Most are collected from the 'Coatzacoalcos basin, as you may have seen on the map supplied, so are so called guttulatus stocks!!
There are Pacific side zonatus about, as you saw in the article the type locality zonatus looks very different from the 'Coatzacoalcos' populations. Both populations offered by Conkel are from the head waters of the 'Coatzacoalcos' basin.
You may have read my opinion before, but i believe intraspecific variability applies to many different cichlids and isn't always a trait to class two fish as different species.
The article concludes that sp. 'coatzacoalcos' are probably a regional variation of zonatus, but the problem how i see it is the relationship between guttulatus and zonatus. To my knowledge, the type locality guttulatus has never been caught or studied since Gunther re-described the species in 1869. Seth Meek studied Laguna Amatitilan in 1908 but reported that he couldn't find any fish going by Gunthers description. The type locality guttulatus is lost and a bit of a mystery!!
We could be in the position that zonatus is a regional variation of guttulatus which would then in turn render the latter as both junior synomyns!
As mentioned in the article, until the type locality guttulatus can be caught and studied, then we could be in for a very long wait to classify both species.
Just for the record, your fish is still quite young to give a positive id, however it does show markings characteristic of fenestratus, perhaps a mixture of the two? Its very hard to tell young fish by flash photography as the flash can create alsorts of different colours. Everyone can speculate, but better to let it develop a little more.
Here is a photo of Don's zonatus i used to keep, only a young fish pictured, as you can see the fish shows a lot of characteristics of sp. coatzacoalcos population, they look a little different to Pacific side zonatus populations. See if you can compare your own fish to the photo. Hope it helps?
Cheers,
Lee Nuttall
