Mostly due to their large size, tarantulas occupy a unique place in popular culture. From Tarzan to Indiana Jones, film-makers have long understood their power to induce arachnophobia in the masses. In São Paulo, researchers Bertani, Nagahama and Fukushima have discovered a beautiful new species of tarantula from Bahia and Minas Gerais, Brazil, that deserves a starring role. Male and juvenile individuals of Pterinopelma sazimai are cryptically coloured in browns and greys, but the female sports a coat of iridescent blue hair that is truly spectacular.

Specimens were collected from a montane subtropical savanna eco-region of eastern Brazil known as the "campo rupestre". Perched atop rocky outcrops above 900 metres, the plants endemic to these tabletop mountains have been studied by botanists, who conclude that the higher rainfall and very different surrounding soil types make them ecological islands. As with all island situations, the occupied area is limited and therefore unique plants and animals are vulnerable. The limited distribution of Pterinopelma sazimai places it in a category deserving of conservation attention.

This is not the first blue tarantula. The cobalt blue tarantula, Haplopelma lividum, is an Asian species described in 1996 that is endemic to Myanmar and Thailand and has iridescent blue legs. There are about 900 species of tarantula in more than 100 genera distributed around the world in tropical and desert regions. They are predators that line burrows with silk or, in the case of some arboreal species, build silk "tube tents". The largest species can kill small mammals, lizards and birds.

Quentin Wheeler is director of the International Institute for Species Exploration, Arizona State University