[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Use of Genera



--- Mickey Mortimer <Mickey_Mortimer111@msn.com> wrote:
> T. Michael Keesey wrote-
> 
> > I have decided to place all non-neornithean dinosaurs in six genera:
> > _Iguanodon_, _Megalosaurus_, _Hylaeosaurus_, _Cetiosaurus_,
> _Plateosaurus_, and
> > _Archaeopteryx_. Expect to see binomina like _Iguanodon horridus_,
> > _Megalosaurus rex_, _Cetiosaurus excelsus_, _Archaeopteryx regalis_, etc.
> >
> > Gone will be the unproductive arguments about whether to synonymize
> > _Tarbosaurus_ and _Tyrannosaurus_, _Ornithomimus_ and _Struthiomimus_,
> etc. --
> > all _Megalosaurus_ now.
> >
> > Still got to figure out how to handle trivial homonyms (is _M. rex_ the
> > tyrannosaurid, the basal theropod, or the basal tetanuran?). Perhaps I'll
> > convert old genera (_Megalosaurus alwalkeria_, _Megalosaurus edmarka_,
> etc.)
> >
> > Working on the changes now; expect to see them in a few weeks. Any
> comments?
> 
> Unless some of your genera are paraphyletic, there's lots of species that
> won't fit into them.  Like diagnosticus Galton 1978, antiquus Morris 1843
> and nasicornis Marsh 1884.

Under the original concept, paraphyly, and even polyphyly is allowed. Stability
can only truly come from bridging to this system. Thus, _Iguanodon
diagnosticus_, _Plateosaurus antiquus_, and _Megalosaurus nasicornis_.
_Megalosaurus_ can also be extended down through the base of _Theropoda_ to the
root of _Dinosauromorpha_ (_Megalosaurus lunensis_, _M. talampayensis_, etc.)

There may be some points that could be argued about (_Hylaeosaurus lawleri_ or
_Iguanodon lawleri_? _Plateosaurus polyzelus_ or _Cetiosaurus polyzelus_?
_Archaeopteryx antirrhopus_ or _Megalosaurus antirrhopus_?), but these are
quite few in comparison to the current system, with hundreds of genera. And
once they are sorted out, stability is guaranteed.

The system can be extended to other taxa as well. All pterosauromorphs may be
labelled _Pterodactylus_, _Rhamphorhynchus_, or _Sharovipteryx_.
Crocodylotarsans need only _Ornithosuchus_, _Phytosaurus_, _Aetosaurus_,
Rauisuchus_, _Gavialis_, _Alligator_, and _Crocodylus_. (Or just make the last
three _Crocodylus_.) Basal _Archosauromorpha_ can get by with _Trilophosaurus_,
_Rhynchosaurus_, and _Prolacerta_. For the "euryapsids", _Ichthyosaurus_,
_Pliosaurus_, _Plesiosaurus_, and _Placodus_ should suffice. And so on.

> Also, it would be Archaeopteryx rex, as rex Osborn 1905 is more closely
> related to lithographica Meyer 1861 than to bucklandi Mantell 1827.

Questions of relationship are at odds with the goal of stability. If we firmly
label it _Megalosaurus_ now, there's no need to dither over what it might be
called under whose phylogeny.

And, for anyone who hasn't guessed it already (can't imagine), APRIL FOOL!

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

__________________________________________________
Do you Yahoo!?
Yahoo! Tax Center - File online, calculators, forms, and more
http://tax.yahoo.com