If you go to cichlidae.com click on catalog, cichlids, central american, exCichlasoma, uropthalmus, there are 10 subspecies listed.
and if you go to to articles, central american and scroll down, you will find an article called
The Mayan Cichlid, Cichlasoma uropthalmus, an overview by Roberto Carlos Medina Barrientos 2003
who is doing research on uropthalmus and explains the why of subspieces breakdown.
And my personal experience snorkeling in the cenotes of Mexico, I was amazed to see the difference between coloration, shape and looks from one cenote to another, and between brackish, and those living in pure seawater.
In fact when I first saw them in cenote Escondido, I mistook them for synspillum.
Back in the 80s I saw a subspecies living in the mangrove area of Isla de Mujeras that even then, was known as Cichlasoma troeschelli, and looked quite different than the mainland variety.