Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!munnari.oz.au!metro!cluster!andrewt
From: andrewt@cluster.cs.su.oz.au (Andrew Taylor)
Newsgroups: sci.bio
Subject: Re: What's a monotreme?
Keywords: monotremes
Message-ID: <2340@cluster.cs.su.oz.au>
Date: 25 Apr 91 12:55:08 GMT
References: <1991Apr22.111159.29888@kuhub.cc.ukans.edu> <4896@kitty.UUCP> <209@tdatirv.UUCP>
Organization: Dept. of Comp. Science, Uni of Sydney, Australia
Lines: 26

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.

> In fact they are mammals only in possesing milk (i.e. mammary
glands),
> insulating hair, and (to some degree) endothermy.

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.

Like the platypus echidnas have highly sensitive electro-receptors
but in the echnidna case's its not obvious what they are be used for.
Everyone interested in trivia should know the male platypus
has a venomous spur on its hind leg. Its purpose isn't certain.
One suggestion is that it is used in territorial disputes.

Andrew Taylor