In Latin, otis, as a stand-alone noun, is the name of a sea bird.  However,
the suffix -otis, as used in molluscan names, is usually derived from the
Greek otos, meaning ear - as in Haliotis; Stomatia phymotis; Lampadion otis.
(The aperture of this last named species really does look like an ear!)  The
prefix oto- means the same thing, as in Otopleura.
Paul M.