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On pterosaurs and photoshop (was Re: Good news for Eosipterus fans)



I still see nothing! The skull you are talking about doesn't exist!

I say that one should take a good look at the actual specimen before making
assumptions. After taking a look at all these threads I'm starting to
wonder, why hasn't Dave Peters taken into account preparation work,
deterioration, age, glue stains, paint stains, etc., these all have a huge
effect on how the fossil looks. The "babies" you talk about could also be
the result of lumps of sediment or some fosilized invertebrates. I say that
its time to go back to those "old school" methods rather than picking out
every single feature in the rock and then saying that its a dorsal frill, a
bone, a baby, etc. IMO having an open mind in paleontology is great but when
taken too far, open-mindedness can cause the paleontologist and his/her
audience much trouble and misguidence. looking at things in photoshop will
never prove better than having the actal fossil in one's own hands to study

----- Original Message -----
From: "David Peters" <davidrpeters@earthlink.net>
To: "dinosaur list" <dinosaur@usc.edu>; "Lu, Junchang"
<junchang@mail.smu.edu>; "Kevin Padian" <kpadian@socrates.Berkeley.EDU>
Sent: Saturday, March 29, 2003 12:10 PM
Subject: Good news for Eosipterus fans


Hi gang,

Previously it was reported (refs below) that the Chinese pterodactyloid,
Eosipterus, lacked a head, cervicals, and a good humerus. I don't know
how we all missed this before, but there is a giant skull in the middle
of the plate from top to bottom, two mandibles on the right half of the
plate, and the humerus is well marked. Scleral rings are present and so
are lots of articulated teeth. The back of the skull is disarticulated,
but that's good news because access to the specimen should provide a
good look at the braincase and palate.

It's a skull quite like that of Germanodactylus rhamphastinus, with a
sharp but toothy premaxilla (well dilineated with four teeth) and a
total length equal to the occiput-vent length. Dr. Unwin and I have
discussed the relationships of Eosipterus privately. It's nice to have
confirmation that one can judge a germanodactylid by its metatarsus.

It may also be a testament to the scanning technique. I used the small
(less than 2x2") color picture that appeared in Nature (see below)
whereas others had access to the specimen. I'm sorry I missed it
earlier, but  I followed previous reports which I assumed were factual,
rather than relying on my number one roadkill rule: if it's articulated,
it's complete.

In addition, there are a few bits and pieces from other pterosaurs, as
I'm finding is typical of lacustrine deposits - none are quite small
enough to fit into the newborn category.

The dorsal frill and lots of skin in the form of wing membranes and
uropatagia are present. These stains and shapes may have confused
earlier workers and added to the apparent chaos. In contrast to earlier
reports, Eosipterus may yet provide a treasure trove of information.

For those of you who still regard the scanning technique as inferior to
actual observation of the fossil, perhaps this ?little discovery will
quietly sway a few to some small degree of acceptance. Once again I say,
the new technique merely places order on the apparent chaos of a
roadkull fossil, enabling careful dilineation of every bump and stain so
that all parts of a fossil can be identified, rather than dismissed or
ignored.

Now that we know where the skull is, good first-hand observation should
be the next step. Let's look for those cervicals!

More later,
David Peters
St. Louis


Ji S.-A. & Ji Q. (1997) Discovery of a new pterosaur in Western
Liaoning, China. Acta Geologica Sinica 71(1), 1-6 [in Chinese]. 71(2),
115-121 [in English].

Ji S.-A., Ji, Q. and Padian. K. (1999) Biostratigraphy of new pterosaurs
from China. Nature 398: 573-574

Unwin, D.M., Lü J. and Bakhurina, N.N. (2000) On the systematic and
stratigraphic significance of pterosaurs from the Lower Cretaceous
Yixian Formation (Jehol Group) of Liaoning, China.  Mitteilngen der
Museum für Naturkunde in Berlin, Geowissenschftlichen Reihe 3,181-206