Scientists Discover Spider Fossil which is oldest On Record. (20 April 2011)

[güttsfükk]

The legs would have spanned up to 15cm, front to back (scale-bar: 5mm)

Fossilised spider 'biggest on record'

Scientists have described a Chinese spider they say is the biggest fossilised arachnid yet found.

The female, which lived about 165 million years ago, belongs to a collection of spiders well known today - the golden orb weavers.

These creatures make webs from a very tough and distinctively golden silk.

The researchers tell the journal Biology Letters that Nephila jurassica, as they have called their specimen, would have had a leg span of some 15cm.

"She is the largest known fossil spider," said Professor Paul Selden from the University of Kansas, US.

"Her body is not the biggest, but if you add in her long legs then she's the largest," he told BBC News.

Today's Nephila species are found around the globe in tropical and sub-tropical regions.

Until this new fossil turned up in Inner Mongolia, the most ancient example from this grouping, or genus, was about 35 million years old.

So, this discovery pushes the existence of the Nephila back to the Jurassic Period, making them the longest ranging spider genus known.

No-one can say for sure how this particular arachnid met her end, but she may have succumbed to a natural catastrophe.

The spider was encased in volcanic ash at the bottom of what would have been a lake. Perhaps the ash fall from an eruption pulled her from her web and smothered her. Whatever the circumstances of the spider's end, the preservation of detail today is exquisite.

"You see not just the hairs on the legs but little things like the trichobothria which are very, very fine. They're used to detect air vibrations. There's a very distinct group of them and they're a very distinct size which is typical of this genus, Nephila," Professor Selden explained.

Nephila females today weave some of the largest orb webs known, up to 1.5m in diameter. The great prowess of the females stands in stark contrast to the rather diminutive males of the genus. Their small form makes the females look like giants.

This disparity in size is an example of what biologists refer to as extreme sexual dimorphism.

Professor Selden and his colleagues are keen to find out whether this characteristic holds true for the ancient Nephila, too.

"The previous oldest Nephilid is a male from the Cretaceous Period found in Spain. That male is normal sized, whereas in the present day the females are giants," the Gulf-Hedberg distinguished professor of invertebrate paleontology at Kansas said.

"So, it looks like we may have this dimorphism going back this great length of time. We'd like to find a male in the deposit to confirm this. All the evidence would suggest the male would be normal size, but we haven't yet located one."

Source : http://www.bbc.co.uk/news/science-environment-13134505

A modern female golden orb weaver with a small male in close attendance

[mengala]

Back then because of the high oxygen levels, bugs and arachneids grew to gigantic proportions.

[commondenom]

well how big is it??

[güttsfükk]

A closeup of Nephila jurassica’s right leg, showing tiny fossilized hairs.

[Faline]

Originally Posted by mengala

Back then because of the high oxygen levels, bugs and arachneids grew to gigantic proportions.

Glad i wasn't around then

[güttsfükk]

i've changed the title as it's misguiding, the actual fossil is apparently only 2 inches long but it's the oldest spider fossil or something like that apparently.

and it's the biggest fossil of a spider apparently which is why the original title was written as it was. but i find it misguiding

[candymosh]

the close up of the leg is amazing.....but yeck, spider!!

[rol]

The largest ever fossil of a prehistoric spider, 165 million years old with a six inch leg span, has been discovered.
Its fossilised features have been so perfectly preserved that experts have identified it down to the exact species and were even able to tell it was an adult female.

The Golden Orb Weaver has been named Nephila jurassica. It lived in the forests of northern China when the climate was much warmer and more tropical than today.

Its discovery in Inner Mongolia means Golden Orb Weavers, or 'nephilids' – giant spiders that can grow bigger than a human hand and which still thrive today – are the longest ranging spider genus known to man in terms of age.

Prof Paul Selden, a paleontologist from Kansas University, said the females are the largest web-weaving spiders alive today with a body length of up to two inches and a leg span of six inches. Males are relatively diminutive in comparison.

They are "common and spectacular" inhabitants of tropical and subtropical regions with females weaving distinctive five foot wide webs of yellow silk that glisten like gold in sunlight.
Prof Selden, who reports his discovery in the Royal Society journal Biology Letters said the find means Golden Orb Weavers must have an unusually ancient lineage, an extremely long range for any animal genus.

The find also suggests the climate was "warm and humid at this time".

The legs would have spanned up to 15cm, front to back.

[deanmine]

I would Still Step on that fucker!!