[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: The pterosaur in the egg: a new report
> The latest issue, #67, of the Prehistoric Times (www.prehistorictimes.com)
has published new tracings of the bones within IVPP V13758, the Chinese
pterosaur in the egg. I eagerly encourage anyone with an interest in the
subject to check it out.
Could someone perhaps send that pic my way? I can't get Prehistoric Times
(at least not anytime soon). I have, however, checked out the relevant page
at http://www.pterosaurinfo.com/. See below.
> I found a complete skull, mandibles with teeth, palate, occiput and
sclerotic ring followed by a complete skeleton down to the fingers and toes.
You found... teeth? Does that mean you found enamel and/or dentine?
> Perhaps these can be ascribed to the sedentary nature of its prey,
Is anybody trying to make a thin slice of the eggshell? That would tell if
it comes from a dinosaur.
Also, if it's an egg-eater, why is the pterosaur curled up so neatly inside
> The new pterosaur fits neatly into a large cladogram. Using 178 characters
and more than 100 taxa,
While I respect your work, which is more than anything I've ever done, I
have to say that your analysis suffers from the same problem as mine,
despite the smaller extent of the problem: you have too few characters for
that many taxa.
> Both Nature and Science were offered the anurognathid manuscript and both
Below I'll show why.
> Of course this is only the first challenge to the pterosaur egg theory.
I've produced a more detailed tracing of the specimen than was previously
offered. If anyone wants to oppose the new hypothesis, offer a defense or
specifically show where the drawing is in error, it would seem to be good
science to produce another tracing of equal or better detail showing the
error(s). I look forward to some good science.
Could you send me... oh, sorry, I forgot you can't send large pictures via
e-mail... :-( well, I'd like to try a tracing of the jpg you received. I'll
certainly not do a tracing of the low-resolution pic from Nature. If there's
a way -- perhaps snail-mail -- to send your pic my way, I'd appreciate that.
> and you all know what can happen following a size squeeze.
Err... you can get mammals, or dinosaurs. Neither basal mammals nor any
known dinosaurs are (ovo)viviparous, so I don't know what you mean.
Here are quotes from the website (all [brackets] in the original):
"There is no argument that Wang and Zhou described a pterosaur in an egg and
that most, if not all, previous specimens inside of egg shells have all been
embryos. Rumors of an Argentinian pterosaur in an egg shape [without shell
fragments] were also circulating. Why then should anyone even look for
another explanation? There appeared to be no argument - except that I had
found 40 soft and ephemeral examples to the contrary over the past year."
Which nobody but you believes to actually exist. As mentioned above, I'd
like to try myself, but for the moment I'll think they are all faces and
pyramids on Mars.
BTW, Nature 429: 623 is "Eight glacial cycles from an Antarctic ice core".
You mean 621.
"I had three immediate clues that the pterosaur in the egg was not what it
seemed. 1) The mother was not preserved nearby;"
Why should she be preserved nearby? Imagine the nest was on a tree, and this
egg fell out of the nest and into a lake.
"2) the bones were well-ossified;"
Except tarsals and the small toe bones, they _should_ be well-ossified in
_any amniote_ that is near hatching or birth. Now let's see what the article
says: "Both the lower jaw and the limb bones are characterized by less
ossified epiphyses and an immature grainy texture[...]. The scapula is not
fused with the coracoid. The vertebral column, carpal bones and pedal digits
are also incompletely ossified." This sounds like what is expected for an
amniote of that age.
"and 3) of the few bones in the jumble that were readily identified, the
tibia was longer than the femur. Readers of PT (64 & 65) will recognize that
the latter clues are signs of post-independent and adult pterosaurs."
Why is such a tibia-femur ratio a sign of an adult or subadult pterosaur...?
A bit later you say that "no ossified pterosaurs have a tibia shorter than
the femur". Why don't you entertain the possibility that this means that no
pterosaurs at all have a tibia shorter than the femur? Why are you _so_
certain that what you see in your tracings is real?
"2) most precocial embryos have ossified bones;"
_All_ amniotes that are close to hatching or birth, precocial or altricial,
have ossified bones. They may or may not have ossified epiphyses, but they
have lots of ossified bones.
"In the end Wang and Zhou concluded they had found the embryo of an
ornithocheirid pterosaur, but one with a decidedly short mandible.
Unfortunately, no ornithocheirid has such a short mandible. Of course, the
jaws could have elongated with maturity, they reasoned. Tiny pterosaurs from
the Solnhofen Formation, long considered to be babies, do have a short
rostrum and big eyes."
Human babies also have a short rostrum and big eyes. Frog babies have a
short rostrum and big eyes. Shark babies have a short rostrum and big eyes.
Each and every juvenile vertebrate has a shorter rostrum and bigger eyes
than its parent(s) (parentheses for parthenogeny). If we found a headless
young ornithocheirid, we'd automatically reconstruct it with a short snout
and big eyes -- for _very_ good reasons.
"Unfortunately for that bit of long-standing dogma, recent cladistic
analysis has revealed these to be tiny adults close to Scaphognathus."
This is a fallacy. Cladistics is not magic. Cladistics cannot _possibly_
find out if the characters you feed into the matrix are ontogeny- and/or
size-related. It is _incapable_ of such stuff. If pterodactyloids were more
peramorphic than other pterosaurs (like humans look much like chimpanzee
babies), we'd _expect_ to find juvenile pterodactyloids, if used as OTUs,
closer to the base than adults.
"Some even have tiny babies of their own!"
You find some. Does that really mean they exist?
"So what was an adult anurognathid doing in an egg shell? That can only be
guessed at. However, considering the size of the first premaxillary teeth
and the robust nature of the rostral and palatal bones buttressing them, it
is a good guess that this pterosaur used its front teeth to crack the shells
of eggs larger than itself, like the one it was found in, probably a
The skull of the beastie (your fig. 1) does indeed look well-suited to
cracking eggs, except that the lower jaw is quite thin in the middle. But
here I'm talking about eggs the size of its eyes, not the size of its entire
body. The teeth are about as long as the eggshell is thick, if not less!
And look how tiny the trunk you've reconstructed is. The beastie
looks like a hatchling even compared to *Dendrorhynchoides* and
*Anurognathus*, determined to fall on its chin from its unsustainable
bipedal pose -- and subsequently unable to lift its head off the ground.
Judging from your reconstruction, it's a baby, and not a precocial one --
or, alternatively, still below hatching size.
"Figure 2. Reconstruction of Dendrorhynchoides from China, along with a
half-sized juvenile and a neonate. Reconstruction of the pterosaur in the
egg (IVPP V13758). A new name is required of every new genus and species.
*Avgodectes pseudembryon* translates from Greek as 'egg-biter, false
Reconstruction of Anurognathus from Germany. Scale bar, 5 cm."
I don't know Greek, but the usual prefix used for "egg" is oo-... Is
*Oodectes* preoccupied? ~:-|