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



Anthony <keenir@hotmail.com> wrote:

> Were Deinodontidae and Deinodontoidea actually created, or is their
> existence assumed based on backforming from _Deinodon_ & the higher clades
> which were named for _Tyrannosaurus_?
> (I've seen backforming in linguistics, but not in nomenclature)

Deinodontidae was named by Brown (1914).  Same for Deinodontoidea.


> So, because Cope and Marsh forgot to define Deinodon's clades, we can't use
> it?  :)

We can use Deinodontidae - if we want to.  But why should we want to?
Deinodontidae is just not useful as a clade, because it's pegged to
_Deinodon_ (a nomen dubium).  Tyrannosauridae (and -oidea etc) is a
far more useful clade because it's pegged to _Tyrannosaurus_.


> Why not define it as "Tyrannosaur(__) + {insert name here}" ?
>
> for example, if the Tyrannosaurids are defined by, among other things,
> having two-fingered hands,

I'm referring to species-based definitions (e.g., Tyrannosauridae =
least inclusive clade containing _Tyrannosaurus rex_, Gorgosaurus
libratus_, and  _Albertosaurus sarcophagus_).  I don't think
character-based definitions are helpful.  Phylogenetic definitions are
best left separate to character-based diagnoses.


> let Deinodontidae/oidea be the Tyrannosaurids+the
> three-fingered species that gave rise to them.  (or was a sister species to
> the mother of the Tyrannosaurids)

That sounds like an utterly terrible idea.  I don't know why we need
these tortuously heroic measures to retain Deinodontidae.  Just let
the name go.


> So, the ICZN assumes that, if something has a name, there's no need to worry
> about finding a place for it - it  already has one?
>
> That does sound handy.

I don't understand what you're asking/saying here.


> But why stop at that half-measure?  Why not give the boot to the ICZN genera
> and species (and subspecies and superspecies and subgenera and other things
> I've heard of over the years) ?   What makes genus and species  worth
> saving, when nothing else is?

I don't think we  need to resort to this reductio ad absurdum
argument.  It's not about "saving" families.  It's an issue over
whether family-level clades should be subjected to ICZN rules
regarding nomenclatural priority (= which ones were named first),
irrespective of how and when they were first defined as clades.  ICZN
should continue to have jurisdiction over genera and species (and
subspecies, subgenera, etc).  But I don't see the sense in the ICZN
deciding the validity of familes when these same families are also
clades.  Priority and validity of *all* suprageneric clades should be
decided by phylogenetic nomenclature.