# How closely releted are scorpions and lobsters?



## Dr. Octopus

I saw an interesting documentary  on Discovery channel about prehistoric fish and other ocean dwellers- there was a segment on giant prehistoric scorpions that lived in the ocean, and scurried about on the sea floor- they looked like modern scorpions- but were gigantic....

Speaking of the ocean- Are scorpions at all related to lobsters and crabs? They all have pincers, and all seem to have a similar ways of chewing and eating food- is the resemblance pure coinidence, or do they share a common ancestor?


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## LoganVivisected

Scorpions

Kingdom: Animalia

Phylum: Arthropoda

Subphylum: Chelicerata

Class: Arachnida 

Crabs and Lobsters

Kingdom: Animalia

Phylum: Arthropoda

Subphylum: Crustacea

Class: Malacostraca 

all coinidence, the similarities end at the subphylum, which is a huge difference when you get technical.


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## fusion121

Both lobsters and scorpions are arthropods, so they will share a common ancestor, though it will have been 100s of millions of years ago. I think the jury is still out on the exact nature of the deep relationships within the arthropods. However the evidence from molecular data would suggest that the Chelicerata (to which the scorpions belong) is an evolutionary more primitive group then the Pancrustacea (lobsters, crabs etc.).


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## Dr. Octopus

fusion121 said:


> Both lobsters and scorpions are arthropods, so they will share a common ancestor, though it will have been 100s of millions of years ago. I think the jury is still out on the exact nature of the deep relationships within the arthropods. However the evidence from molecular data would suggest that the Chelicerata (to which the scorpions belong) is an evolutionary more primitive group then the Pancrustacea (lobsters, crabs etc.).




Interesting stuff- Perhaps the scorpions are more closely related to horseshoe crabs, the 'living fossil', which i think is related to spiders and scorpions..


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## EAD063

Dr. Octopus said:


> Interesting stuff- Perhaps the scorpions are more closely related to horseshoe crabs, the 'living fossil', which i think is related to spiders and scorpions..


Yes, scorpions (spiders I don't know), closest relative is the horseshoe crab.  Both share a very similar anatomy.   I looked into it a bunch when I was first a member, someone had just posted a picture of they're scorpion submerged in water for a long period of time and I wanted to see if there was some oxygen absorption possible or not.  As to not interupt the thread, the conclusion was probaly not, and "I'm not qualified or knowledgable enough to even consider such and idea." 

But yes, to the best of my knowledge you are correct.  Do a quick google of the horseshoe, pretty interesting.

EDIT: oops, I wanted to add that both previous elaborations probaly hold more ground and fusions example of them being millions of years of evolution apart should definently be weighed more heavily when considering they're currect realtion/similarities.


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## Dr. Octopus

EAD063 said:


> Yes, scorpions (spiders I don't know), closest relative is the horseshoe crab.  Both share a very similar anatomy.   I looked into it a bunch when I was first a member, someone had just posted a picture of they're scorpion submerged in water for a long period of time and I wanted to see if there was some oxygen absorption possible or not.  As to not interupt the thread, the conclusion was probaly not, and "I'm not qualified or knowledgable enough to even consider such and idea."
> 
> But yes, to the best of my knowledge you are correct.  Do a quick google of the horseshoe, pretty interesting.




Interesting- the horseshoe crab is so perfectly adapted to its envoronment it has not experienced a physical alteration it's evolution in hundreds of millions of years- It would be interesting if it turned out that the direct ancestor of scorpions looked exactly like horseshoe crabs- and some of those horseshoe crabs that remained in the watrer produced generations of offsping that retained its original appearance, and others that moved onto the land produced descendants that  evolved and adapted to a terrestrial environment- thus producing the scorpions we all know and love so dearly...


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## EAD063

Dr. Octopus said:


> Interesting- the horseshoe crab is so perfectly adapted to its envoronment it has not experienced a physical alteration it's evolution in hundreds of millions of years- It would be interesting if it turned out that the direct ancestor of scorpions looked exactly like horseshoe crabs- and some of those horseshoe crabs that remained in the watrer produced generations of offsping that retained its original appearance, and others that moved onto the land produced descendants that  evolved and adapted to a terrestrial environment- thus producing the scorpions we all know and love so dearly...


I have a feeling the split took place in the sea. The horseshoe seems far to adapted to aquatic life to be able to surive and evolve on land.  I'm no scientist though and there are much more intelligent people on here when it comes to this stuff.


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## Brian S

Dr. Octopus said:


> Interesting stuff- Perhaps the scorpions are more closely related to horseshoe crabs, the 'living fossil', which i think is related to spiders and scorpions..


That has actually been debated before.


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## fusion121

Horseshoe crabs are Chelicerates and so are closely related to scorpions, much more so then lobsters. The likely shared a "recent" common ancestor.


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## Dr. Octopus

Brian S said:


> That has actually been debated before.




sorry, i'm new here...Is there a list of questions I shouldnt ask, as they've been addressed in the past?


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## Brian S

Dr. Octopus said:


> sorry, i'm new here...Is there a list of questions I shouldnt ask, as they've been addressed in the past?


You misunderstood my reply which is partly my fault for not answering completely. I am not sure if it has been debated here or not but I do know it has been debated by those from the scientific community.
There isnt a list of specific questions to not ask here. Some questions get asked over and over however it is sometimes a bit difficult to find your answer as some dont title their posts where a search will do much good. If I have a Q I usually search but if I dont find the answer I am looking for I will ask the question. I hope that makes sense. Welcome aboard


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