Re: Pterosaur origins

["T. Michael Keesey" <keesey@gmail.com>]

On 5/17/07, gerarus@westnet.com.au <gerarus@westnet.com.au> wrote:
> Under the ICZN rules, Coeluroidea would have priority over
> Tyrannosauroidea if one chose to recognise a superfamily uniting
> _Tyrannosaurus_ and _Coelurus_, yes. Of course, no-one is under any
> obligation to do so - you could just as easily recognise two
> superfamilies Coeluroidea and Tyrannosauroidea that happen to be
> sister taxa (though in this case, Coeluroidea would currently be
> redundant with Coeluridae). Personally, I'd probably be cautious of
> sinking Tyrannosauroidea into Coeluroidea unless the support for
> uniting them was very strong.

An excellent case of how, contrary to the perception of some,
phylogenetic nomenclature is more stable than traditional taxonomy.
Under phylogenetic nomenclature, _Tyrannosauroidea_ is defined
(http://taxonsearch.org/dev/taxon_edit.php?Action=View&tax_id=350),
while Coeluroidea has never been defined. Under ICZN rules, a basal
taxon like _Coelurus_ shifting in and out of the hypothesized clade
changes the taxon's name--under PN, there is no change.

(Incidentally, these name changes due to coordinated ranks were not an
original feature of Linnaean taxonomy.)
--
Mike Keesey