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Jurassic Beaver

"Looking as if it was put together from pieces of platypus, river otter, and beaver, the creature was nearly half a metre long and weighed about half a kilogram."

I grew up with imperial measure, so I'm translating on the fly here, but doesn't that make it about 19 inches long, and only 1.1 pounds?

Robert
 
Pope130 said:
"Looking as if it was put together from pieces of platypus, river otter, and beaver, the creature was nearly half a metre long and weighed about half a kilogram."

I grew up with imperial measure, so I'm translating on the fly here, but doesn't that make it about 19 inches long, and only 1.1 pounds?

Robert
Click to expand...

Your math is correct. About half of the critter's length is tail, but it just seems too light.
 
Question is- is this ancestral to any modern aquatic mammals, or just an example of parallel evolution? (Compare dolphins and ichthyosaurs for example).
 
Soapy Sam said:
Question is- is this ancestral to any modern aquatic mammals, or just an example of parallel evolution? (Compare dolphins and ichthyosaurs for example).
Click to expand...

From here
http://www.sciencemag.org/cgi/content/abstract/311/5764/1123

It appears to be a docodontan mammaliaform.

The docodonta are one of the branches of mammal-like creatures which diverged from the stock leading to the true mammals

http://www.palaeos.com/Vertebrates/Units/Unit420/420.100.html#Mammaliformes


This would imply that Castorocauda is either ancestral to all modern mammals (if it occurred before or on the point where the lineages diverged), or none of them (if it occurred after).

It's almost certainly convergent on modern aquatic mammals.
 
Soapy Sam said:
Question is- is this ancestral to any modern aquatic mammals, or just an example of parallel evolution? (Compare dolphins and ichthyosaurs for example).
Click to expand...
From the reconstruction, I would say that it is simply a reasonably efficient shape for swimming, much as otters and beavers are. The evolutionary pressures on any aquatic mammal are going to be similar: streamlining means that it needs less effort to swim and will be better at catching prey/evading predators, and webbed feet are obviously going to be pretty handy underwater, as is a paddle-like tail.
 
sphenisc said:
This would imply that Castorocauda is either ancestral to all modern mammals (if it occurred before or on the point where the lineages diverged), or none of them (if it occurred after).

It's almost certainly convergent on modern aquatic mammals.
Click to expand...
Well, you say that, but I read in the Metro this morning (a free rag given away on public transport) that it's going to cause scientists to have to rethink the theory of evolution. Now if that isn't a clear warning from god, I don't know what is. The latter is, I agree, more likely.

Cheers,
Rat.
 
Rat said:
...that it's going to cause scientists to have to rethink the theory of evolution.
Click to expand...

Don't know why it would cause them to rethink the entire theory, just the part about what we know about the earliest mammals.
 
Beavers.

....


Hans
 

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