New Squamate classification

[John Grehan]

From: Taxacom Discussion List on behalf of Ken Kinman



Dear All,
      As usual, I disagree with Grehan's broad generalizations about morphology trumping molecular data.  

As 'usal' I'll have to correct Ken and point out that it not my general position!

It is certainly unfair to suggest that "the authors don't even consider morphology a science".  On the contrary, they go into some detail how their molecular phylogeny is supported by morphological evidence (although it correlates with morphological characters traditionally seen as homoplastic, and characterizes some of the older characters as homoplastic instead).  Morphology is still seriously considered and different morphological characters shown to be correlated with the molecular data.

I would argue, based on what Ken has said, that the author's position is just what I said. Morphology is convenient when it supports DNA sequence simialrities, and inconvenient when it does not. In the latter it is cast aside.

      Therefore, if there is any major criticism to be leveled at this paper, it is that they should not be too quick to dismiss a relationship between varanids and snakes.  Since groups like mosasaurs and aigialosaurids are extinct, this is something that paleontology will eventually settle, NOT the molecularists.  

The irony here is that is possible only if morphology can stand as a science in its own right and not be automatically over-ruled by contradictory sequence similarity. That is my basic position.

Otherwise, I think the molecular phylogeny is very informative and extremely interesting.  

It might be, although if it has no nececssary connection to morphology the infrormation content may be problematic.

If we are going to criticize them, let's be more s
 pecific (not vague broad-strokes like morphology vs. molecular, which is not very helpful).

The issues here are general as well as specific. I'm interested in the general issue of morphology and sequence similarity. Ken is not.

John Grehan