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RE: tiny-armed theropods



Tim Williams wrote-

> > By that reasoning, we'd have to include Passer in the analysis too, which I 
> > don't think you'd agree
> > with.  Just as we can use our extra-analysis knowledge to be fairly certain 
> > Passer is closer to
> > e.g. Anser, Yanornis, Confuciusornis etc. than to dromaeosaurids, 
> > troodontids, oviraptorosaurs,
> > etc., we can use it to be fairly certain Troodon is closest to Zanabazar, 
> > Talos, Saurornithoides
> > and such.  There's no need to include every definition-related taxon in an 
> > analysis.
>
> This is a non sequitur. _Passer_ exists. It's a real animal - and a
> real taxon. However, if _Troodon_ becomes a nomen dubium, it is no
> longer a valid taxon. It therefore no longer represents a once
> living, breathing animal. It is *just* a name. As a nomen dubium we
> are precluded from referring any more material to it. If _Troodon_ is
> a nomen dubium then, no, I can't be certain that _Troodon_ is closest
> to _Zanabazar_, _Talos_, and _Saurornithoides_ because there is no
> such thing as _Troodon_!
>
> This separates a nomen dubium from other taxa based on poor material
> that is nevertheless diagnostic. For example, nomina dubia such as
> _Deinodon_ and _Trachodon_ are no longer relevant to discussions on
> tyrannosaur or hadrosaur phylogeny. So it's ridiculous to include
> them in a phylogenetic analysis, or (and this directly addresses your
> point) even treat them as taxa. No one talks about _Deinodon_ and
> _Trachodon_ as if they were real, distinct animals. As nomina dubia,
> they are merely names.

I don't know where you got the idea that nomina dubia aren't taxa or 
organisms.  Troodon formosus is a real animal, diagnostic holotype or not.  
There was a living organism which the type tooth of Troodon belonged to, and 
this individual can be included in a phlogenetic analysis, regardless of 
whether additional individuals could be assigned to its species.  There's no 
rule that says only taxa or only valid taxa can be included in such analyses.  
The microraptorian NGMC 91 is included by Senter (2007) for instance, despite 
being only a single individual that has not been conclusively differentiated 
from Sinornithosaurus.  Indeed, it has only been described as Dromaeosauridae 
gen. et sp. indet. and Sinornithosaurus sp. indet..

> > As I've said before on the DML, people just cherry pick from the ICZN and 
> > make up their own
> > rules, such as those involving nomina dubia.  They see their own subjective 
> > ideas of stability as
> > overruling the ICZN, and if the majority follows them, what can we do but 
> > go along with the
> > arbitrary flow?
>
> And more power to them. The ICZN should serve the community, not the
> other way round. If the ICZN rules say Deinodontidae should be used
> instead of Tyrannosauridae, I say it's the ICZN rules that are wrong.

What's the point of having a rulebook for a community if they only follow the 
rules they want to anyway?  It's like enforcing laws only when they don't 
inconvenience you.  We might as well just get rid of the ICZN if we're going to 
call it wrong when we don't like what it says.

Mickey Mortimer