Fossil spiders!

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i have mygalomorphs living in my room right now. those big, powerful spiders are a thing of beauty.
H. lividum is a particularly beautiful creature amongst many.

also, check out the solfugids, the infamous "camel spiders". tip: they do not get bigger than 6". they are not poisonous. they cannot jump.
they are amazing animals though.

I recently heard a hypothesis (I have no idea whether there is any basis for it or not) that spiders (or some 8-legged ancestor of spiders) evolved before 6-legged insects. The wings of insects are (according to this hypothesis) a mutation of two of the legs of the pre-spider, leaving 6 legs.

Does anybody know whether this is generally accepted or not?

The part I liked was, "thus this occurrence extends the family record by some 90 myr". What a thrill for Selden et al.

My education here is continuing apace. 'Lagerstätten' is now part of my reading vocabulary.

Thank you PZ.

By JohnnieCanuck (not verified) on 29 Jul 2006 #permalink

Ewww.

I don't like spiders.

That's certainly an interesting idea, insects evolving from arachnids, but there's good reason to think otherwise, that insects are instead most closely related to crustaceans.

Insect segments:

1: H1: Eyes
2: H2: Antennae
3: H3: none (crustaceans: second pair of antennae)
4: H4: Mandibles (mouthparts)
5: H5: Maxillae (mouthparts)
6: H6: Labium (mouthpart)
7: T1: Legs, wings in very early insects
8: T2: Legs, wings
9: T3: Legs, wings
10: A1: none (crustaceans may have additional pairs of legs)

Arachnid segments:

1: H1: Eyes
2: H2: Chelicerae (fangs)
3: H3: Pedipalps ("arms")
4: H4: Legs
5: H5: Legs
6: H6: Legs
7: H7: Legs
8: A1: none

H = head / prosoma
T = thorax
A = abdomen / opisthosoma

So spiders walk with limbs that insects eat with.

By Loren Petrich (not verified) on 30 Jul 2006 #permalink

probably too late for anyone to read this, but hereis Megarachne, the monster fossil spider.
Isn't there a limit on the size land-based invertebrates can reach? what about land-based invertebrates that molt in the sea? that could make for some big bastards.

i love spiders

oh i say

lookin at these spiders makes me even scared than what i was so why show them. the people out thare that has a phoia of them and you still show them WOW there spiders you dont see them puting pictures of you all over the computer so why do it. i just dont no why people think that they have the right to do something like that at the end of the day some might bite because people are winding them up takeing pictures i dont see many people takin pictures of ants etc....... WHY DO IT .ITS WRONG IN MY EYES............

i don't like spiders but i do like turtles so i am happy with a turtle any day

I hate spiders! Ewwwwwwwwwwwwwwwwww! They are so gross how could you like them?