David Campbell wrote,
"Another example of this issue is Nuculoidea, both a superfamily and a
(mostly?) Paleozoic genus.  I think I heard that in this case there was
someone who favored a different superfamily ending and named the genus in
part to unsuccessfully counteract the  oidea ending."

Possible, but the timing would be odd. Genus Nuculoidea was named in 1916 by
Williams & Breger. As of 1926, the Zoological Code still had no
recommendation to make on the proper suffix for superfamilies. Homonyms
among species-group names were already being rejected, but it was not until
1943 that the same principle was adopted for genus-group names (ICZN Opinion
147), and it must have been applied to family-group names even later. I
don't know when the -oidea ending was mandated -- 1999? I don't have this
edition at hand. The 1985 edition recommends, but does not require, the
-oidea ending (Recommendation 29A).

Incidentally, the 1969 "Treatise on Invertebrate Paleontology" (p. N231)
gave genus Nuculoidea a range of Ordovician to Devonian in North America,
and assigned it to superfamily Nuculacea (now also Nuculoidea as pointed out
by David). Of course, a lot has happened since 1969.

Cheers,
Andy

Andrew K. Rindsberg
Geological Survey of Alabama