I miss the definition of ammonite. In my opinion, many authors confuse the term "Ammonite" and "Ammonoid". Ammonoids (Ammonoidea) are large group of cephalopods including for example goniatites (Goniatitida), ceratites (Ceratitida) and ammonites (Ammonitida?).
But what do we call "true ammonite"? Is it an ammonoid with ammonitic suture? This way, many triassic, jurassic, creataceous and possibly paleogenic (danian) ammonoids could be called true ammonites, because they have complex (ammonitic) sutures.
Can you show me where ammonites are on phylogenetic tree? Can we call phylloceratina, psiloceratina, lytoceratina, ammonitina, haploceratina, perisphinctina and ancyloceratina ammonites? Can we call phylloceratina, psiloceratina, lytoceratina ammonoids, but not ammonites?