leaf or wing?

[Silvio Renesto <renesto@mailserver.unimi.it>]

This is on behalf of David Peters
                                        Silvio Renesto

Chris Bennett wrote:

>> Lastly, I'm no paleobotanist, but isn't the thing that is described
as "Tip
of wing showing aktinofibrils" in Fig. 17 and also visible in Figs. 1
and 2
a leaf?  I do not see any evidence of wing phalanges on either margin.
The
striations which are presumably interpreted as actinofibrils in Fig. 17
are
not arranged in the pattern seen in the Zittel wing and other undoubted
pterosaur wings, where they extend obliquely in a posterolateral
direction
from the wing finger, but rather the striations seems to be the parallel

venation in a leaf.  If this is a leaf, then the details and
interpretation
of the diamond pattern in Figs. 18 and 19 are suspect.<<


In my scan of the image (don't know which plate, but it represents the
entire fossil, not a closeup) I see manual phalanges 4.3 and 4.4  along
the right margin. A bulbous joint is at their union. They, together with
the other wing phalanges exposed in the same zone can be reconstructed
as a wing not unlike that of Dorygnathus in size and proportion. The
distal end of the terminal digit is bent medially, as often happens in
Rhamphorhynchus. Chris is right, the striations appear to parallel the
leading edge of the wing, but at this scale, I would hesitate to refer
to them as actinofibrils. Perhaps they represent some sort of taphonomic
condition.

If it is indeed a leaf, it's a dead ringer for a pterosaur wing. Reverse
mimicry?

Will suffer the consequences if a closeup fails to confirm.

Share this if you think it is appropriate.

David Peters