[Taxacom] sloppy cladistic analyses

[John Grehan]

The comments on Collembola and Strepsiptera points to the fact that the
relationships of some groups may remain forever irresolvable. There is
no necessary reason why any character, molecular or otherwise, should
necessarily lead to an unambiguous relationship for every group. If
spatially vicarious differentiation is the norm in phylogeny one may end
up with character combinations in descendant taxa that do not necessary
track the divergence sequences, whether or not one uses cladistic
criteria for character definition.

John Grehan


> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Stephen Thorpe
The situation is similar
> with the Strepsiptera problem: they could be derived beetles, they
could
> be derived flies, they could be the sister group to one or more insect
> orders? It does not seem possible to decide. To my somewhat
pre-cladistic
> mind, however, this makes them exactly what an independent order
should
> be, namely a group of obviously related taxa that aren't obviously
related
> to anything else ...
> 
>