Mammalia sister of Reptilia? (how cladists shot themselves in the foot)
kinman at HOTMAIL.COM
Mon Mar 13 19:41:06 CST 2000
James et al.,
I know exactly what you mean. The strict cladists do make things very
Many of them have attempted to create a monophyletic Reptilia by adding
the birds, and shifting the pelycosaurs and therapsids to the Mammalia, and
as I noted earlier the mesosaurs may well throw a wrench into that solution
(i.e., not just silly, but downright erroneous).
The rest of the strict cladists have abandoned this broadly-defined
Mammalia, and they defined a strictly delimited "crown group" Mammalia
(common ancestor of monotremes and therians, and all descendants). The big
problem with this other cladistic solution is that it is cladistic
"anchored" to monotremes, and they have a miserably poor fossil record.
Therefore a crown clade Mammalia wasn't a very good idea either.
The common sense approach I take (in the Kinman System), takes a
traditional paraphyletic Reptilia, and places two Kinman markers within that
classification to show where Mammalia and Aves would appear in a cladistic
classification. This renders the Reptilia informationally complete
My definition of Mammalia is the traditional character-based one (the
three bones in the ear), rather than the cladistically defined
(nominalistic) attempts referred to above. My traditional Mammalia is
slightly more inclusive than the "crown group" Mammalia, but it is based on
a very solid character rather than nominalistically anchoring it to
monotreme ancestors (of which we know very little because there is almost no
In my opinion, the strict cladists really "shot themselves in the foot"
on this one, fighting over two very different definitions of Mammalia, both
of which were poorly conceived. The traditional Mammalia just keeps looking
better and better. They can call me an essentialist if they want to, but it
certainly beats being a confused nominalistic cladist. I use cladistic
analysis, but certainly not strictly cladistic classification (Ernst Mayr
call the latter "cladification").
>From: "DR. JAMES ADAMS" <JADAMS at EM.DALTONSTATE.EDU>
>Reply-To: "DR. JAMES ADAMS" <JADAMS at EM.DALTONSTATE.EDU>
>To: TAXACOM at USOBI.ORG
>Subject: Re: Mammalia sister of Reptilia?
>Date: Mon, 13 Mar 2000 12:55:54 -0500
> I know that we were talking about grammar, but the statement
>itself bothers me. How can a clearly paraphyletic group (like the
>reptiles) that to be monophyletic would *include* the mammals be
>the *sister* to anything? The sister would be the closest
>*monophyletic* lineage within the reptiles to the mammals, not the
>reptiles as a whole.
> Just my two cents worth. Sorry if someone else has already
>pointed this out!
>Dr. James K. Adams
>Dept. of Natural Science and Math
>Dalton State College
>213 N. College Drive
>Dalton, GA 30720
>Phone: (706)272-4427; fax: (706)272-2533
>U of Michigan's President James Angell's
> Secret of Success: "Grow antennae, not horns"
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