In his current cover story for us, Paul Nelson issued a pretty direct, clear, concrete challenge to our frequent interlocutor, the ace Darwin defender and biologist Nick Matzke.
Paul observes, as the first of three propositions:

(1) A hundred and fifty years after the Origin of Species, the evolutionary pathways from unicellular eukaryotes to any of the animal body plans remain entirely unknown.

He then asks:

Now, (1) is simply the case. If you don’t agree that (1) is a fact, choose any of the phyla — or (Nick M., I’m thinking of you), if you don’t like the taxonomic category “phylum,” choose any animal species present in the Cambrian — and send me the evolutionary pathway leading to that group from its unicellular eukaryotic ancestors. (Email me here.)

Dr. Nelson, nice guy that he is, even gave Nick an out — you could think maybe he was referring to another Nick M. But Dr. Matzke walked right into it anyway. We had the following exchange on Twitter.

Shorter Paul Nelson: I refuse to learn anything about phylogenetic reconstruction of steps of animal evo #IDerrors http://t.co/ySovCtPgvN

— Nick Matzke (@NickJMatzke) April 7, 2014

Paul Nelson prefers laziness to research due diligence, I wonder if these agree? @d_klinghoffer #PHCPensmore2014 @patrickhenrycol #IDerrors

— Nick Matzke (@NickJMatzke) April 7, 2014

@NickJMatzke Paul Nelson challenged you by name with a specific question. You’ve responded merely with attitude. http://t.co/1hNJICQLwf

— David Klinghoffer (@d_klinghoffer) April 7, 2014

@d_klinghoffer No, I noted a well-known technique for estimating evo history which has been applied here,which you & Nelson ignore #IDerrors

— Nick Matzke (@NickJMatzke) April 7, 2014

@NickJMatzke That doesn’t answer Paul Nelson’s challenge. #IDerrors

— David Klinghoffer (@d_klinghoffer) April 7, 2014

@d_klinghoffer It shows that his “challenge” put in less effort than even a D- freshman research paper on the topic. #IDerrors

— Nick Matzke (@NickJMatzke) April 7, 2014

@NickJMatzke OK, so I take that as indicating that you’re not going to answer Paul’s challenge. #IDerrors

— David Klinghoffer (@d_klinghoffer) April 7, 2014

@d_klinghoffer I won’t do your guys’ remedial intro research for you, you mean. Get real: google phylogenetic comparative methods. #IDerrors

— Nick Matzke (@NickJMatzke) April 7, 2014

Translation from the original snark: No, Nick won’t answer because he can’t. Under his paradigm, there is no valid reply. Which of course is the point.
I’m now on Twitter. Find me @d_klinghoffer.