Re: Poling marks

[David Marjanovic <david.marjanovic@gmx.at>]

> Pterosaurs are front-heavy, so the foot prints are expected
> to vanish in higher sediment layers than the hand prints.
>
> > > > >
>
> Not so. Check out pterosaur info. com > behaviors for an animation of a
> walking pterosaur that actually fits the tracks. It's essentially
> bipedal using its forelimbs as canes. And, if you can imagine using a
> cane at the beach, you'll understand why the forelimbs press a little
> deeper. Less surface area.

In summer of 2004 I spent over 3 weeks in Crayssac. The hand prints are 
deeper than the foot prints.

> DM; Pterosaur walks on soft mud on all fours, many layers of
> mud get deformed, the top layers erode away, and one of the underprint
> layers ends up being published.
>
> > > > > >
>
> In every case? Seems unreasonable.

In every case where hand prints but not foot prints are preserved. There is 
no example of this in Crayssac (or at least there wasn't two field seasons 
ago).

> DM wrote:
>
> Maybe that's where the multiple naris comes in.
>
> It does not exist. It is a misinterpretation of cracks in the fossil.
> Several people have pointed this out onlist.
>
> > > > > >
> No. They haven't. Not with pictures.

I'll try at the next opportunity (...try July). You don't happen to have a 
non-descreened high-resolution photo?

> And funny that the cracks form
> identical phylogenetic patterns. That's unreasonable.

Identical to what?

> Tell me David, if _some_ poling marks turn
> out to be primary ichnites, does that change any of your hypotheses?

Yes, of course. Except I'll probably assume shallower water than you.