No, it's not A. siquia, I can say that for certain having kept and bred that species. It is clearly Central American in origin. I hate to jump to the H-word, but that would have to be my guess without doing some serious research. And some sort of hybrid seems to be most likely, anyway.
Edit: I should like to add that no Amatitlania species has a large round spot on the flanks. Rainbow Cichlids do, but it's got the wrong head shape for that species.
I defer to chrome on this one. Head shape actually looks to pointy to be any full-blooded convict types.
Did a little extra checking this AM, I think it might be one of the Cribroheros species, which used to be placed in Astatheros/Amphilophus after the breakup of Cichlasoma. The slightly posterior placement of the large flank spot is typical on several species of this genus, and some of the species have been in the hobby, though uncommon. Some possibilities would be alfari, longimanus (most common of the group), rhytisma, robertsoni, and rostratus.
Unusual but lucky find if this is correct, and I now believe it is the best guess. Most of these species are quite attractive as adults. I spawned longimanus quite some time ago, it has been common in the hobby at times, though not lately.