RE: Segnosaurs ejected from AVES

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Filippo Calzolari wrote: 


>Furthermore, the problem here , with what Ken has written, has really
>little (if anything at all) to do with the particular  SLC issue; if you
>didn't get that, we were talking about approaches to a certain kind of
>problems...kind of a theoretical discussion.

Couldn't have said it better myself.  The thrust of the discussion concerns
the utility of apomorphy-based definitions in general.  Ken advanced the
semilunate carpal as a "key apomorphy" to hang the clade Aves upon, and
myself (and others) have being trying to point out the weaknesses (potential
and actual) of Ken's approach.  This has enormous repercussions for Taxonomy
and Systematics, way beyond the the carpal configuration of basal
therizinosaurs.


>to keep on saying that Beipiaosaurus has indeed a SLC, but anybody >willing
to show that the contrary is true....you gotta look at the >specimen for
other things, I think, otherwise we should always be >looking at them and
nobody(here in the list) would actually be able to >discuss about anything,
unless you're ready to buy  tickets to china to >every DML member willing to
discuss therizinosaurs' wrist morphology. 

Yep, if somebody is going to *exclude* a group of taxa from a group because
you don't agree with the interpretations of a scientific study, the onus is
on that persony to disprove that study by looking at the original specimen.


Scientific descriptions of specimens are published so that people who
haven't seen the original material can gain an insight into the specimens.
Sure, they're not necessarily the final word on a given specimen (the
original description of _Sinosauropteryx_ is a good example); but nor should
anyone wishing to comment on or ask questions about a specimen be required
to re-describe the specimen themselves.  That seems like a horrible waste of
time to me.

Like Tracy, I'm also aware of the dangers of naming and re-describing
specimens on the basis of figures alone (published or unpublished).  There
are several dinosaur genera that have been named "sight unseen" (e.g.
_Jainosaurus_, _Jenghizkhan_) and I'm not certain that these new genera have
really helped in elucidating the taxonomic status of the relevant specimens.

 


Tim