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From: winalski@psw.enet.dec.com (Paul S. Winalski)
Newsgroups: sci.bio
Subject: Platypus bones (was Re: What's a monotreme?)
Keywords: monotremes
Message-ID: <1991Apr25.182824.18628@hollie.rdg.dec.com>
Date: 25 Apr 91 18:28:24 GMT
References: <1991Apr22.111159.29888@kuhub.cc.ukans.edu> <4896@kitty.UUCP> <209@tdatirv.UUCP> <416@smds.UUCP>
Sender: news@hollie.rdg.dec.com (Mr News)
Reply-To: winalski@psw.enet.dec.com (Paul S. Winalski)
Organization: Digital Equipment Corporation
Lines: 17

In article <416@smds.UUCP>, rh@smds.UUCP (Richard Harter) writes:
|>
|>Bones.  They have mammalian jaws.  The inimitable Dr. Asimov argues in one
|>of his columns that the fusion of the relevant bones in Platypus is not
|>completed until after birth and the correct classification of Platypus
|>is a Therapsid and not a mammal at all.

I assume that you and the good Dr. Asimov mean hatching, not birth.

Reclassifying Platypus on this basis seems on the surface as silly as
arguing that human beings should be reclassified because the ductus
arteriosus and the fetal hole in the ventricular septum don't close
until after birth.

What is the common name for the Theraspids?

--PSW