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Re: Battat's hair; Prototheria



>>Monotreme mommas make milk--how can they
>>not be mammals?
>
>   As I understand it, they (spiny anteaters, echindas, and platypuses) don't
>have a special gland in one spot on their bodies such as a mammary gland, but
>rather they "sweat" a milk-like equivalent out of tiny gland spread all over
>their bodies like pores (which the babies lap up rather than nurse).
>   No breasts=not a mammal
>   Now how would you prove therapsids did it one way or another?

Monotremes have mammary glands and very small nipples. The gland is quite
large in lactating females, and runs below the skin from the chest down.
The size of the gland depends on whether the mother has suckling young.
Females without young have very small mammary glands. The first female
examined was a non-lactating one, this and the very small size of the
nipples gave rise to the notion that the monotremes did not posses mammary
glands. This is know known to be incorrect (see for instance Griffiths
1978).

Chris

Griffiths, M. (1978) The Biology of the Monotremes", Academic Press, New York


cnedin@geology.adelaide.edu.au,   nedin@ediacara.org
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Many say it was a mistake to come down from the trees, some say
the move out of the oceans was a bad idea. Me, I say the stiffening
of the notochord in the Cambrian was where it all went wrong,
it was all downhill from there.