[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Defining Ornithischia (was Re:)
David Marjanovic writes:
> > Mr. Peters is using a character-based definition for
> > Paranornithischia. For example, Mr. Peters regards
> > the following characters as important in establishing
> > a relationship between Lotosaurus, Silesaurus and
> > Lesothosaurus:
> > 1. Ventral maxilla is narrow.
> > 2. The orbit marks the halfway point of the skull.
> > 3. The quadrate rises vertically and is concave
> > posteriorly.
> That is not a definition. It is a diagnosis. A definition would
> have to mention at least one organism.
A phylogenetic definition would have to mention at least one organism,
yes; but there are other kinds of definitions, and for most of the
last 249 years, "key character"-based definitions were almost
Don't get me wrong, I think phylogenetic definitions are definitely
the way to go; but to say that any other definition is not a
definition is revisionism.
Anyway, there's nothing to stop me defining Interestingdinosauria as
all members of Dinosauria that massed more than 10,000 kg.
/o ) \/ Mike Taylor <firstname.lastname@example.org> http://www.miketaylor.org.uk
)_v__/\ "In the late 40s, it was felt by some academics that Britain
would need three or four computers, and the US six or seven.
Unbelievable but true. Those early computer pioneers certainly
were morons" -- Andrew Brand.