You can scan the animals for units & upload them in the discovery menu for nanites, renaming them in the process should you wish to.

When you have found all of the fauna on a planet, be sure to upload the completed collection, using the button at the top of the page.

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The discoveries page will also give you clues about where & when to find the fauna that you still need to.

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Both the discoveries page & the analysis visor will give you extra information about the Fauna in question.