Aphonopelma johnnycashi
Researchers named this species of tarantula after singer-songwriter Johnny Cash Dr Brent Hendrixson and Dr Chris Hamilton

The biggest ever taxonomic investigation on tarantulas found 14 new species in the US, including one which was named after legendary singer-songwriter Johnny Cash. A study analysed more than 3,000 specimens of tarantula across the US, and the research found there are 29 species across the country – nearly half of which had never been recorded before.

American tarantula species appear very similar in how they look, and past reports from the public have often been very vague or tend to overlap with other species. Researchers set out to officially describe all of these species themselves. They published their results in the journal ZooKeys.

"We often hear about how new species are being discovered from remote corners of the Earth," said Chris Hamilton, lead author of the investigation. "But what is remarkable is that these spiders are in our own backyard. It is astonishing how little we know about our planet's biodiversity, even for charismatic groups such as tarantulas."

The biggest and smallest of the 29 species of tarantula found in the US Dr Brent Hendrixson and Dr Chris Hamilton

One of the species discovered was named after Johnny Cash – Aphonopelma johnnycashi. It was found near Folsom Prison in California, the penitentiary that inspired Cash's song Folsom Prison Blues.

To identify the new species, the researchers tried to find differences in the specimens' characteristics, as their appearance can be very similar. The spiders were analysed all across the country, from harsh arid environments, to mountain tops in Arizona.

It was decided that of all specimens, they should be classified into 29 species, including 14 brand new ones.

"Two of the new species are confined to single mountain ranges in south-eastern Arizona, one of the US' biodiversity hotspots," said Brent Hendrixson, researcher on the study. "These fragile habitats are threatened by increased urbanisation, recreation, and climate change."

The scientists say that some of the species are already extremely rare due to human influence and an increasing loss of habitat.

There are around 40,000 species of spider across the world – everywhere except Antarctica. Arachnophobia – a fear of spiders – is the third most common fear among humans.