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RE: Weird mammal cladograms, and dino implications



 

I'm glad Tony brought up Tom Rich's latest mammal paper, it contains an
interesting titbit that makes some sense in the light of this new mammal
phylogenetic work. Tom Holtz said that Hedgehogs come out as the basal to
all other placentals. Tom Rich noted that Ausktribosphenos nyktos was
strikingly similar to hedgehogs. Indeed if A. nyktos had been found in later
Neogene sediments from the Northern Hemisphere it probably would have been
called a hedgehog. When I first read this I thought that must have
represented convergence since Hedgehogs were deeply nested within the
placentals and it doesn't make sense to find one in the Lower K of
Australia. Now I'm not so sure. Anyway food for thought.
For those of you who might have trouble getting Records of the Queen
Victoria Museum, Rich is proposing that various small microplates such as
the West Burma Microplate, which split off of Australia sometime in the
Early Creataceous, carried a Noahs Ark of animals from Australia to Asia
(where the microplates accreted). As well as placental mammals Rich suggests
that ancestral ankylosaurids, neoceratopsians, oviraptorids and
ornithomimids might have got into Laurasia this way as well (if the
admitedly scrappy remains from Flat Rocks has been correctly identified). 

cheers

Adam