World’s biggest web-spinning spider

Halloween is approaching, and what better story to get us in the spooky mood that the discovery of the world's largest web-spinning spider.

The record breaker, named Nephila komaci, is a type of golden orb weaver spider from Africa and Madagascar. The female have bodies up to around 4cm long (1.5 inches) and their legs reach to 12cm: so she would stretch out across the palm of your hand. The males are much tinier, about 5 times smaller than the giant females.

Tarantulas still hold the title of king of the spiders. The Goliath bird eating tarantula from South America has a leg span of 30cm and inch-long fangs! But they don't make webs.

This giant web-spinner is the discovery of Matjaz Kuntner from the Slovenian Academy of Sciences and Arts and Jonathan Coddington from the Smithsonian National Museum of Natural History in Washington DC, publishing in the online journal PLoS One.

And for a long while they thought this spider that was first found in 1978 must be extinct, or perhaps a hybrid of two other species, because only that single specimen was known. Together these two researchers went on expeditions to South Africa but they failed to find a living specimen of this giant spider. And even searching through 2500 more specimens from 37 museums, still another one didn't show up.

Then eventually, another specimen turned up from Madagascar, and three more were found in South Africa, confirming that this is indeed a new species.

That adds another name to the list of around 41,000 spider species that are currently known to science (every year another 400 or 500 are added).

While obviously being an important discovery for spider biodiversity, these spiders also shed light on how and why some female animals evolve to be much bigger than their male partners. In their paper, the spider sleuths build a family tree of the known species of Nephila spiders, showing that there is a branch of African spiders in which the females evolved to be bigger and bigger over time.

The discoverers of this fantastic new species are urging others to go and try and find more of these spiders, because they are obviously extremely rare and they want to know more about them. The only place they are definitely known to live is in the sand forests of Tembe Elephant Park in KwaZulu-Natal in South Africa.

A rare wonder indeed and a treat for Halloween...