RE: Definitions

["T. Michael Keesey" <mightyodinn@yahoo.com>]

--- Steven Mahon <floridamahon@yahoo.com> wrote:
> --- "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu> wrote:
> > Dinosauria is _Triceratops_, Aves, their most recent
> > common ancestor, and
> > all of its descendants (Padian and May, followed by
> > Sereno 1997; however, a
> > second school holds a definition _Iguanodon_,
> > _Megalosaurus_, their most
> > recent common ancestor, and all of its descendants).
> 
> What do you mean by second school?

The draft PhyloCode actually explicitly recommends this definition:

"Recommendation 11A. Definitions of converted clade names should be stated in a
way that attempts to capture the spirit of historical use to the degree that it
is consistent with the contemporary concept of monophyly. Consequently, they
should not necessitate, though they may allow, the inclusion of subtaxa that
were historically excluded from the taxon. To accomplish this goal, internal
specifiers of converted clade names should be chosen from among the set of taxa
that were considered to form part of a taxon under either the original or
traditional ideas about the composition of that taxon, and they should not
include members of subtaxa that were not historically considered part of the
taxon.

"Example 1: The name _Dinosauria_ was coined by Owen for the taxa
_Megalosaurus_, _Iguanodon_, and _Hylaeosaurus_, and traditionally the taxon
designated by that name has included these and certain other non-volant
reptiles. It has not traditionally included birds. Although birds are now
considered part of the dinosaur clade, the name _Dinosauria_ should not be
defined using any bird species as internal specifiers. Such a definition would
force birds to be dinosaurs, thus trivializing the question of whether birds
are dinosaurs. Instead, internal specifiers should be chosen from among taxa
that have traditionally been considered dinosaurs; e.g., _Megalosaurus
bucklandi_ von Meyer 1832, _Iguanodon anglicus_ Holl 1829, and _Hylaeosaurus
armatus_ Mantell 1833."

(I would point out that _Iguanodon bernissartensis_ has been designated by the
ICZN as the type species for _Iguanodon_, and might make a better specifier.)

[Sauropodomorpha] 
> I thought it was Saltasaurus > Aves? Is there
> something I'm missing?!
 
Sounds like an old-Dinosauricon-generated error.

> I also had heard that there might be a Dinosauria
> definition that includes Herrerasaurus. Does it really
> exist?

"Dinosauria would comprise Herrerasauridae, Saurischia, Ornithischia, the
common ancestor of the aforementioned taxa, and all its descendants."

Novas, F.E. 1992. La evolución de los dinosaurios carnívoros. in Los
dinosaurios y su entorno biotico. Actas II Curso de Paleontologíca en Cuenca.
pp. 125-163.
 
> Also, I don't think I should have make a page for
> every taxon. What main clades *should* I make pages of
> that would represent the major clades well?

I did this on the old Dinosauricon (http://dinosaur.umbc.edu). Really, it's a
matter of taste.

=====
=====> T. Michael Keesey <keesey@bigfoot.com>
=====> The Dinosauricon <http://dinosauricon.com>
=====> BloodySteak <http://bloodysteak.com>
=====> Instant Messenger <Ric Blayze>
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