Another example of narrow chord pterosaur wing on the 'net

[David Peters <davidpeters@att.net>]

This link, or simply googling images for "Ctenochasma elegans" will get you 
there.

http://images.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/8/8c/Ctenochasma_elegans.png&imgrefurl=http://commons.wikimedia.org/wiki/File:Ctenochasma_elegans.png&usg=__7GDhp3WU1u9p0TxN9jpjoEewVjA=&h=2040&w=2238&sz=10207&hl=en&start=1&um=1&itbs=1&tbnid=yX67GIU6Q0q1FM:&tbnh=137&tbnw=150&prev=/images%3Fq%3Dctenochasma%2Belegans%26um%3D1%26hl%3Den%26safe%3Doff%26sa%3DN%26tbs%3Disch:1



This is an ROM specimen attributed to Ctenochasma elegans, but that's dubious 
and irrelevant. Again, a wee bit of camera shake here. Resolution is 2000+ 
pixels square.

Here some (not all) of the wing membrane is preserved, either as orange colored 
material or as impressions of a trailing edge that continue in its place. The 
wings are folded. A distal membrane trails m4.2 and a continuing line trailing 
m4.3 is nicely folded in, but that's not what we're looking for. 

The bright orange membrane with a distinct trailing edge posterior to the upper 
elbow is narrow. Darn it, it terminates just where it gets interesting on a 
bulge in the matrix. Both wings cross the femur (the one ventral to the torso) 
at the presumed (in the narrow chord model) point of attachment. This patch is 
inboard (anterior) to both distal wing membranes. It covers the deeper elbow. 
It has a concave bend at the predicted turn toward the femur. 

Evidence on the other (dorsal to the torso) femur is weaker. The color of the 
matrix simply dulls sharply at the predicted attachment point. Since the left 
elbow and knee are so far apart here the membrane has been stretched beyond its 
in vivo limits. 

Evidence for any other sort of wing attachment is weaker still.

ALSO ~

The famous Zittel wing (with narrowing toward the elbow) is here:

http://science.nationalgeographic.com/science/enlarge/reptile-wing-fossil.html

AND ~

David Hone provides the Vienna specimen (with narrowing at the elbow and a 
distinct line to the femur) here:

http://archosaurmusings.wordpress.com/2009/04/13/where-is-the-pterosaurian-5th-finger/

As  a side note that the propatagium attaches to the deltopectoral crest, not 
the neck!

>From such clues we build a case. Some are better clues. Some are weaker. The 
>trend is in one direction only. If there are other examples out there, please 
>make them known.

David Peters
St. Louis