Re: Some Observations on Nyctosaurus

["Jaime Headden" <ja_headden@qilong.8m.com>]

Chris Bennett (cbennett@bridgeport.edu) wrote:

<This tells me that these elements are intimately associated with the wing.>

  Which is why I brought up the taphonomy. Transport in a direction, in any 
current, even 500 m down or so, will still favor
orientation of long bones. One would assume the smaller, lighter bones would 
move farther, and be prone to loss more than the
heavier bones. But what we see is the absence in KJ1 of much of the hindlimb 
and vertebrae, in KJ2 of the vertebrae, pelvis, and
legs, and massive distance between the paired wings and the skull elements, 
which does not occur in KJ1. I was curious as to reasons
why, and how this affects some of the lightest elements, the wingbones, why the 
crest, apparently much more thin-walled than the
wing bones, remained largely in articulation and association as in life. These 
have a lot to do with, as I think, some of the
identifications of elements, which is why in my second observation, I tied them 
together.

<You are mistaken.  As I wrote in the paper, one form of ossified tendon is 
flat and has "a striated appearance indicating that it
was made up of multiple fibers before ossification", but the other is round in 
cross-section, does not have a striated appearance,
and bifurcates at one end.  The second morphology  is tendon and clearly does 
not pertain to metacarpals I-III, and note that I
clearly stated that there is no evidence of Mc I-III in either specimen.  I do 
not have time to discuss the evidence here, and I
suggest that you wait until I complete the thorough redescription and revision 
of Nyctosaurus that is in progress.  Note that the
Pal. Zeit. paper was simply to document the crested specimens--they are 
privately held and as you may know it is difficult to
publish on privately held specimens in U.S. journals.  Therefore, I simply 
wanted to get a thorough description of those specimens
published so that in my redescription and revision I can refer to the 
information provided by them by citing the Pal. Zeit. paper
without having to describe the specimens.  As a result, detailed discussion of 
the osteology of Nyctosaurus including the questions
of the ossified tendons and Mc I-III was put off for inclusion in the 
redescription and revision.>

  Forgive my limited foray into osteopathy, but do not ossified tendons, with 
the possible exception of some mole limbs, fuse to
bone or are tightly associated with bone? Such non-associated tendons in the 
moles (*Talpus* [?] has an forearm extensor tendon, a
unique tendon for mammals) have indistinct ends and show poor and porous, 
incomplete ossification, developing late in ontogeny, as a
factor of stress in the tendon itself.... Though I do not wish to force you to 
discuss something that is in prep for elsewhere, I am
curious why these "tendons" are so easily identified as such, as they are free, 
ossified, and apophyseally well-formed "struts" do
not fit known ossified tendons? This is only my question, which I feel was 
warranted given the availability of the paper that
identified these elements unequivocally and without alternate id's as tendons, 
unless one would rather we not discuss it.

  You write "clearly does not pertain to metacarpals I-III, and note that I 
clearly stated that there is no evidence of Mc I-III in
either specimen." and that's my point. Identifying these as tendons suddenly 
predicates the absence of mc's I-III if they WERE mc's
I-III. It's not logical to state that they were tendons, and there is no 
evidence of other bones they COULD be. They are
predominantly associated with the carpus and propodium, which either makes they 
VERY odd means of ossifying forelimb tendons, or
likely candidates as metacarpals. Or something odder....

<Do I really look dumb enough to publish a paper describing new crested 
Nyctosaurus skulls and comparing them other Nyctosaurus
skulls and not include all available Nyctosaurus skulls?  Wait, don't answer 
that. Anyway, I am not that dumb!>

  Before this devolves into an argument, I would like to point out that my 
observations were scientific and not in the least
antagonistic. I was asking questions because of a wish to know.

<The specimen that you refer to is FHSM 2148,>

  Which I did not know.

<...and I did discuss it.  I also discussed the Field Museum specimen, FMNH P 
25026, which was described by Williston, and the
Carnegie Museum specimen, CM 11422. Before you get upset and ask about the 
Nebraska specimen, I will point out that its skull
exposed and eroded and all that was left was the anterior part of the beak(s).  
The structure on the premaxilla that apparently
looks like a crest to you is an artefact, the result of damage to the specimen 
and inaccurate reconstruction by Sternberg--one can
do all sorts of bizarre things with plaster and brown paint, but that does not 
make them real. There is no evidence in Nyctosaurus
of a median crest on the premaxilla like that of Germanodactylus, etc.  Note 
that I already commented on just this point, which was
brought up by David Peters some time ago.>

  And that, I think, adequately answers my questions, very thankfully so. I so 
no reason why the first three sentences of the quoted
paragraph were neccessary, however.

  Cheers,

  Jaime A. Headden

  Little steps are often the hardest to take. We are too used to making leaps 
in the face of adversity, that a simple skip is so
hard to do.  We should all learn to walk soft, walk small, see the world around 
us rather than zoom by it.

  "Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)