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PSITTACOSAURIDS AND VARANUS



Darren "I've got an office now" Naish wrote:
<<If we were to reassign varanids to subgenera (and assuming we wanted 
to keep all our taxa monophyletic), we would end up with a wealth of 
subgenera - I mean 15 or 20 as opposed to 5 or 6. It is therefore 
being advocated at present that division of _Varanus_ into subgenera 
is unwarranted or, at best, unwise.>>

Perhaps, perhaps not.  There is no real need to name a new genus for every
single species of _Varanus_.  Simply perform a cladistic analysis and find
some well defined clades and name stem based genera, like 5 or 6, rather than
15 or 20.

In an ideal world, the genus _Psittacosaurus_ would be split into 5 genera.
Here is a cladogram of how I see the specific interrelationships of the
psittacosaurids:

+--+--Psittacosaurus mongoliensis
|  |--P. sattoyaraki
|  +--+--P meileyengensis
|     +--+--P. ordosensis
|        +--+--+--P. sinensis
|           |  +--P. xinjiangensis
|           +--+--P youngi
|              +--P neimongoliensis
+--NEOCERATOPIA

_Psittacosaurus mongoliensis_ would be the only species to remain in that
genus as it forms a sister clade to all other psittacosaurids.  The stem {P
youngi > P sinensis} should be a new genus, as should the oposing clade.  P
ordosensis, and P meileyengensis should be given new generic names since they
represent "paraphyletic" outgroups to the {sinensis + youngi} node.
Psittacosaurus sattoyarraki is only part of a dentary that simply shows it
doesn't fall within the {sinensis + youngi} node.

So yes, back to the point, something like this could be done with _Varanus_
with a minimum of headaches.

Peter Buchholz
Tetanurae@aol.com

One day I didn't eat for four days