[Darren Naish: On idiosyncrasy in pterosaur-land]

[Mike Taylor <mike@indexdata.com>]

Forwarded from Darren, by request.

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Date: Fri, 8 Jun 2007 13:00:12 +0100
From: "Darren Naish" <eotyrannus@gmail.com>
To: "Mike Taylor" <mike@indexdata.com>
Subject: On idiosyncrasy in pterosaur-land

Mike - any chance you could please fwd this to DML for me? Thanks..

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WRT Dave Peters' message 'idiosyncrasy in birdland', I thought that - given
that I was charged as one of the workers ignoring 'the elephant in the room'
- I'd respond.

David: obviously your efforts to document pterosaur phylogeny and origins by
way of comprehensive character analysis are worthwhile pursuits. While there
is still some completed work to appear on how your proposed phylogenetic
schemes match up with the evidence (recall that Dave Hone referred to
unpublished material in his phd thesis), I would argue that there is a very
good reason why your phylogenies are not being accepted as the most
parsimonious: this is because your choice of characters, and coding of them,
rests on your photo-interpretation technique. I've said it before and I'll
say it again (and everyone else I've spoken to says the same) - none of us
hold any confidence in your many unique interpretations of pterosaur bones
and teeth, soft tissue crests, frills and tail-whips, multiple babies etc.
Every time I (or anyone else I've heard from) looks at pterosaurs,
_Longisquama_, _Sharovipteryx_, _Huehuecuetzpalli_ or whatever, we come away
rejecting your multiple unique interpretations. As discussed in personal
correspondence, I have found that your photo-interpretation method has led
you astray on _Istiodactylus_, _Tupuxuara_, and Solnhofen _Pterodactylus_
and _Rhamphorhynchus_ specimens, and I have heard likewise from workers with
first-hand experience of the Triassic taxa that are integral to your
prolacertiform/squamate origins hypothesis. You are coding characters and
character states that are not present.

The conclusion is that your data sets are cluttered with a significant
amount of irrelevant noise (I'm not sure how much, but recall it looking
like more than 50%), hence the lack of acceptance. Sorry, but my ideas on
this haven't changed, nor have those who have criticised this aspect of your
work in the past. And this isn't me being nasty, as I was initially _really_
impressed with your 'four prolacertiforms' paper.

All the best.

Back to storm prediction in butterflies...

-- 
Darren Naish
School of Earth & Environmental Sciences
Burnaby Building, Burnaby Rd
University of Portsmouth
Portsmouth, UK, PO1 3QL

tel: 023 92846045
visit my blog: http://scienceblogs.com/tetrapodzoology/
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