Someone asked me recently about the conjugation of the obscene verb futuō, futuere, futuī, futūtus—and in particular about the quantity of the ū in the participle.
I intended to look at some other -uō verbs to compare them, but realized I couldn't think of any others off the top of my head. The only one that came to mind was renuō, which is intransitive and doesn't have a passive participle. (L&S don't list a future participle either, which I'm taking to mean that form is unattested.)
Are there other verbs in -uō? And if so, do they have participles in -ūtus? (Intransitive verbs with participles in -ūturus are also welcome!)