A question on article usage/omission

[Cifi]

... and probably not the last one

In a Duolingo sentence similar to "no dijo que había ratones pero sí mencionó las hormigas", I understand that ratones can't have a definite article (because it isn't used with haber), but what about las hormigas? Would it work without: "... pero sí mencionó hormigas"?

I take it for what Butt & Benjamin call a partitive noun, referring to some (unspecific) ants rather be than to all ants in general (as in "odio las hormigas"). Am I wrong here? Or is it specific, like "exactly these ants here"?

[Fer²]

As I see it, these are specific ants. You've got to the place in question and found both mice and ants. They had mentioned the ants [the ones that are there], but said nothing about there being any mice [at all]. You could also say «... sí que mencionó hormigas», no article, if you've had no confirmation yet about any ants.

[Cifi]

This was my suspicion, too. Then this probably should have been translated to "but she did mention the ants" instead of "she did mention ants", shouldn't it?