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Posted by Carl Brune on December 16, 2002 at 11:02:48:
In Reply to: subspecies - useful or not? posted by troy h on December 10, 2002 at 12:00:43:
Your criteria are logical, but I see problems. What do you do if subspecies based on pattern/scalation do not agree with those based on genetic analysis? For example, as I understand it, traditional subspecies of Elaphe obsoleta and Sceloporus undulatus are not supported by genetic studies. If the variations in pattern/scalation are correlated with geography/vegatation these characteristics may result from convergent evolution rather than genetic simmilarity.
Have you checked out Grismer's Baja Herp book which utilizes "pattern classes" rather than subspecies? My first reaction was that this approach was a cop out, but I am starting to appreciate it more. Perhaps (??) we need two systems, one for classifying phylogenic relationships, one for "pattern classes". It would be useful to a have a way to refer the "yellow ratsnake" which is unambiguous but does not necessarily imply anything phylogenically.
There is one point which bothers me about the genetic studies at this differentiation level (e.g. E.obsoleta complex or S.undulatus). As I understand it most if not all of these analyses assume a priori that the data can be fitted by a tree topology. In other words every geographic locality is assigned a position in the tree (a leaf?). However in a freely interbreeding population it seems this picture is too simple. The true topology which reflects genetic relationships must be more like a fishnet than a tree. Disclaimer: My formal education in biology stopped in the 9th grade, the above comments are just my observations...