> if you put Pseudomugil inconspicuus in fresh water it dies. I have
> tried a few times to convert them over.
The trick question is where do the marine species fit relative the freshwater
ones in a phylogeny. If the freshwater ones are basal then the marine ones
invaded from freshwater, if basal ones tend to be marine then that suggests
the group arouse in marine habitats. It would be interesting to know if the
marine ones are all more closely related to each other. I'm starting to play
around with some of these questions in blue eyes, but it's a lower priority at
this stage.
Cheers
Peter