarantula, such as Aphonopelma iodius which is common in the Mojave desert further south.

"They look fairly similar, particularly the females. The males, because they're more black, they're a little bit different.

"But if you were just looking at specimens that had been collected, and they were in a jar on a shelf, they would look pretty similar."

So wild collecting of johnnycashii males, before their dark hairs could fade in jars of preservative, was key.

"Then once we looked at the genomics and looked at some of the ecological constraints, we could see this species was pretty unique and independent from the others that it's closely related to," Dr Hamilton said.

Follow Jonathan on Twitter