Prehistoric spiders

[Wild-Woman]

Just out of interest. Are today's spiders descended from a common prehistoric spider and if so, were they any bigger than spiders today? Everything seemed to be bigger back then. I have seen them trapped in amber and they seem to be pretty well unchanged.
It'd be great if one was about a metre wide like the ancestor of today's dragonflies.

[ron1863]

I would love to see your face if there was one that size in your bathroom. Maybe the spiders were bigger back then but it would need an awful lot of pine resin to trap them

This might interest you though Jules:

http://www.wired.com/science/discove...lery_digimorph

[KeenTeen17]

The larger insects and arachnids of the Carboniferous era were able to grow to really large sizes due to the large amounts of oxygen and lack of land mammals as they hadn't evolved yet. Not sure about the ancestry though.

[Wild-Woman]

Originally Posted by ron1863

I would love to see your face if there was one that size in your bathroom. Maybe the spiders were bigger back then but it would need an awful lot of pine resin to trap them

This might interest you though Jules:

Scientists Virtually Dissect Prehistoric Spider Frozen in Amber

Thanks for that Ron. Innards too.Amazing.

Spider that big...you'd have to lassoo it and ride it out!

[Acutipuerilis]

The earliest true spiders appear to have been Carboniferous, and before them there were things like trigonotarbids (spider-like but with partly segmented abdomens). There used to be a famous giant Carboniferous spider called Megarachne, but this has turned out to be a partly-exposed sea-scorpion instead.

I don't actually know of any fossil spiders the size of our bird-eaters, although I'm sure they existed (something had to eat those pesky tyrannosaurs). Part of the problem is that they don't live in places with easy fossilization potential, and the larger the spider, the more appetizing for scavengers.

[Meta menardi]

There are a family of spiders called the Liphistidae still around in some parts of the world that show segmentation of the abdomen. This is very primitive and quite a step back from most of the spiders we know, and there are only about 40 species in the family.

Because of the soft structure of spiders, the main record that remains are what is found in amber.

Not much help, but that is my contribution.

[Ukwildlifeo]

I've always found it hard to find out about carboniferous spiders - I think there is some confusion on what fossils are actually early spiders and which are merely related species (usually trigonotarbids - a spider like extinct group). There was one case where a large carboniferous spider turned out to be I think a eurypterid (sea scorpion). I think they define a true spider by the presence of spinnerets.

The usually accurate but not 100% of the time wikipedia has a nice piece on spider evolution here Spider evolution - Wikipedia, the free encyclopedia - it has more info and seems to explain what Ive said but better lol