Interesting. You're right, it is not capitalized in the original article. Although i still think the passage you are quoting is talking about normal text and not title case.

Which is kind of confusing to me as when i tried to look it up in style guides, they seem to indicate that all nouns should be capitalized in a title, e.g. https://apastyle.apa.org/style-grammar-guidelines/capitaliza...

There is this [1]. Maybe it applies here

> When an animal name is part of a journal article title, it is conventional to provide the animal’s scientific name (genus and species). Genus is always capitalized and species is not. Notice that the scientific names are also italicized

[1] https://blog.apastyle.org/apastyle/2017/02/-how-to-format-sc...