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RE: something's wrong here: Qianosuchus phylogeny
Most of your complaints are ridiculous, as you often say "derive x from y"
when in reality, the situation is "derive the common ancestor of w and x
from their common ancestor with y". The way to argue against phylogenetic
relationships isn't by stating a few reversals you personally find
incredulous, or noting a couple characters you find to be unparsimonious.
Obviously it's to perform a phylogenetic analysis. Which you did, but the
character list is unpublished. If it's anything like your pterosaur
analysis character list, it's untrustworthy. Most of those were correlated
with others and/or incorrectly formed. For instance-
"19. Naris size/shape: 0) narrow to oval; 1) huge; 2) rotated dorsally; 3)
secondary naris present."
This is a terrible character. The states aren?t equivalent at all. State 0
is naris shape, state 1 is naris size, state 2 is naris orientation, state 3
is number of nares. Divide into 4 characters, each describing one
So despite your laudable goals of more characters and low level OTU's, your
character construction flaws your results. For what it's worth, I tried an
archosaur analysis with 92 taxa and 132 characters (from Benton, Parrish,
Sereno, etc.) and always got mostly standard results as far as which taxa
were crurotarsans vs. avemetatarsalians, and which were basal to crown
archosaurs. And yes, Triassolestes, Turfanosuchus and Pseudohesperosuchus
were included. Crurotarsan phylogeny was quite odd though, and more
characters were needed for so many taxa.
From: david peters <email@example.com>
Reply-To: david peters <firstname.lastname@example.org>
Subject: something's wrong here: Qianosuchus phylogeny
Date: Fri, 31 Aug 2007 14:09:23 -0500 (GMT-05:00)
Thanks to Matt Celeskey, I now have the pdf of the Qianosuchus article. So
Fabio, if you're still interested, I can send you a copy.
The strict consensus tree in the accompanying pdf file looks 'traditional.'
By that I also mean 'bogus' as many of you already know. Let's start the
rant right here:
Prolacerta > Proterosuchus > Erythrosuchus > Euparkeria is all just fine.
Then the trouble really starts.
Can anyone tell me how you derive Proterochampsidae from Euparkeria? That's
quite traditional in many trees. But it's so wrong. Can't we find any other
taxa to fill this gap? What about Vjushkovia?
Then, can anyone tell me how you derive the so-called 'Crurotarsi' from
Proterochampidae? Phytosauridae, yes. But say no to Stagonolepidae,
Gracilisuchus, Rauisuchidae, crocs and the rest. Look above the ankles!
Look at the nares!
Also arising out of Proterochampsidae: Scleromochlus! What??? Put those two
side-by-side in a PowerPoint presentation and listen for the giggles. They
almost could not be more different.
But wait, it gets worse: Pterosaurs arise from Scleromochlus and its
unknown sister taxa!!! Suddenly the smallest hands in all creation become
the largest! And that stub of a metatarsal 5 becomes a highly specialized
retractable toe??? Bogus. I know, I know, we're talking about sister taxa
here, but you have to go pretty far back in this family tree to get that
toe to grow back.
Then Lagerpeton arises from the sister to pterosaurs? I don't think so.
It's closer to Tropidosuchus and then Chanaresuchus and then
Proterochampsa. So we skipped a generation. And toe five is gone again.
Out of Lagerpeton arises Marasuchus, even though the hips and toes don't
match. Now it would be good if Marasuchus could arise from a sister to
Scleromochlus, with which it shares so much more. Again, we skipped a
Last but not least, theropods arising out of sauropods and ornithischia?
Shouldn't that be the other way around? Aren't theropods closer to
Marasuchus in every way? Sharp teeth, reduction of digits, etc. By the way,
toe five makes a return in some of the above.
No wonder the authors were not able to figure out where Qianosuchus nested.
They needed the following taxa: Triassolestes, Turfanosuchus,
Pseudhesperosuchus. They need updates to Ticinosuchus. They also need more
characters. That dorsal nose in Q. is very much like what is seen in
aetosaurs, by the way, which are also derived from Ticinosuchus. So, not
sure if that tall slender tail of Qianosuchus is swimming. Especially
considering that the transverse processes that would have anchored the tail
rectractors are really hard to find.
The world view of traditional workers is that someday some series of taxa
will fill in those currently untenable gaps in the evolution of one form
into another. There's a simpler solution. It's called parsimony. We have
enough taxa to make it work so that sister taxa seem to blend into one
another morphologically, but they must be used. And when all the work is
done, you have to step back, take a look at the whole thing and ask
yourself: "Does this make sense?" remembering that evolution works in tiny
Last rant: specimen-based studies: good. Suprageneric-based studies: bad,
as shown above.