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RE: Stegosaur volume of Swiss Journal of Geosciences
Michael Mortimer <email@example.com> wrote:
> Well the postorbital horns were quite distinctive for the
> time, and even now they're almost good enough to be
> diagnostic for Ceratopsidae. It's only through historical
> accident that Ceratopsidae became a node-stem triplet clade
> that doesn't encompass things like Zuniceratops.
But how do we know that Ceratopsidae encompasses _Ceratops_?
How many phylogenetic analyses have been done recently that include
_Ceratops_? I'm guessing the answer is zero, or very close to it.
> I'd rather have rule-based taxonomy than judgement calls
> and "experience" any day. Didn't we have enough
> subjective, authority-based taxonomy in the past?
Yes we sure did. But that's not what I'm saying here. I'm simply talking
about the naming of clades.
Phylogenetic taxonomy is phylogeny-based, not authority-based. For
phylogenetic taxonomy it's my argument that family-level clades should be named
after one of the better-known (scientifically speaking) members of the clade.
Most families already are: Tyrannosauridae, Allosauridae, Neovenatoridae,
Coelophysidae, Brachiosauridae, Camarasauridae, Diplodocidae, Stegosauridae,
Ankylosauridae, Iguanodontidae, Pachycephalosauridae, Herrerasauridae, and so
But other family-level clades are named after crap genera, like Ceratopsidae
and Titanosauridae. Titanosauridae has effectively been abandoned in recent
papers, because the name-giving genus (_Titanosaurus_) is considered a nomen
dubium by most workers. Personally, I think _Titanosaurus_ is probably a valid
genus; but I also think that based on what is currently known of it,
_Titanosaurus_ is a poor choice to name a family-level clade after. So is
_Ceratops_, for the same reason; but workers still continue to use
Ceratopsidae, and I'm not sure why.
Authority and experience can be extremely important in taxonomy. For example,
when _Iguanodon bernissartensis_ was nominated to replace _I. anglicus_ as the
type species for _Iguanodon_, this choice was bas
ernissartensis_ is known from good material, and it's a model species for
I don't see why the same process can't be used to decide the names of
family-level clades, and have them all based on 'model' genera - again for the
sake of nomenclatural stability. To give one example, at the moment there is a
carnosaur clade that includes both _Metriacanthosaurus_ and _Sinraptor_. The
ICZN would say that the name of this family should be Metriacanthosauridae
rather than Sinraptoridae, because the former (as Metriacanthosaurinae) was
named first. But _Sinraptor_ is based on an almost complete skeleton, whereas
_Metriacanthosaurus_ is known only from fragmentary material. So I would say
Sinraptoridae is a better name for this clade, because it's founded upon a
well-known genus. Sinraptoridae also has the benefit of having a phylogenetic
definition, which includes _Sinraptor_ as a specifier. For the purposes of
phylogenetic taxonomy, I can see no advantage in having Sinraptoridae being
trumped by Metriacanthosauridae.
Robotically applying ICZN rules to phylogenetic nomenclature is often
downright unhelpful. It's the workers in the field of paleontology who are
best placed to decide which genera should give their names to higher clades,
not the ICZN.