Primitive beetle taxa

Ken Kinman kinman2 at YAHOO.COM
Fri Feb 11 16:02:43 CST 2005


Dear All,
      I don't consider this a fundamental change of topic (it seems interconnected to me), but I guess I'd better change the subject line for those who think it is.   QUESTION 1:  If Polyphaga is a derived suborder (as the "Tree of Life" website shows it), does this mean that the earliest beetles had lost their cervical sclerites, and then these structures then suddenly reappear at the base of Polyphaga?  Not very parsimonious in my opinion.    QUESTION 2:  Why are telotrophic ovarioles of Polyphaga referred to as a derived feature, and their occurrence in some of the Neuropterida labelled as a parallelism?  Could this perhaps be the result of circular reasoning?   QUESTION 3:  Why are the hind wing venation patterns of non-Polyphagan beetles generally referred to as plesiomorphic.  Do such venation patterns occur in closely-related insect orders, or is this again a possible circularity problem.  It might sound like I am just being rhetorical, but I would truly like to know if there is any really strong support for a derived Polyphaga in beetle cladograms.  This seems problematic to me, but perhaps someone can convince me otherwise.
     ----Thanks,
               Ken
P.S.  I must admit I was impressed by the "cryptopleuron" character, although I was less so once I realized that Myxophaga also have a fused pleurotrochantin (and apparently can be somewhat "cryptic" in that group as well).  Can one really rule out the possibility of a cryptopleuron evolving into a more exposed structure?




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