gholland;113176 said:I assume that zonatus can't brood multiple times, which would mean that chierchiae developed that ability over the last 2 million years if what Nesis says is true?
monty;113182 said:That all could be right, or it could be more complicated. As an example, since some cuttles and nautilus (and I think some squids) lay eggs over a longer time, and don't brood in a big batch like octopuses, it's possible that the ancestral coleoid was able to breed multiple times, and that something pressured other octopuses to lose that ability, but for some reason chierchiae kept it, or some octopuses have kept a vestigial mechanism that was somehow "turned back on" by a lucky mutation or some unusual environmental pressure. As far as zonatus, it's quite possible that no one has ever raised them in a lab or observed them long-term in the wild, so no one knows if they have this ability or not.
I wanted to continue this discussion without completely hijacking Jon's thread...
The next question I have is whether the genetic analysis might be able to indicate when this egg-laying habit was lost (or gained) and how that timing related to the development of a bottom-dwelling life (or do I have that backwards too?) and the loss of a shell.
Seems like you might not need to lay as many batches of eggs when you have the ability to crawl into well-hidden, easily defendable spaces. Maybe?