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View Full Version : Are Scorpions Related to Lobsters?


ralph124c
05-23-2006, 05:52 PM
I was watching the Animal Planet show about scorpions-they are pretty fearsome creatures. I was wondering if these creatures are related to the marine animals called lobsters. Superficially they look similar, yet they have some big differences-scorpions have stingers on their tails, lobsters have no such glands. Also, they seem to have different head structures. So are these animals related, or are they an example of evolution on parallel paths?

Lemur866
05-23-2006, 06:03 PM
Scorpions are arachnids, so they are more closely related to spiders.http://en.wikipedia.org/wiki/Arachnid

Lobsters are crustaceans, so they are more closely related to shrimp, crabs, roly-polies, and suchlike.
http://en.wikipedia.org/wiki/Crustacean

So they are not particularly related to each other, they are as closely related as crabs are to spiders.

Captain Amazing
05-23-2006, 06:05 PM
Scorpions are arthropods (more specifically, arachnids, like spiders and ticks), as are lobsters (lobsters are more specifially crustaceans, like crabs or shrimp). So, yes, they are more closely related to each other than either of them are to, say, us.

CC
05-23-2006, 06:18 PM
It's important to understand how the various components of the animal kingdom relate to one another. I give you Dave Barry:

http://miami.com/mld/miamiherald/living/columnists/dave_barry/14031886.htm

I don't know how to make this light up as an actual link, but you can figure out how to get there from here, can't you? xo, C.

Polycarp
05-23-2006, 06:18 PM
Scorpions are arthropods (more specifically, arachnids, like spiders and ticks), as are lobsters (lobsters are more specifially crustaceans, like crabs or shrimp). So, yes, they are more closely related to each other than either of them are to, say, us.

Two members of very different classes (even different subphylums) of the same large phylum, Arthropoda. The pincers on the forelimb (different appendage sets giving rise to the forelimbs, IIRC, by the way) are convergence.

The relationship between the two of them is probably not even as close as, say, yours to a shark. (Not an insult, just getting the same-phylum-vastly-different-classes picture firmly in place.)

Crabs, lobsters, and their relations are members of Order Decapoda in Class (or Subphylum) Crustacea. Scorpions comprise Order Scorpionida, and are joined with spiders, harvestmen, mites, ticks, and a few other forms in Class Arachnida, in Subphylum Chelicerata.

By comparison, humans, in Order Primates in Class Mammalia, and sharks, in Order Selachii in Class Chondrichthyes, are both part of Subphylum Vertebrata of Phylum Chordata. To get something as distant from us as scorpions and lobsters are from each other, you'd have to go with the lancelet, the sea squirt, or the salp.

Captain Amazing
05-24-2006, 10:40 AM
By comparison, humans, in Order Primates in Class Mammalia, and sharks, in Order Selachii in Class Chondrichthyes, are both part of Subphylum Vertebrata of Phylum Chordata. To get something as distant from us as scorpions and lobsters are from each other, you'd have to go with the lancelet, the sea squirt, or the salp.

Thanks for putting it better than I could. I never can figure out how to answer a question like that other than "Of course lobsters are related to scorpions. Every living thing is related to scorpions."

Silence of the clams
05-24-2006, 11:03 AM
To get something as distant from us as scorpions and lobsters are from each other, you'd have to go with the lancelet, the sea squirt, or the salp.

Thats a good point, we are related to sea squirts (giggle), since they have a vertbrata as young. They are evolutionary like the string that the european and african swallows use to carry coconuts to north Atlantic shores.

Captain Amazing
05-24-2006, 11:28 AM
Thats a good point, we are related to sea squirts (giggle), since they have a vertbrata as young.

We're related to every other single living thing on this planet.

