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Re: Viva Marsupialia!
>> It also may be a mistake to assume that placentals have a superior
>> reproductive strategy just because they are more succesful than
>> marsupials nowadays. Marsupials held thier own against placentals
>> through most of the Cenozoic.
>In Australia, marsupials not only held their own in the Cenozoic, but
>may even have triumphed over the placentals. A tooth from the early
>Tertiary of northeastern Australia (named _Tingamurra_) seems to
>come from a condylarth. (The Condylarthra is a paraphyletic group of
>placentals that is believed to have given rise to the whales and all
>ungulate groups.) Placentals (least of all condylarths) weren't
>supposed to be in Australia until the arrival of rats and bats in the
We have to be careful about this comforting piece of dogma. Remember that
fully one half of the native Australian mammals are placentals, those being
roughly equal numbers of bats and rodents. I am not too sure that a single
tooth of _Tingamurra_ really buttrusses the argument all that much.