You might conclude that, depending upon the characteristics of the two snails. It is limited, as different species, genetically isolated, look to us like the same species at first in the fossil record. We only call them different species when the bones are different, when in fact speciation happens long before significant (or any) bone differences.
For example, if there is an unusual aspect of calcium deposition on the inside surfaces, or a curious shape in the chamberization (all fossilizable) and B has this like A does but no others, it's a good bet that B came from A. The details make all the difference, of course.
The effect of this is to make species appearance more "sudden" than it really is. The B snail could have had different feeding habits, coloration, tidewater instead of deepwater for marine species, all sorts of possibilities that don't necessarily reflect in the shells themselves.
Gould was a mollusk fellow; they spoke deeply to him. I'm more of a reptile guy myself. ];)
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timeasmymeasure
Re:
Date: 2002-11-19 05:38 pm (UTC)For example, if there is an unusual aspect of calcium deposition on the inside surfaces, or a curious shape in the chamberization (all fossilizable) and B has this like A does but no others, it's a good bet that B came from A. The details make all the difference, of course.
The effect of this is to make species appearance more "sudden" than it really is. The B snail could have had different feeding habits, coloration, tidewater instead of deepwater for marine species, all sorts of possibilities that don't necessarily reflect in the shells themselves.
Gould was a mollusk fellow; they spoke deeply to him. I'm more of a reptile guy myself. ];)
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