Sorry, it isn't in my data base.
And it is possible that Annis is a surname, but it's more commonly a first name.
It is sometimes spelled Annice.
I can't find her, though, in the ancestry.com records, except in the web trees with no sources, AND no clear stating of first or last name.
Given all this, I myself would put Annus in the first name field, and hold myself in waiting for any new information!