I have tried to make sense out of the nomenclature / classification of these birds.
I had some excellent assistance in this regard from Robert Pittell, my former pediatrician.
Among other places, both the Porphyrio martinicus and Porphyrio porphyrio can be found at Green Cay in Boyton Beach.
Porphyrio martinicus is a new world bird.
It is also known as the Purple gallinule, although it is not actually in the genus Gallinula.
It is also known as a purple moorhen, although most of the moorhens are actually in the genus Gallinula. And there are also males even though they are called hens. Hmmmm.
Oh yeah, there is also a great deal of confusion on the web as to whether the species is P. martinicus or P. martinica.
Porphyrio porphyrio is an old world invader. It is also called a purple swamphen, even though, as noted, that includes the males. According to Wikipedia, it is also called in various places "Purple Moorhen, Purple Gallinule or Purple Coot." And, yes, except for the coot part, that is identical to Porphyrio martinicus with all the caveats listed above.
And to make matters worse, the American Coot (Fulica americana) is in a different genus and is also known as a mud hen.)
Moor? Swamp? Mud? Apparently, moorhen are sometimes called marsh hens or river chicken. Ugh! This is fowl indeed.
What bird brain named these?
Perhaps that is why scientists used the Latinized names.
The only problem there is that many taxa have just undergone reclassification and naming due to newly acquired DNA sequence data.
For example, some of the Porphyrio used to be Porphyrula.
So you really cannot win on that score either.
Despite all my railing, at least they are all in the family Rallidae.