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Re: Oh no! Not Monotremes again!
>From: email@example.com (James Shields)
> The interesting bit, however, is this:
> "Although they resemble reptiles in that they lay eggs, the monotremes are
> true mammals. They possess such distinctively mammalian characteristics such
> as mammary glands, hair, a large brain, and a complete diaphragm."
This is correct. They should also mention milk glands.
> "Most authorities beleive that the order Monotrema originated from a line of
> mammal-like reptiles different from that which gave rise to the other
This is now out of date. This seemed to be the case for awhile
in the mid '80's, but has now been shown to be based on incorrect
> No cladistics here!
Actually, the supposed evience for a seperate origin *was* based
on cladistic analysis - it just wasn't transformed into classification
by many people.
But in fact, if it had turned out to be true, even us non-cladistic
evolutionary taxonomists would have had to seperate the monotremes,
and the other non-therian mammals, from Mammalia, on the grounds that
such a Mammalia would have been *poly*phyletic, which *nobody*
accepts as valid, cladist or not.
[The main argument between cladists and non-cladists is the validity
of *para*phyletic taxa].
The peace of God be with you.