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

Re: [Skippy innards]

        I think Ralph was right on the money with his post. 
I think dissent is great, and I think it's important because otherwise you get
sloppy. You say "I think X", and everyone agrees with you, so you never bother
to test it; people with different ideas can help break you out of this trap.
So probably the science is healthier for people like the Oregon State team
coming along and attacking our cherished ideals. And I think a lot of people
(like me) are all too willing to complacently accept things they don't really
understand the implications of or evidence for- such as endothermy, or
insulation, or tyrannosaurs running a million miles an hour, or for that
matter, tyrannosaurs being slow, stupid lumberers. On the other hand, just
because some people are maybe a little loose in the logic or data, it doesn't
mean you now get to play the same game.
        Here's an example of what I'm talking about:

        I think a telling example is the work on Megalancosaurus. Now, I have
problems with the fact that people would come out and say in a paper that
Megalancosaurus was aquatic as if there was no dispute about this. On the
other hand, the Oregon State team then came out and said Megalancosaurus was
arboreal, citing almost as little evidence. 
        To my recollection, they did not  cite the fact that the hand is 
"split" as
in koalas, chameleons, and the feet of swifts, which would greatly improve its
grasping ability by allowing the digits to act in opposition and perhaps to
grip around branches. They did not cite the fact that one of the toes is set
to oppose the other four in a manner strikingly similar to the foot of the
arboreal phalangers.They did not mention the fact that the tail, which must
have been very muscular given the size of the chevrons, and which curves
downwards in a way reminiscent (again) of chameleons, might have been
        Renesto (JVP vol 14:1 38-51) considered all these before concluding 
that the
animal was arboreal. There is even another line of evidence that can be
employed here, mainly looking at the phalangeal proportions, as Jim Hopson has
done so successfully with birds and pterosaurs (I just went and looked at the
illos of the animal, and the penultimate phalanges are very long in
Megalancosaurus, as in birds with grasping feet).  
        Now it's possible I've butchered the argument but I recall waiting to 
see if
they would bring these things up and I don't remember that they did. 

        Instead, it was concluded that the elbow joint didn't open, although I 
recall how this was supposed to have been determined without being able to
take the bones out and trying to rearticulate them and assess their range of
motion. From there, somehow, came the conclusion that this is related to
supporting a propatagium and gliding. Maybe this kind of feature abounds
nowhere but in colugos, sugar-gliders, flying squirrels and the like, but I
don't recall that this ever entered the discussion. 

        In the end, although I agree wholeheartedly that the best explanation 
at this
point is probably arboreality, and that gliding can't be ruled out, I felt
that these conclusions were not reached logically by the study. 
        Good logic would have been to say "what would this morphology have 
and might this range of behaviors permitted climbing? Are there any
similarities to gliders/climbers? A few? A lot? How do these features
facilitate climbing and gliding? Are these features explanable in other
contexts, and are they found in other animals which are not gliders/climbers?"
At least to me, it seems like they failed to bring into the discussion most of
the (considerable) evidence and argument relevant to  and supporting the
arboreal hypothesis.
        They got the right answer for the wrong reasons, which is in my opinion 
than getting the wrong answer for the right reasons. 

         It's things like this, and writing papers based on damaged fossils that
haven't been examined firsthand, and all the logical and methodological
problems brought up by Ralph (and others) that make me inclined to entirely
disregard anything they say... well, nobody's ever wrong about everything ALL
of the time, so maybe it would be a mistake to stop listening entirely. But
excuse me if I don't exactly pay rapt attention. 

> Less Hyperbole and More Rigor.
        ...hyperboles are so thick in this science, that like flocks of 
pigeons their forms fill the skies by the thousands and billions and block out
even the faintest gleam of the light of the sun.... 

> I'll also buy a beer (or diet Coke for me) for anyone that can find a Middle
Jurassic, or thereabouts, lagerstatten from a lake or coastal area that has
verts in it. Obviously that's where the action is (maybe early Upper, or even
late Early). Just gotta find some more rocks. Not asking for much, am I?
        amen to that! (but does anyone else think it's weird that there aren't 
birds out of the site that produced Sordes? Have we just not looked hard

More than just email--Get your FREE Netscape WebMail account today at