Assertion: necked plesiosaur | /r/HasProperty | polyphyletic
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Source sentences:
text: Although long-necked plesiosaurs (the traditional sub order Plesiosauroidea) may be polyphyletic (and I think the jury is out on this), I don't think that anyone has suggested that the elasmosaurs (i.e. = Elasmosauridae) are not a natural group.