What is this spider?

The other day I saw a fairly large spider with bright red spikes on its body. I’ve never seen spikes on a spider before, what is it and is it poisonous?

Could be a jewelled spider (scroll about halfway down to see some with red spikes. These are primarily found in tropical and subtropical areas.

Without a photo its difficult to positively ID. I was going to suggest it could be a Horned Orb Weaver or a Kite Spider, but these spiders are normally only found in Africa and possibly Asia. By your description, I would guess at it being an orb weaver, and most likely not at all dangerous to humans.

Heres a photo of the Kite spider I described. This one has white spikes, but they also come with red spikes. Is the one you saw look anything like these?

Forgot the link:

http://www.bushveld.co.za/pictures-of-kite-spider.htm

FYI, the jewelled spider and the kite spider are the same genus (Gasteracantha). Search for “Gasteracantha” and you’ll find many examples.

http://www.doacs.state.fl.us/pi/enpp/ento/venomousspiders.htm#recluse

It looks like maybe Gasteracantha elipsoides - the text said they’re found in Florida. When I get my digital camera back I’ll take a pic if the little fella is still there.