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Re: Generic and specific variation (incomplete)



>>Frankly, I believe the multi-genera thing is not the way to go.

>Since Linnean ranks are not natural groupings in and of themselves, 
>what difference does it make?

Actually, the Linnean system in the form we are now using it as is, is 
becoming more and more degrading as it builds up its subclades, 
paraclades, parvi's, super's, eu's, and the like. My belief falls under 
the grouping of ancestor-to-descendant characterizing (i.e. 
*Struthiomimus* and *Ornithomimus* are brothers, and *Dromeciomimus* is 
a nephew, one step down on the ladder).

[other ornithomimids]
 |
 *Struthiomimus*
 |           |
 |          *Dromeciomimus*
 |
 *Ornithomimus*

That is a cladistic phylogenetic list for these three genera, which Paul 
placed into the one genus *Ornithomimus* all the rest being specific 
branches off of. I do not know of any other study made of all the 
Ornithomimidae, except for Paul's, which did not include *Anserimimus* 
or *Pelecanimimus*. So I count his as an authoritive study, as well as 
the info I can get from Mike Keesey's website, a great collection of 
clades for myself, and one that has helped me in the past.

The Linneistic approach, which I disagree with for its of-late abuse and 
original unusefulness, is to clump every succesive character into a new 
name, and assign that name a phyllogenetic place above others (e.g. 
Ankylopollexia, for *Dryosaurus* plus *Camptosaurus* and all of his 
descendants). Why characters can't stand alone, I don't know, but the 
need to call something something is such a human character in and of 
itself. So the Ornithschia now has a big messy naming system which 
really turned me off.

The monophylletic approach for the Ornithomimidae is thus:

Ornithomimidae
|  
|--*Pelecanimimus*
|
|--*Harpymimus*
|
|--*Garudamimus*
|
|--*Archaeornithomimus*
|
|--*Anserimimus*
|
|--*Struthiomimus*
|   |
|  *Dromeciomimus*
|
|--*Ornithomimus*

The linnean approach is thus:

ORNITHOMIMIDAE
|  
PELECANIMIMINAE
|
|--*Pelecanimimus*
|
|--*Harpymimus*
|     
|--*Garudamimus*
|
|--*Archaeornithomimus*
|
ORNITHOMIMINAE
|
|--*Anserimimus*
|
|--*Struthiomimus*
|   |
|  *Dromeciomimus*
|
|--*Ornithomimus*

But the accepted middle ground between Linnean and non-Linnean is a 
combination of both, using one where is seems to fit best, and the other 
where it does and the other doesn't. So, non for anything above a 
superfamily, and Linnean for anything below.

Jaime A. Headden

P.S. Sorry for what was originally going to be a simple answer.

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