Re: [dinosaur] Tyrannosaurs and Deinodons (was re New Konzhukovia species (temnospondyl) from Permian of South America + Early Triassic polar coprolites + more papers

[Tim Williams <tijawi@gmail.com>]

Matt Martyniuk <martyniuk@gmail.com> wrote:

> The confusion here comes from mixing two totally distinct nomenclatural
> systems (ICZN and phylogenetic pre-PhyloCode nomenclature).

Exactly.  Clades that end in -idae, -inae, -ini and (most of the time)
-oidea are subject to ICZN, because they are deemed to be coordinated
family-level taxa.  But, IMHO there is no need for them to be treated
as families, superfamilies, etc.  They're just clades.


> As far as the
> ICZN is concerned, neither Coeluroidea nor Tyrannosauroidea nor
> Deinodontoidea need phylogenetic definitions, let alone monophyletic ones.
> Even if Coelurus is closer to Tyrannosaurus than to Aves, Coeluroidea could
> be treated, under the ICZN, as a basal grade from which Tyrannosauroids
> evolved, or as monotypic including only Coelurus itself.  Under ICZN,
> therefore, Coeluroidea and Tyrannosauroidea are only synonyms if you want
> them to be.

However, if _Coelurus_ belongs in Tyrannosauroidea, then (according to
the ICZN) Coeluroidea becomes available for the clade that includes
both _Coleurus_ and _Tyrannosaurus_ - and Coeluroidea has
nomenclatural priority over Tyrannosauroidea (Marsh 1881 vs Osborn
1906).


> Under phylogenetic nomenclature, Coeluroidea doesn't even exist, since afaik
> it has never been defined as a clade and even if someone were to define it
> today, it would be a younger synonym, within this parallel system, of
> Tyrannosauroidea, assuming someone defined them synonymously, which  doesn't
> need to be the case (you could define Coeluroidea as a node that may end up
> as a subclade of the branch-based Tyrannosauroidea, as with Paraves and
> Eumaniraptora.

Under the current phylogenetic definition(s), Tyrannosauroidea is a
stem-based clade.  Certain phylogenetic analyses recover _Coelurus_
inside the Tyrannosauroidea (e.g., the recent _Timurlengia_ paper).
Under phylogenetic nomenclature Coeluroidea does not exist - as you
say.  But according to strict application of the ICZN rules, this
doesn't matter - Coeluroidea still has priority over Tyrannosauroidea
(because both would regarded as 'superfamilies'), irrespective of the
fact that Coeluroidea has never been defined as a clade.  This is
where the conflict lies.  Unlike Mickey, I don't think we need a
petition to the ICZN to resolve this.  I think we can simply ignore
Coeluroidea for the reason that it is not defined as a clade (whereas
Tyrannosauroidea *is* defined as a clade).


Anthony <keenir@hotmail.com> wrote:

> How is it political correctness?  (are we keeping _Tyrannosauridae_ not
> because it has priority, but because its better-known and-or is a more
> popular name?

Because it is defined as a clade, and has been used as such throughout
the literature.

> that doesn't seem any more appealing than political
> correctness.  (though, if we were being politically correct, wouldn't we
> rename it in the language of one or more of the tribes who lived where the
> type specimen of genus _Tyrannosaurus_ was found?))

Umm... what?