Posted by:
chris_harper2
at Mon Sep 13 10:10:49 2004 [ Email Message ] [ Show All Posts by chris_harper2 ]
In some cases determining convergence from parallelism may be difficult. The Green Tree Python and Emerald Tree Boa example is the one most often put forth for convergence. But in all the pet-trade books they discuss this phenotype as a single trait. But in actuality, is it really fair to say green coloration, the similar looping of coils, and all the other similarities form one trait (let's call it the green arboreal Boid condition).
Maybe the green coloration evolved in parallel, but some of the other similarities are examples of convergence.
I believe the enlarged, grooved teeth in many rear-fanged snakes is an example of convergence as this condition has several independent origins in snakes.
In other words opistoglyph condistion is homoplasic.
Homoplasic traits are a bit different from analagous traits. I believe homoplasic traits can evolve from pre-exisisting traits that evoloved in parallel (snake teeth in this example) but are homoplasic because the trait had more than one origin.
I should probably stop here before I get in over my head 
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1.1 Gonyosoma oxycephala - (Silver/Yellow)
3.4 Gonyosoma oxycephala - (Green)
2.1 Gonyosoma janseni - (Black)
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Convergent evolution in snakes... - chris_harper2, Mon Sep 13 10:10:49 2004