CookingWithGas
05-24-2006, 11:35 AM
They are evolutionary like the string that the european and african swallows use to carry coconuts to north Atlantic shores.What's the average airspeed? Of the European ones, I mean? ;)

What Exit?
05-24-2006, 11:38 AM
We're related to every other single living thing on this planet.
Are we definitely related to some of the strange creatures found in the sulfuric environments near Sea vents or Methane Seeps? I guess I am specifically thinking down to the Prokaryote level of life.

Jim

BMax
05-24-2006, 11:44 AM
Thanks for putting it better than I could. I never can figure out how to answer a question like that other than "Of course lobsters are related to scorpions. Every living thing is related to scorpions."

Michael Schenker is more closely related to one scorpion than the rest of us. And he came from UFO.

The Chao Goes Mu
05-24-2006, 12:30 PM
The Horseshoe crab is also an arachnid.

Polycarp
05-24-2006, 12:35 PM
The Horseshoe crab is also an arachnid.

Not quite. It's the lone surviving Xiphophoran, same subphylum as the arachnids (and close on being the only other living chelicerate, IIRC) but different class.

Saying that it's the closest living relative of the arachnids is almost certainly accurate, however.

The Chao Goes Mu
05-24-2006, 12:38 PM
Not quite. It's the lone surviving Xiphophoran, same subphylum as the arachnids (and close on being the only other living chelicerate, IIRC) but different class.

Saying that it's the closest living relative of the arachnids is almost certainly accurate, however.

Thanks for the clarification mate. :)

Darwin's Finch
05-24-2006, 12:45 PM
By comparison, humans, in Order Primates in Class Mammalia, and sharks, in Order Selachii in Class Chondrichthyes, are both part of Subphylum Vertebrata of Phylum Chordata. To get something as distant from us as scorpions and lobsters are from each other, you'd have to go with the lancelet, the sea squirt, or the salp.

To be honest, this would (and does) tell me nothing about relative relationships. The ranks are meaningless. What does tell me something about the relative distance is the following:

Scorpions, belonging to the Scorpioniformes branch of the Arachnida clade, appear in the fossil record around the Carboniferous Period (299-359 million years ago). The sister group to Arachnida, Pancrustacea (a proposed grouping of Hexapoda + Crustacea, supported by molecular data), contains our friend, the Maine Lobster. Lobster fossils have been found in the same limestone quarries that gave us Archaeopteryx that look pretty much exactly like modern lobsters. This puts lobster origins at around 200 to 146 million years ago, at least.

Now, since Chelicerata, to which arachnids belong, is an ancient group -- fossils extend back to the Cambrian -- this means the most recent common ancestor of lobsters and scorpions dates back to at least that far. Which means we're looking at roughly between 200-300 million years worth of divergence between the two groups.

MizGrand
05-24-2006, 12:54 PM
Lobsters sure look like underwater bugs though. I loves me some good lobster, until I start thinking about how it kinda resembles a spider. Yikes!

Darwin's Finch
05-24-2006, 01:02 PM
The sister group to Arachnida, Pancrustacea (a proposed grouping of Hexapoda + Crustacea, supported by molecular data), contains our friend, the Maine Lobster.

Correction: "The sister group to Chelicerata, Pancrustacea...". Arachnida lies within Chelicerata, of course.

Edward The Head
05-24-2006, 01:16 PM
Michael Schenker is more closely related to one scorpion than the rest of us. And he came from UFO.

Actually he was a Scorpion before he went to UFO, he was on their first album, Lonesome Crow, and then came back for Lovedrive.

Malienation
05-24-2006, 05:23 PM
Fun fact about scorpions: although nobody knows why they have developed this way, the exoskeletons of scorpions are fluorescent, i.e., they glow under ultraviolet ("black") light.

Polycarp
05-24-2006, 05:49 PM
Fun fact about scorpions: although nobody knows why they have developed this way, the exoskeletons of scorpions are fluorescent, i.e., they glow under ultraviolet ("black") light.

Obviously, they were planning ahead for their career in hard rock; see BMax and Edward the Head's posts! ;)

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