is this a tarantula or a spider?

[Freddie]

What makes the starter think that it's not a tarantula (or a birdspider, which is the same thing)?

Spiders belong to Arachnida, which is the class of Arthropoda. Subclasses (orders) of Arachnida are Acari, Araneae (spiders belong here!), Opiliones, Pseudoscorpionida and Scorpiones.

So the Araneae is the order where are all the spiders.
Like Theraphosa blondi is a tarantulas and taxonomy goes like: Class: Arachnida, Order: Araneae, Suborder: Mygalomorphae, Superfamily: Theraphosoidea, Family: Theraphosidae, Subfamily: Theraphosinae, Genus: Theraphosa, Species: blondi.

Latrodectus mactans goes like: Class: Arachnida, Order: Araneae, Falmily: Theridiidae, Genus: Latrodectus, Species: mactans.

 

[cacoseraph]

a word on spiders:
there are like, two fundamental types of spiders:
mesothelae - ancient living fossil spiders. retain abdominal segmentation (vice the nice, unified, smooth abdomen of a widow or tarantula). lack venom glands.
opisthothelae - the rest of spiderdom. broken into two groups:
. . mygalomorphae - next oldest suborder. generally large, hairy spiders. possess at least one pair of book lungs to breathe with (i think most/all have two pairs of book lungs, actually). used to be known as Orthognatha because of the mostly parallel arrangement of the fangs. make one type of silk only.
. . araneomorphae - most common spiders. most evolved. seven different types of silk present in representative species. use "newer" ways to breathe, vice book lungs. fangs at rest cross each other. used to be known as Labidognatha. i think that might mean something like "lip jaws". gnatha means jaws at any rate =P


a word on tarantulas:
the word "tarantula" comes from a spider in *italy* known scientifically known as Lycosa tarantella. when explorers to the new world saw theraphosidae spiders they called them tarantulas after their home grown large and hairy spiders. commonly in the USA we call only spiders in the family Theraphosidae tarantulas. in other parts of the world any spider in the Mygalomorphae order is considered a tarantula. neither the "just theraphosidae" or "all mygalomorphae" defintions are "really" correct though, considering the orginal usage was with a freaking Lycosidae family spider!

 

[Stylopidae]

http://www.arachnoboards.com/ab/showpost.php?p=1015416&postcount=6

Since you found that picture in the 'Tarantula' gallery, the location gives you the answer.

Rather pointless, if you ask me.

If you'd like to compare and contrast between araneomorphs and mygalamorphs, above is a good place to start.

 

[penny'smom]

I find it kind of funny that the image the OP posted was one of Eric's own. Just an observation. Perhaps that's why the OP was advised to ask Eric what it was.

 

[DrAce]

That would depend on your definition of 'spider'. True spiders are much more advanced then tarantulas, by evolutionary standards, and therefore represent the pinnacle of their line. Whereas tarantulas and other mygalmorphs are the more 'basic'.

Kind of like the little sharks you see in fishtanks, and the ones you see in the ocean you think of as 'real' sharks.

-Sean

It's a common mistake to assume that because something diverted from the evolutionary tree a long time ago, it is somehow more 'primative'. Every organism on earth (with a few exceptions) is just as evolved as every other. Organisms generally don't freeze evolution - so a tarantula is not more 'primative' than any other spider... nor are they less evolved.

They are more distant ancestors of the others... in that they branched off the tree a while before the other spiders did their speciation (which is also a little bit of a lie, but for what I'm trying to get across, it'll do).

I suspect you know all this, Sean, so I'm kinda preaching to the converted... but I thought, since I'm bored, that I'd catch you on your terminology.