[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Longisquama OFFLIST

Actually, by the grace of Tim. The term OFFLIST means the message has been sent 
to you and Paula, Tim, NOT to the List. You just made it public. Not that there 
is anything wrong with the message, but the intent was to keep it OFFLIST.

With regard to Senter's thesis, is the matrix available? 

What characters are used here?

I note no traditional squamates here. No pre-squamates (sphenodontids, 
owenettids, procolophonids, captorhinids, etc.) either. So, some of these 
nestings without such testing are by default, as I have mentioned earlier. When 
someone brings a few lizards into Senter's cladogram, just for grins, let me 
know the results. Then we'll set the bar.

And once again, how do you get hypertrophied digits from atrophied digits?

David Peters
St. Louis

      |  |--Longisquama
      |  `--Megalancosaurus
               |  `--Palaeopleurosaurus
                  |  `--Hyphalosaurus
                     |  `--+--Prolacerta
                     |     `--+--Macrocnemus
                     |        `--+--Sharovipteryx
                     |           |--Langobardisaurus
                     |           `--Cosesaurus
                              |  `--+--Ornithosuchus
                              |     `--+--+--Saurosuchus
                              |        |  `--Postosuchus
                              |        `--+--Gracilisuchus
                              |           `--+--Sphenosuchus
                              |              `--+--Saltoposuchus
                              |                 `--+--Dibothrosuchus
                              |                    `--+--Alligator
                              |                       `--+--Malawisaurus
                              |                          `--Protosuchus
                                 |  `--+--Eudimorphodon
                                 |     `--Austriadactylus
                                    `--44 dinosaurs + 7 birds

Re: Longisquama OFFLIST


To: dinosaur@usc.edu 
Subject: Re: Longisquama OFFLIST 
From: Tim Williams <twilliams_alpha@hotmail.com> 
Date: Wed, 20 Jun 2007 19:49:03 -0500 
Reply-to: twilliams_alpha@hotmail.com 
Sender: owner-DINOSAUR@usc.edu 


So, I guess this was "For Paula's Eyes Only", but by the grace of God it 
arrived on this list...

David Peters wrote:

Longisquama is most closely related to pterosaurs as I showed in a 2000
paper in Revista Italiana and in later analyses that were much more
comprehensive. Senter's analysis used too few taxa and too few
characters to nest anything with confidence, but instead relied on

Neither Peters's or Senter's analysis should be regarded as the Final Word on 
_Longisquama_'s affinities. However, most professional researchers put more 
faith in Senter's phylogenetic analysis due to certain methodological problems 
with Peters's study. As an example of the reasons why, refer to 

Nothing personal. It's just that Senter's study set the bar higher than 

Longisquama has a single line of dorsal plumes, analagous and perhaps
homologous to the frill on a Tuatara, Iguana and Basilisk.

For the "single line of dorsal plumes" - this is probably the case; not 
definitely. The suggestion that the plumes are "homologous to the frill on a 
Tuatara, Iguana and Basilisk" is much more speculative.