I can't locate a "barrel spider" in Wikipedia or via a quick Google search (beyond those that have appeared in videogames). Any ideas upon what this is based?
Yes I do.
When I was doing my own take on that Dragon article's spiders trying to figure out what arachnid the author was talking about caused me considerable puzzlement, but after a lot of Googling I came across an article that used the name "Barrel Spider" for a
Solifugid (aka sun spider, camel spider, wind scorpion).
Once I saw that everything else clicked - the long pedipalps, the powerful jaws, the yellow body with sensitive hairs, the
hissing and the lack of any mention of poison (since Solifugae are non-venomous*).
*Well like most things in nature there may be a few exceptions, since there's a study that claims one species has venom glands.
Now Solifugae are arachnids but are not true spiders, those of you with access to Dragon #67 will notice that the "Souping Up The Spider" article included several definite non-spider arachnids, the "Daddy Longlegs" harvestman (
Opiliones) and the "Whip Spider" (
Amblypygi), which makes it more likely the "Barrel Spider" is another one.
All in all, I'm pretty certain the "Barrel Spider" is a Solifugid.
Although what really puzzles me is why it's at the start of the "Weavers" entry, since there's no mention of it producing silk in its entry and sun spiders don't spin webs.
Incidentally, I vaguely recall seeing some or all three of these spider-kin an official WotC 3E product, but I can't remember which one - maybe a Drow supplement? Failing that, Necromancer Games' Tome of Horrors has 3rd edition conversions of them.