Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!tdatirv!sarima
From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: sci.bio
Subject: Re: What's a monotreme?
Keywords: monotremes
Message-ID: <217@tdatirv.UUCP>
Date: 26 Apr 91 20:36:22 GMT
References: <1991Apr22.111159.29888@kuhub.cc.ukans.edu> <4896@kitty.UUCP> <209@tdatirv.UUCP> <2340@cluster.cs.su.oz.au>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 34

In article <2340@cluster.cs.su.oz.au> andrewt@cluster.cs.su.oz.au (Andrew Taylor) writes:
>In article <209@tdatirv.UUCP>, sarima@tdatirv.UUCP (Stanley Friesen) writes:
>> There is essentially no fossil record of monotremes.
>
>The have been 3 fossil platypus finds in the last 10 years in
>Australia.  The oldest is the 110 million year old opalised jaw of
>Steropodon galmani from Lightning Ridge. It was much larger than the
>present day platypus.  The location was within the Antartic circle then
>and the annual average temperature would have been 5C.

Jehosephat!!  I am getting behind on my mammalian fossils!
[I have been concentrating on dinosaurs].
I had heard (vaguely) about some sub-recent (Plio-Pliestecene) monotremes,
But a mid-Cretaceous platypus I had *not* heard of!
(BTW are you *sure* of that date, I would have thought that would be such
a major find I would have heard of it).
[Not that such an early momotreme is all that unexpected, given the apparent
relationships].

>Views on the thermo-regulation of Echidnas are changing. Its recently been
>found that they hibernate. This allows them over-winter in the high country
>of the Australia Alps.  They have been accused of primitive-thermoregulation
>and incomplete homeothermy. Instead their thermoregulation may be
>highly specialised.

Quite true, controlled temperature reduction in winter could well be a
specialization rather than a primitive trait.

I suspect this requires more research.  Thermoregulation is still poorly
understood in many ways.  Certainly there is no really good 'classification'
of differing modes of thermoregulation.
-- 
---------------
uunet!tdatirv!sarima				(Stanley Friesen)