[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Kileskus and Proceratosauridae
On Wed, Mar 31, 2010 at 4:18 AM, Jaime Headden <firstname.lastname@example.org> wrote:
> Â Unfortunately, the idea that a "clade" is the general product of a
> cladistic analysis, or is any grouping to be found on a tree, is common at
> least in the lay media.Â I do not have a specific citation.Â I do not aver
> that this is an authentic use of the term, but that it has been used as such.Â
> This is, again, replicated in the lay media, who did not themselves make
> this out of whole cloth.Â As far back as at beginning of the use of
> cladistics in the discussion on this very mailing list, at least, the term
> "clade" was being used as a form of "uppity" expression equivalent to
> "group."Â A "paraphyletic clade" and a "paraphyletic group" and a
> "paraphyletic grade" were essentially the same things, depending on who was
> using them.
> Â As a special note, even our own Mike Keesey has used the term, which I've
> dug up here: http://dml.cmnh.org/2001Dec/msg00054.html
No, that's me quoting Rob Schenck. "Paraphyletic clade" is an oxymoron
-- there is no such thing, any more than there are square planets or
> Â I've also become somewhat confused, as I was aware that the recent shift
> for absolute definitive understanding to the term "clade" is abruptly recent;
> I am not familiar with a concrete definition for "clade" in many of at
> introductory texts on the matter that I've read, although I've not read some
> of the more recent ones
"Clade" has always referred to "an ancestor and all of its descendants".
In my 2007 paper <http://dx.doi.org/10.1111/j.1463-6409.2007.00302.x>,
I discussed the question of what comprises an "ancestor". To account
for cases where organisms have multiple parents, I found it necessary
to coin a new term, "cladogenetic set", for a taxon having these
1. No member is ancestral to any other member.
2. All members share at least one common successor.
"Successor" = "descendant or self", so all singleton taxa would be
cladogenetic sets. Another example of a cladogenetic set would be two
parents who have one or more children together. Larger sets may be
cladogenetic as well.
Subsequently I shortened the term to "cladogen" and changed "member"
to "subunit", so that it would be applicable at various levels of
resolution (species, population, individual, etc.) This is in a
specification that is still being worked on, here:
So, to arrive at the point, more specifically, a clade would be the
union of a cladogen and all successors of all subunits of that
> Â What was the original useage of the term "clade?" I would follow that up
> with who defined the term, and where it was defined? These things would be
> interesting from an historical point.
Julian Huxley coined the term in 1957. I don't have access, but the
paper is here if anyone wants to check:
T. Michael Keesey
Technical Consultant and Developer, Internet Technologies