[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
(Fwd) Re: LATE SURVIVING CYNODONT
Here is an answer that I wouldn't withold from you.
It comes from Martin Jehle, who was subscribed to the dinosaur list for a while,
and who is rather familiar with early mammals.
------- Forwarded Message Follows -------
From: "Martin Jehle" <firstname.lastname@example.org>
Organization: Universitaet Regensburg
Date: Mon, 9 Jun 1997 08:16:12 +0200
Subject: Re: LATE SURVIVING CYNODONT
I suppose that if a living Cynodont was found, the
discussion whether it was already a mammal would still continue after
its dissection. As far as I know, the jawbone articulation is no
longer generally regarded as the single criterium for distinguishing
between mammal-like reptiles and mammals. The border between the two
groups is drawn by each author according to his personal preferences.
Authors have even named clades like Mammaliaformes which express that
some forms are in a transitional state and cannot yet be classified
as "true" mammals (Mammalia), but are very closely related to them.
In addition, it cannot be excluded that the final condition of the
jawbone articulation as we find it in mammals evolved independently
in several lineages (even if all extant mammals may belong to one of
those clades). If Mammalia were defined by the condition of their
jawbone articulation, all of those independant lineages were mammals
by definition, but their common ancestor would still be a mammal-like