[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
RE: Defining Ornithischia (was Re:)
Guy Leahy wrote:
Some authors would further expand/subdivide Ornithischia.
When you say "some authors", do you mean "one author"?
For example, in two issues of the popular magazine Prehistoric Times
(Issues # 80 and # 81:
David Peters has written articles where he groups *Lotosaurus*, *Effigia*,
*Sacisaurus* and *Silesaurus*together as a subclade within Ornithischia.
Mr. Peters coins the term "Paraornithischia"
for this subclade. Mr. Peters defines "Paraornithischia" as ornithischians
which possess a predentary bone, but do not have retroverted pubes.
With all due respect to David Peters... this is rubbish. OK, so I guess I'm
stretching the obligatory "with all due respect" to breaking point, but here
First of all, it is very difficult to take Mr Peters' phylogenies seriously,
given his (a) lack of understanding of cladistic methodology in general; (b)
lack of understanding of character coding in particular; (c) use of
imaginary characters obtained by Adobe Photoshop. Give a computer with PAUP
to a tree full of monkeys and they would probably produce the same phylogeny
as Mr Peters.
Secondly, it sounds like Mr Peters is using a character-based definition for
Paraornithischia. However, from your description of "Paraornithischia" it
appears that this group is paraphyletic, and therefore not a clade. I'm not
certain that Mr Peters is aware of the difference.
Thirdly, I would not look to "Prehistoric Times" for the latest
ornithischian phylogeny. I would defer to the scientific literature,
This is not a criticism of Guy Leahy (it was an honest and well-intentioned
posting) or of Prehistoric Times. It's merely an attempt on my part to
bring ornithischian phylogeny back to reality.
Get a FREE small business Web site and more from Microsoft® Office Live!