Tim Williams wrote:
> I also think it's a great idea to have a clade beginning with Eu- or
Neo- to
> be inside the corresponding more-inclusive clade, especially given the
> situation regarding certain dinosaur clades. For example, Ornithopoda
> (node-based) is defined to include _Heterodontosaurus_ but to exclude
> _Triceratops_. Thus, if heterodontosaurids are closer to ceratopsians
than
> to euronithopods, then Ornithopoda is invalid, but Euornithopoda
> (stem-based) would continue. This is very silly.
I would disagree strongly in the case of 'Eu-'. This prefix (meaning
'true', as most listmembers are probably aware) has been widely used in
multiple circumstances in nomenclature. The first circumstance, as in
Eusauropoda, could probably be interpreted as defining 'what everyone
thinks of as a [sauropod, in this examples], excluding weirdo basal
forms'. Euornithopoda (and Eutriconodonta) probably represent a slightly
different sense, where a larger taxon has turned out to be
para/polyphyletic, but a significant portion still forms a monophyletic
core.