RE: mammalian lineages (was Re: Cretaceous taeniodont)

["Tim Williams" <twilliams_alpha@hotmail.com>]

Eric Martichuski wrote:

> I guess I'm just having trouble wrapping my brain around the idea of 
> mammals that aren't placental _or_ marsupial (or monotreme).  What else is 
> could there be? ;-)

There are lots and lots and lots of extinct mammal species that do not fit 
inside Monotremata or Marsupialia or Placentalia.  Some can be placed close 
to one of these clades, but many cannot (e.g., docodonts, gondwanatheres, 
multituberculates, spalacotheres, triconodonts, etc etc).  To further 
complicate things, there are different different definitions of 'Mammalia' 
(as opposed to Mammaliaformes or Theriiformes, for example).  Frankly, 
mammal phylogeny makes my head spin.

BTW, I just found out that there's a Late Triassic mammal named _Mojo_!  
(_Mojo usuratus_ to give the full name.)


Tim

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