Atheism is unreasonable

[Jenny A]

however an early mammal very closely related to birds and reptiles and sharing a number a characteristics with them including egg laying.

Minor quibble, Shared primitive trait, such as egg laying, does not denote close evolutionary relationship. Only shared derived trait can be an indication of closeness in relationships.

Birds and earliest mammals clearly share few true common derived traits, and those which they might superficially appear to share, like endothermy and insulating body coverings, are clearly derived separately through convergent evolution, and do not share the same derivation.

So early mammals are not closely related to birds at all. The earliest mammals are already separated from birds by 150-200 million years of independent evolution from carboniferous era (or earlier) onwards, along two widely separated evolutionary lineages. So Platypus, only ~150 million years separated from humans, is already as different from any birds as humans are from platypus.

Your right about the birds. But it is much closer to reptiles. It's the DNA from whence the traits come that matters:

World's Strangest Creature? Part Mammal, Part Reptile
Jeanna Bryner | May 06, 2008 08:00pm ET
The platypus sports a patchwork of features from mammals, reptiles and birds.
Credit: Zina Deretsky, National Science Foundation.
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The platypus sports fur like a mammal, paddles its duck feet like a bird and lays eggs in the manner of a reptile.

Nature's instruction manual for this oddball, it turns out, is just as much of a mishmash.

Researchers just mapped the genome of a female platypus from Australia. The genetic sequence of this Aussie monotreme (a type of mammal) is detailed in the May 8 issue of the journal Nature.

"The platypus is a very ancient offshoot of the mammal tree, so it was 166 million years ago that we last shared a common ancestor with platypuses," said study team member Jenny Graves, head of the Comparative Genomics Group at the Australian National University. "And that puts them somewhere between mammals and reptiles, because they still maintain quite a lot of reptilian characteristics that we’ve lost, for instance they still lay eggs."

She added, "So we can use them to trace the changes that have occurred as we went from being a reptile, to having fur to making milk to having live-born young."

http://www.livescience.com/7488-world-st...ptile.html