Tarantulas Vs. "True" spiders

[Profkrakatoa]

Could someone tell me in layman's terms, what the difference is between T's and the "true" spiders? I've read the Taxonomy chapter in The Tarantula keepers guide, but I think I'm going to have to read it a couple of times to digest it.

Mainly I need a way to explain the difference that my middle schoolers can grasp.

 

[Stylopidae]

I had a really good post on this awhile back:

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

 

[Profkrakatoa]

Excellent! Thank you! I haven't mastered the search function yet!
:worship:

 

[Stylopidae]

Excellent! Thank you! I haven't mastered the search function yet!
:worship:

It's your first post...I'll give you a break.

This time.

 

[Pink-Poodle88]

Well, aside from differences in appearance, "true spiders" belong to the sub-order araneamorphae, while tarantulas, trapdoor spiders, purse web spiders, etc. belong to the sub-order mygalamorphae. So in the order aranae which accounts for spiders, you have two sub-orders.

I'd say the biggest difference aside from general size and appearance related differences is the fangs... the fangs in "true spiders" work in a side to side "scissor-like" motion while the fangs of tarantulas and other mygalomorphs work in a downward motion to "pin down" prey. On top of that, the mygalomorphs are among the oldest spiders on earth. Those are some of the main differences and should be easy enough to explain.

 

[PhormictopusMan]

So in the order aranae which accounts for spiders, you have two sub-orders.
.

All good comments but don't forget sub-order Mesothelae, THE most primitive spiders. Liphistiidae is the only family in the sub-order. These spiders still have their dorsal plate segmentation on their abdomens.

--Chris

 

[Pink-Poodle88]

All good comments but don't forget sub-order Mesothelae, THE most primitive spiders. Liphistiidae is the only family in the sub-order. These spiders still have their dorsal plate segmentation on their abdomens.

--Chris

I had thought those were also mygalomorphs, you mean they're a completely different sub-order from mygalomorphs? I still get my taxonomic positioning and the like messed up at times. Aside from the family Liphistiidae, from what I understand, Mesothelae also has some extinct families as well if that counts.

Any other sub-orders I should know about though or are those the only ones?

 

[PhormictopusMan]

Yes it is its own sub-order and yeah, there were other families that are now extinct. I should have said that Liphistiidae was the only living family. It is such an obscure sub-order with only one group found in only one small region of the world that it isn't a big contender, although they are in the hobby now.

I still get my taxonomic positioning and the like messed up at times.

Yeah, same here. It just caught my attention because I just made a table a couple of weeks ago for my website with that information on it. I'm certainly not an expert.

 

[Snakeman4life]

Another difference would be that tarantulas possess four book lungs.