RE: Ceratops (was RE: Glishades ericksoni, ...)

[Jaime Headden <qi_leong@hotmail.com>]

Tim William wrote:

<But... we'll never know where _Ceratops_ sits in ceratopsian phylogeny. 
_Ceratops_ is *never* included in a phylogenetic analysis, because it is
 a nomen dubium.

I'm not saying _Ceratops_ *should* be 
included in a phylogenetic analysis; I'm only saying it *can't* be.>

Well now, that depends.

  Substantive sampling of ceratopsian crania for character is dependant on the 
researcher, and the goal, and the giants upon whose shoulder that researcher 
stands and what they did. Often this may require developing an analysis from 
scratch, and throwing previous assumptions to the wind and starting from the 
basic, philosophical argument, i.e., asking a question and then answering it. 
In this case, one should be less inclined to regard the level of material found 
as non-diagnostic and to actually test the premise by sampling the material. 
This includes not making assumptions about whether certain features are "good 
enough" to be sampled. This means you get lots of proportionate characters 
gumming up your analysios, but since we cannot know _a priori_ that a 
proportionate character is NOT useful phylogenetically, only that it _can_ be 
the product of non-phylogenetic signalling. Some regard that signalling as the 
_de facto_ mark against the character, and out it goes. I've argued this, and 
hold myself accountable for it. 

  To solve that issue, I've attempted to put together a study measuring the 
relative number of morphological features in a complex bone, the humerus, and 
restricting myself to a small clade (theropod dinosaurs). While in many cases 
I've run into issues regarding how to treat a bone with features that form 
complexes with out bones, and without having to refer to those extra bones, 
I've found that there is a good deal of variation in the theropod humerus to be 
had. Putting aside histological and microfeature aspects of the bone, and 
relative cross-sectional examination (as prone to deformation as it is), I've 
been able to discretely identifiy over 50 characters, and three times that many 
states with virtually no overlap. Should I do this for MORE complex structures, 
such as vertebral sequences, one could get into hundreds of "characters" alone. 
Are these substantive enough to proxy for phylogeny? I don't think so, and this 
is a perspective I've not been able to explore due in part to my poor education 
(I simply do not have the research capabilities, nor the tools with which to 
undertake the analysis). What I'd really like to do with this is to 
three-dimensionally model each single bone and (from a database of such things) 
complexly fit each element to one another to find discrete points of variance, 
regions of overlap, and measure these qualities, to determine the value of 
character selection to morphology. I would think that would be the future of 
comparative phylogenetics. *Ceratops montanus* could even be a front-liner for 
something as complex as the fronto-postorbital complex of ceratopsian 
braincases.

  So when we take the partial cranium with postorbital ornamentation and the 
isolated occipital condyle, we can say many things about it. Dodson DID say 
many things about it in his book, but so far, much of what could be said was 
dismissed in the greater scheme. It is hard to localize the taxon, and it is 
relatively hard to refer taxa to it. But if this specimen can be fit into a 
paraigm formed by other specimens, to the point that those specimens can be 
differentiated from others and form a "species," one could argue then that 
there is a discriminate effect of the original material, and that the effect it 
has on nomenclature is a secondary one. If, say, *Ceratops montanus* was found 
to effectively be identical in form to that of *Avaceratops lammersorum, * then 
one could consider synonymizing the two. While *Ceratops* has remained in usage 
and in doubt for most of its life, and its importance in systematics is borne 
in clades utilizing its name, we must consider relative stability, and I would 
not be loathe to supporting a case where *Ceratops montanus* was dropped in 
favor of *Avaceratops lammersorum,* or, perhaps more interestingly, the type of 
*Ceratops montanus* were transferred to that of *Avaceratops lammersorum,* 
anchoring the name, and its historical effect, on a substantive specimen. (this 
is without animosity towards either Peter Dodson or Paul Penkalski.)

Cheers,

Jaime A. Headden
The Bite Stuff (site v2)
http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)
                                          
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