many years ago, I saw a large rodent on the bank of a creek in a highly urbanized area. For years I explained what it was to people and they would tell me it was either a groundhog, or a muskrat. Well, I knew what I saw and it didn't match the description of either, nor did it look like the pictures in books. This thing had a flat tail...I know, immediately people say "beaver". Well, it wasn't because it's tail was only 1 to 2 inches wide and was widest at the base and tapered to the tip...like a knife of some kind...sorta like the one they called an "arkansas toothpick". I can't even begin to tell you how much time I spent looking through books and the internet trying to find a picture or a description that matched.
Then one day, by accident, I happened to see a footnote in a description of muskrats in a fairly old book. It went something like this: In certain locales, there are reports of some specimens growing much larger and having slightly flattened tails, but not like a beaver's tail.
immediately I went "AHA!"
Wildlife is amazing. The diversity is amazing. I really beleive that there are animals out there that you can't find in a book. It may not be that it's a new species, just an individual with not quite "textbook" characteristics or markings. I once saw a red fox that I would swear on a bible had what dog breeders call a "brindle" coat. At first I thought is was something no one had ever seen before, but as I watched it, it became clear to me it was just a red fox with really, REALLY, weird color markings. This particular fox also had unusually short fur for a red fox, and it was quite skinny. At first, I thought is was some kind of new species of wild cat.