Re: the headless juvenile Pterodaustro

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

> Here is what I saw using Photoshop at about 15% of the resolution used 
> originally.
>
> http://www.pterosaurinfo.com/pterodaustro_juv_insitu.html

Well...

As long as you don't make the 100 % resolution pic available, it doesn't 
matter what I say, because you have a killer argument: "it may not be 
visible in this pic, but it's obvious in the one I used".

Look, the 15 % pic is _so_ bad that based on that alone I wouldn't trust the 
original tracing either. The caudal series that the original authors found 
looks more like a shattered long bone, for example.

> 2. Why would a skull and cervical series decay or disappear more rapidly 
> than the rest of the skeleton? After all, this is a split slab-counterslab 
> specimen.

It is very important to remember that a fossil is not a fossil of a living 
organism or of one that has just dropped dead. A fossil is a fossil of a 
_rotting carcass_. The head falls off relatively early from rotting, 
drifting carcasses. It happens. Experiments have been done on this. The 
entire science of taphonomy studies this.

> 3. Of what use that long string tail is â?" or what an aerodynamic burden 
> it must have been â?" are beyond my ability to answer.

I'd consider this to be circumstantial evidence that that tail doesn't 
exist...

> 2. The ephemeral head and neck matches in all aspects the embryo described 
> in Nature and it resembles the skulls of adult Pterodaustro. This type of 
> soft crest is seen in a skull-only specimen and in other ctenochasmatids. 
> The gular sac is to be expected.

The borders of the dewlap and crest look more like mineral inclusions... 
note that you didn't find a crest at all, you found the _boundary_ of the 
crest, and inferred everything between it and the alleged bones must be the 
crest, even though it looks like the matrix outside the white boundary 
feature and _not_ like the boundary.

Why do you interpret one bright (apparently raised) area as the rostrum, but 
two or three other such areas not at all?

> 3. Pterodaustro is already known to have a longer tail than is typically 
> seen in ctenochasmatids - which leads one to wonder about the others since 
> Pterodastro is the most highly derived form known.

"Derived" doesn't mean that all features of the skeleton are compelled to 
evolve at the same speed or _at all_. The days of orthogenesis are over. 
Tell me a candidate for "the most derived mammal", and I'll find you at 
least one plesiomorphy that it has and we lack.

Oh -- the tail -- note that the extra part of the tail bifurcates. The part 
your tracing doesn't contain branches off so that it looks like a 
continuation of the left foot.

> 4. The 'pterodactyloid' kite tail with fletching (vane) is known among 
> other pterosaurs, but always poorly ossified in 'pterodactyloid'-grade 
> forms.

A cartilaginous tail is a bizarre thing... why isn't it just composed of 
ptero-hair instead...

> 5. Wing unguals and manual digit V are also seen, but rarely reported, in 
> most other pterosaurs. Typically they do not preserve as well.

Must be because they're ossified like the rest of the skeleton... aren't 
they?

I thought I had seen the "wing ungual" (means, a _vaguely_ triangular white 
spot in continuation of the wing that points to the left, but separated from 
it by a black line). But no, you interpret it as a peculiar knob at the end 
of the 4th wing phalanx, and the next _two_ white spots (separated from each 
other by a black line) are what you interpret as the ungual. This really 
looks like preassuming something is there and then trying to see it. Like 
the two unassociated lumps of rock that are together vaguely triangular and 
form the head of the *Cosesaurus* that is being born. But I think the killer 
argument comes into play here.

Besides... where should the 5th finger, which even retains a claw, be in 
life? In the wing membrane? What function could it have had that saved it 
from being lost in the Triassic?

The claw of the other wing finger is much lower and thinner. I guess that's 
because it's one white spot and not two like the other.

I could go on if it weren't half past two at night.

> Now, whether what I see is valid or not, at least I hope there's no 
> question that this technique can be useful for sharing data quickly and 
> precisely.

Provided that the used photo is detailed enough for _data_ to be found.