Are guinea pigs really rodents?

[John Grehan]

>    There have long been suspicions and suggestions that
>Order Rodentia might be polyphyletic, and Caviomorpha seems
>to be the group most likely in need of being split off from
>rodents.  I was busy with bacteria at the time, but a few
>years ago there was some new evidence published concerning
>this issue, but I don't recall where.  Could someone
>refresh my memory about the caviomorph debate (anything on
>the internet about this?).
>                  Cheers, Ken Kinman

Perhaps of some relevance is concerns the monophyly of the "Hystricomorpha"
(or whatever might pass for this group) including cavimorphs. Simpson had
considered the group to be polyphyletic because of their occurence in the
Old and New Worlds, while Croizat identified the group as Atlantic, and
therefore monophyletic. A number of papers on morphology and genetics seem
to corroborate the monophyly. Perhaps out of date with current
developments, but some papers are cited in the panbiogeography book.

John Grehan