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>]

Anthony <keenir@hotmail.com> wrote:

> Then what's the problem?  the -oidea and such would be a legacy of its past,
> and would be less noteworthy than that we English-speakers say we wear shoes
> and not shoen  (its the same thing - just in two early modern dialects)

I thought the problem was clear - it was spelled out in Matt's post.
The ICZN and phylogenetic nomenclature (PN) have different rules
regarding how to treat certain taxa (coordinated family-level taxa -
such as families and superfamilies).

In the eyes of the ICZN, the -oidea of Tyrannosauroidea designates it
as a 'superfamily'.  As such, it is linked to Tyrannosauridae, which
the ICZN regards as a 'family'.  Both Tyranosauridae and
Tyrannosauroidea therefore fall under the jurisdiction of the ICZN,
and must conform to rules regarding priority.  A strict application of
ICZN rules would say that Tyrannosauridae should be replaced by
Deinodontidae - because both _Tyrannosaurus_ and _Deinodon_ belong in
the same family, and Deinodontidae was named first.  As an extension
of this, Deinodontoidea would replace Tyrannosauroidea, under ICZN
rules.  I think this approach is a bad idea.

Under PN, on the other hand, Tyranosauridae and Tyrannosauroidea are
defined as clades.  Being a 'family' and 'superfamily' makes no
difference at all - they are treated the same as any other clade.
Deinodontidae and Deinodontoidea are not defined as clades, so they
have no standing under PN.  They do not exist.  This is fine by me.


> if Coeluroidea gets defined next week or next year, it has priority over the
> older definition of Tyrannosauridea?  even if that's true (and not an
> understandable misinterpretation or misreading), wouldn't that only matter
> if Coeluroidea is given the exact same definition of Tyrannosauridea?

It doesn't matter to ICZN.  According to ICZN, a family (or
superfamily) doesn't need a definition in order to be valid.

This is how ICZN rules regarding families (-idae) and superfamilies
(-oidea) complicate things in PN.  PN says a clade needs a definition
in order to be valid.  The ICZN only looks at which family was *named*
first.  It doesn't care about phylogenetic definitions.

(In its defense, the ICZN Code was crafted in the epoch of Linnaean
ranks, long before PN came on to the scene.  But now it's time to move
on, and abandon the ICZN's role in the naming of families etc.  The
ICZN can stick to genera and species.)