One of the reasons I moved to, and keep Panamanian biotope tanks, is Panama seems to be a tiny hotbed of evolution.
There are species here, that don't exist in either South America, or north in Central America, and these species may have only taken 3 million years to develop.
The time since the countries of Panama and Costa Rica emerged from the sea, thru either plate tectonics, or volcanism (or both).
Darienheros calobrense, and Isthmoheros tuyrensis, are each cichlids in a a monophillic genus, and each are only found in snd slightly east of the Darien in eastern Panama.
There are also a number of species here that originated in South America, and migrated here, and over that 3 million years, remain part of their S American genus, and that evolved into separate species.
Andinoacara coerleopunctatus, only member of the genus to be found this far north, but has at least 6 remaining species in S America.
Chaetostoma fischeri, found in the same area of Panama, is a genus containing at least 6 other species, only found in S America
And Ctenolucius beanii, found here, but the only other species (hujueta) found in S America
There are also killifish that survive dry spells here, by hunkering down, and laying eggs in the water storage spots in certain trees.
There is another man induced accidental experiment going on here too.
6 Cichla occellerus escaped from a pond in the 1960s, and have now become a major cichlid apex predator in Lake Gatun, eliminating many of the native cichlid species.
They have changed little in that 70 + years, except...that they seem to grow smaller in the higher pH, harder water of Gatun, than they do in the soft, low pH waters of Amazonia.
Another is the Oscar that has a significant presence in lake Gatun, probably released by aquarists when they outgrew tanks, our decades.
Another soft water, low pH species, where perhaps only 1 or 2 of each spawn of thousands were able to survive, but have adapted to its high pH hard waters to become a major player in the lake.
It'd be interesting to compare and check if, or how each of these DNA has changed from its ancestors, in these longer term happenstance situations.
