"Paleozooogy" is not a real word.
Type it into a search engine, and you'll get about 700 hundred hits. It must be a real word, right? Look, it's defined here: "The science of extinct animals, a branch of paleontology.". Definitely a real word.
Check the other pages: they all have the exact same definition, attributed to Webster's 1913, an American dictionary that is conveniently out of print and out of copyright. Somewhere in the process of converting this dictionary to electronic form, a typo entered the process. Clearly, this should be 'paleozoology', but someone forgot to press the 'l', or it never got scanned properly. To check this, I got my more recent (1962) edition of Webster's and looked it up: no 'paleozooogy', but definitely 'paleozoology'. The electronic form of this type has now been copied round a few hundred times, but all from one flawed source.
So, paleozooogy. Not a real word.
Which is a shame, since I could really have done with a real non-onomatopoeic word that has three o's in a row next to each other. But alas, it seems destined not to be. Booooo!