The largest spder ever?

[tarantula3898]

OK so there is an entry in the guiness book of world records for the largest spider fossil ever found, the reports say that even though the ends of it's legs are not part of the fossil it is estimated that the spider reached about 20 inches across.

So now why on earth is there no record of the worlds largest spider that lived during this era?



http://www.nature.com/nature/journal/v433/n7028/images/433792a-i2.0.jpg

 

[seanbond]

yeah thats interesting, who knows?

 

[David Burns]

It takes a long time for a spider in our era to become a fossil.

 

[M.F.Bagaturov]

The answer is simple: the tarantula ancestor was very small...

 

[DeTwan]

A little confused by your question, but intrigued

I think you need to define era b/c for some an era is 10yrs to 500yrs.
Isnt the Goliath one of the biggest with other bird eaters competing over who is largest in this era , the 21 century?
Sry I dont know any of their scientific names. Big spiders dont appeal to me.

 

[G. pulchra]

I'd like to see a picture of the largest Tarantula alive today.

 

[Sabatta]

Since he said our era I assume he means the cenozoic era - 65 million years ago until today - so it is possible that this fossil is from our era.

Is it possible to post a link to the original article?

 

[M.F.Bagaturov]

http://www.nature.com/nature/journal/v433/n7028/full/433792a.html

 

[Moltar]

Sea scorpion huh? I didn't know there was such a thing. I figured that was what we'd call a lobster... lol

 

[Sabatta]

http://www.nature.com/nature/journal/v433/n7028/full/433792a.html

Ah thank you. The article classifies it as a sea spider.

 

[Aragorn]

Back in prehistoric time there was far more oxygen in the atmosphere, so a lot of arthropods grew big. The reason for it is land arthropods have very primitive respiratory system for taking in oxygen. They rely on defusion of air into the brook lungs in the abdomen rather than rely on the diaphram, like us, to contract and draw in the air so the blood in our lungs can assimilate the oxgygen. Defusion means movement of gas or liquid from higher concentration to lower cocentration. When the air in the brook lungs are concentrated with carbon dioxide gas and the oxygen gets used up the carbon dioxide move from higher concentration, the lungs, to outside of the lungs, and then when there are less oxygen inside the lungs, the oxgen from the air outside, which have higher concentration of oxgen, slowly move in. This process keeps going on and on and on.... Now, with a bigger body arthropods would need more oxygen which there is not a lot of today, so they all adapted and evolved to be smaller because their respiratory system isn't just efficient enough and their blood doesn't have iron, like ours, which assimilate oxygen better, but rather arthropods' blood is copper based which isn't as efficient at assimilating oxygen as our iron based.

 

[Aragorn]

Did you know in prehistoric time the dragonflies have two foot wing span? And the ancestors of todays spider and tarantulas were much larger than the largest tarantulas today.

 

[M.F.Bagaturov]

Sorry Aragorn, but this doesn't consider for spiders (Araneae).
As opposite it is consider that the prehistoric spider was very small.

 

[the nature boy]

the nature boy

It would be interesting if there was somewhere on the boards where anyone with a particularly large T could post pictures. Perhaps "the largest ever" of a given species would show up.

--the nature boy

 

[lucanidae]

Back in prehistoric time there was far more oxygen in the atmosphere, so a lot of arthropods grew big. The reason for it is land arthropods have very primitive respiratory system for taking in oxygen. They rely on defusion of air into the brook lungs in the abdomen rather than rely on the diaphram, like us, to contract and draw in the air so the blood in our lungs can assimilate the oxgygen.

There's a couple of misconceptions here and it's propagated by the popularity of the argument about O2 concentration on these boards. First of all, 'most arthropods' do not breath through book lungs. 'Most arthropods' going on diversity and species number use trachea. Also, the O2 saturation hypothesis is only that, a hypothesis. It has just as many flaws as other hypothesis and not much supporting data. At this point it's correlation...not causation. Also, it doesn't apply here because this animal (if it really was a Eurypterid) was aquatic, and the O2 saturation of the oceans hasn't changes nearly as much as the atmosphere.

As for this:

As opposite it is consider that the prehistoric spider was very small.

I've never heard this before. I don't think they've found the closet common ancestor to the spiders and the (amblypygid+uropygid etc) clade...so I don't see how you can make a statement that the ancestors of spiders were small. If fact, there are some fossils that are extremely Mesothelid-like and quite large.....like the size of a basketball.

And to speak to the original poster, it's really hard to accurately document the limit of something, because you never know if it could grow a little bigger, run a little faster, or whatever. Fossils however, are pretty static.

 

[M.F.Bagaturov]

Hello Lucanidae!

I'm sorry , I can't give You the detailed description but maybe soon I will re-write the evolution page on my site.
Right now for better understanding I can suggest You to read the following articles:
1. WUNDERLICH, J. 1988. Die Fossilen Spinnen im Dominikanischem Bernstein. Beitr. Araneol., 2: 1 378.
2. P. A. Selden and J. Gall. 1992. A Triassic mygalomorph spider from the northern Vosges, France. Palaeontology 35(1):211-235 [D. Smith/A. Kinchloe/A. Kinchloe] – this is the description of the Rosamygale grauvogeli:
http://homepage.mac.com/paulselden/Sites/Website/Rosamygale.pdf
3. Newsletter of the Invertebrate Special Interest Group, CBSG, India & South Asia. Vol. 5 No. 2, December 2001
4. David Penney & Daniel E. Pérez-Gelabert (2002) COMPARISON OF THE RECENT AND MIOCENE HISPANIOLAN SPIDER FAUNAS. Revista Ibérica de Aracnología, Vol. 6, Pp: 203–223. It is listed the fossil Ischnocolinopsis acutus in Theraphosids for Hispaniola.
5. Penney, D. & Selden, P. A. 2007. Spinning with the dinosaurs: the fossil record of spiders. Geology Today 23, 231–237
6. Vollrath, F. & Selden, P. A. 2007. The role of behavior in the evolution of spiders, silks, and webs. Annual Review of Ecology, Evolution, and Systematics 38, 819–846
This is gives You the clue on the modern view of the prehistoric spider.