This is a subject I have been thinking on and working on for quite a while and here is my 2 cents.

The Grand Cayman and cayamainsis iguanas evolved from Cuban stock a long time ago (how long I don't know). The fact that even a single iguana landed on the shores of Grand Cayman even once is almost an unbelievable stroke of luck. I would think that the population was started by a single gravid female or possible just 2 or 3 animals (maybe babies who were in a tree hollow) who got washed into the ocean by a storm and clung to debris. with the size and distance to GC is doubtful it would have happened more than once and that is one reason that they are more diverged than the caymaninsis. The caymaninsis is more similar to the Cubans because it is closer and in the same storm if many iguanas were washed into the sea it is more of a chance that more would have landed on LC and CB giving it a larger gene pool and there is the possibility of new animals landing from time to time reinfusing Cuban genes in the population making them continue to resemble Cubans.

Now for the blue part. Blue is a common color among cyclura perhaps 10,000 years ago Cubans were more blue or even if not Cubans have a wide range of color variability many have red bellies but some white and black bellies. Some have dark almost black heads some have brown heads and a very few have slightly blue heads and many of the blue heads have no red in the bellies.

It is my theory that a blue head was the primary originator of GC and over 1000's of years of isolation with no new blood being added the blue jean just expressed itself more and more. Even today the blue in wild Lewisii is not always as pronounced.

This is a many hours discution and the general gist of my idea I will let you all comment and add more as needed.

Rob

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