Re: Addendum (Re: LATE SURVIVING CYNODONT)

[Pieter.Depuydt@rug.ac.be]

> From:          Dinogeorge@aol.com
> Date:          Tue, 10 Jun 1997 15:26:18 -0400 (EDT)
> To:            Pieter.Depuydt@rug.ac.be, dinosaur@usc.edu, 
> radass@orion.neca.com
> Subject:       Re: Addendum (Re: LATE SURVIVING CYNODONT)

> In a message dated 97-06-10 14:41:32 EDT, Pieter.Depuydt@rug.ac.be writes:
> 
> << platypus and the marsupials shear a more recent 
>  common ancestor than each with placental mammals. >>
> 
> So egg-laying was lost >twice< in Mammalia, once above platypus in
> platypus+marsupial clade, and once more (convergently) in placental clade?
> And--marsupial birth mode is not a stage in the evolution of the placental
> birth mode?

Things seem indeed to get turned upside down a bit; do we meet a 
reversal again?
In the same Nature 'News and Views' the authors refer to a 1947 
publication of Gregory, who already supported marsupial/monotreme 
near relationships on a number of morphological similarities.
Gregory explained the monotreme reproductive system as a 'neotenuous 
stage of development that was transient in some marsupials'
(Gregory, Am Mus Nat Hist Bull 88, 1947).

Pieter Depuydt