Page last updated at 02:21 GMT, Wednesday, 21 October 2009 03:21 UK

'Giant' orb web spider discovered

Orb-weaviing spider Nephila inaurata
Orb-weaving spiders can spin webs of up to 1m (3ft 3in) in diameter

A new and rare species of "giant" orb web spider has been discovered in Africa and Madagascar.

In the journal Plos One, researchers describe Nephila komaci as the largest web spinning spider known to science.

Only the females of this groups of species are giants, with a leg span of up to 12cm (4.7in); the male spiders are tiny by comparison.

Scientists say the female spiders are capable of spinning webs that reach up to 1m (3ft 3in) in diameter.

Orb-weaving spiders are a widespread group which take their name from the round webs they typically spin.

Diagram of orb-weaving spider body Nephila komaci
The few preserved female specimens had bodies almost 4cm (1.5in) long

The new spider was identified by Matjaz Kuntner, a biologist from the Slovenian Academy of Sciences and Arts, and his colleague Jonathan Coddington, from the Smithsonian Institution's National Museum of Natural History in Washington DC.

Dr Kuntner told BBC News that the discovery was "very unusual" because Nephila spiders were so well-studied and so large.

But this species is so elusive that even Dr Kuntner has not seen one live. He was able to identify the species from a specimen he first examined in 2000.

The giant female was in a collection belonging to the Plant Protection Research Institute in Pretoria, South Africa.

"It did not match any described species," said Dr Kuntner.

In his search through more than 2,500 samples from 37 museums, no further specimens turned up and he assumed the spider must be extinct.

But when a colleague in South Africa found three more of the spiders, it became apparent that they belonged to this same new species.

Orb-weaviing spiders <i>Nephila komaci</i>
Male Nephila spiders look tiny in comparison to "giant" females

The discovery will enable scientists to study the evolution of the dramatic size difference between male and female Nephila spiders.

Dr Kuntner explained that the widely accepted theory was that evolutionary pressure was causing female "gigantism", with the females increasing in size in order to produce larger numbers of offspring.

He and his colleague, Jonathan Coddington, from the Smithsonian Institution's National Museum of Natural History in Washington DC, fear the rare spider might be endangered.

"Its range is restricted and all known localities lie within two endangered biodiversity hotspots: Maputaland and Madagascar," said Dr Coddington.

Dr Kuntner named the species in honour of his best friend and fellow scientist Andrej Komac, who recently died in an accident.

Spider size comparison graphic



Print Sponsor


SEE ALSO
'Veggie' spider shuns meat diet
12 Oct 09 |  Science & Environment
Ancient spiders yield 3D secrets
05 Aug 09 |  Technology
Welcome to the Spiderlab
09 Jun 09 |  Science & Environment

RELATED INTERNET LINKS
The BBC is not responsible for the content of external internet sites


FEATURES, VIEWS, ANALYSIS
Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit

BBC navigation

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.

Americas Africa Europe Middle East South Asia Asia Pacific