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Re: Platypuses may be older than we think...
But I really wish people (in the video, too!) would stop talking about
"reptiles". The bifurcated thingie is unique to squamates (or lepidosaurs?)
and not found in crocodiles or turtles (or of course birds). It is clearly
not the plesiomorphic condition for sauropsids or amniotes.
BTW, this is not the only instance of such a completely invalid
generalization. Remember how in "reptiles" the jaw joint is formed by the
quadrate in the upper and the articular in the lower jaw? I always thought
it was highly unusual that in the near-mammal *Probainognathus* the
surangular participated in the joint (on the lower-jaw side), and this
condition has been portrayed as leading to participation of the dentary in
the jaw joint. Nonsense. The surangular making up the medial 1/3 of the
joint surface is the normal condition throughout limbed vertebrates at
least, and the lepidosaurs are almost unique in having lost that.