Quote:
Originally Posted by JohnD
The Wiki does not reflect the continuing dispute among taxonomists as the status of the monotremes - class (equal to mammalia) or order (sub-classification of mammalia. Previously classification depended on detailed examination of anatomy.
Modern classification uses biochemistry and genetics. Did you read the second link, or where the abstract says "Phylogenetic analysis of the protamine P1 gene sequences indicates that the monotremes occupy a position half-way between the eutherian mammals and birds. From the DNA sequences we estimate the time of divergence of the platypus and the echidna to be around 22 million years ago. This date agrees very well with the published estimates of divergence based on other criteria."
See also: http://genomebiology.com/2005/6/5/218
John |
And they seem to go back well over 100 Million years. Long before the Dinosaur extinctions.
I wonder how Dolphins would compare to the differences between mammals and monotremes?
But that's a side issue. I tend to think of Monotremes as mammalian, but not necessarily mammal.
It's a Key point of evolution. And the problems that can arise in classification of such changing diversity
