doubtful rodent paraphyly

[Gurcharan Singh]

I think the size of the group is not that important. The primary situation
qualifying the group to be called as paraphyletic is "the group does not
include all the descendents of the most recent common ancestor". There are
two solutions. One as I suggested earlier locate the excluded descendents
and and include it within the group to make it monophyletic (or call it
holophyletic). The other solution is to locate within the group members
which are cladistically related to the excluded descendents and merge them
with the latter. We will again be left with two groups, but both now
monophyletic: One truncated original group which is no longer paraphyletic
and second group formed by the merger of originally excluded descendents and
those which have now been taken out of the originally paraphyletic group.
  I being a botanist am not well versed with Rodentia, but the concepts of
phylogeny are same whether we are talking about animals or plants. If
Lagomorpha are indeed the excluded descendents merge them in Rodentia , or
else take out the members of Rodentia which make it paraphyletic and merge
these with Lagomorpha ( choosing the rank or name you like but of the same
rank as truncated Rodentia.
-----Original Message-----
From: Ken Kinman <kinman at HOTMAIL.COM>
To: <TAXACOM at USOBI.ORG>
Date: 17 October, 1999 8:59 PM
Subject: doubtful rodent paraphyly


>     The goal is indeed to find if there are any "excluded descendants" (as
>Dr. Singh alluded to).  However, just simply including these descendants in
>Rodentia is only a viable option if the excluded group is relatively small
>(e.g., a family of insectivores, or a small order such as the aardvark).
>     If the excluded group were a medium-sized taxon, such as Lagomorpha
>(which seems to me the most likely scenario for rodent paraphyly, if it is