I don't see much need for this to be a sort of article for the site. However, since you feel other RPs miss out on these unique creatures, you should make one yourself. There are plenty of threads in this section about GMing if you're concerned about such. Furthermore, you can find someone who likes your idea and would work with you. Your best bet is to just make an Interest Check (probably in Advanced as that is where I see this fitting best) and ask there what people might find most interesting to play. 

I think "Authorial Advice" should be something more like "Pedestrian Accounts." Instead of making it clearly about your opinion and someone having to read "rambling," you could write it in a way that gets your opinion across, and even counter-points to make it interesting, but seems to be coming from innocents running into these creatures (and somehow surviving). Maybe key opinions of their "race" from other 'thropes.
I also think "Level of Danger" could be renamed to "Lethality" as a more intense term, but that's a needless suggestion. However, I think numbers should be used instead of asterisks. Also, what do those numbers mean? Perhaps it's best to not have a scale and just to simply describe it and compare it to a few other things but in the most generalized manner as to not give it strict comparisons. I just know that numbers don't really work in PbP RPing.

But going along with Cain, it'd be interesting to see such odd animals: dolphins, otters, seals, walrus, etc.
Are fish not allowed? Sharks, eels, puffer fish, etc.
What about reptiles? Snakes, lizards, salamanders, etc.
What about avian creatures? Hawks, eagles, pigeons, hummingbirds, etc.