THE MIDDLE OF SAUROPOD FACES

[Tetanurae@aol.com]

Berislav Krzic wrote:
<<Nemegtosaurus had a very long narrow cranium. In original Polish paper it
 was featured having diplodocid like nasals.>>

Indeed, Nowinski did describe it as having short nasals like those seen in
dipolodocids, but he also took quite a bit of artistic lisence when
illustrating most of the face.  Instead of looking at the drawings, take a
look at the plates.  The dorsal surface of the face is missing from near the
tip of the snout all the way to the very caudal end of the nasals.  In other
words, the caudal premaxillae, the dorsal rami of the maxillae, dorsal
portions of the lacrimals, and most of the rostral ends of the nasals are
missing.

Parts of the nasals ARE there however and seem to indicate a wide-based nasal
process that points rostrally from the braincase, and which narrows as it
increases in length.  Unfortunately, the nasals are broken off very close to
their cadal ends, so we cannot know for sure their true size and shape.
Nowinski draws them too short (in my opinion), and with almost no rostral
process.

<<Is there any material proof for the brachiosaur-like nostril, except a
"missing, ghost part"?>>

Well, the nasals seem to exit the rear of the head at an up-turned angle from
the long axis of the skull.  Additionally, there seems to be that premax-max
shelf on the snout seen in camarasaurs and brachiosaurs.

<<If I am correct, isn't the same part of the skull missing from Dicraeosaurus
and
 Quaesitosaurus, too?>>

The skull of Quaesitosaurus is missing most of the middle section, but the
snout does seem to have a shelf like that seen in Nemegtosaurus, Brachiosaurus
and Camarasaurus.  

Jeff Wilson has shown evidence that Quaesitosaurus has been really crushed,
and it  probably belongs in the same species: Nemegtosaurus mongoliensis.
They are both very similar to Martinez' skull which also, seems to have a
premax-max shelf.

As for Dicraeosaurus......  It is indeed missing most of the central portion
of the face, but its snout is much more like the ones in Diplodocus and
Apatasaurus, as well as the Barosaurus africanus material: very rounded and
without a shelf.

Speaking of Tendaguru sauropod material.... Someone really needs to redescribe
all this skull material, especially Dicraeosaurus and the stuff they have of
Barosaurus and "Gigantosaurus."

 <<Arching nostril is a serious possibility, but I doubt
 it was as large and high as in brachiosaurids and camarasaurids. >>

Maybe, maybe not.  Some combination of Coria and/or Calvo and/or Salgado wrote
this idea up in either Gaia or Amegheniana a few years back.  These journals
are all but non-existant in North America unfortunately, so I am not sure of
the specifics.

Peter Buchholz
Tetanurae@aol.com

-----------------
Janensch, W.  1935.  Die schädel der sauropoden Brachiosaurus, Barosaurus und
Dicreaosaurus aus den Tendaguruschichten Deutsch-Ostafrikas.
Palaeontographica Suppliment 7(1:2):145-248.

Kurzanov, S M and Bannikov, A F.  1983.  A new sauropod from the Upper
Cretaceous of Mongolia.  Paleontological Journal 1983(2):91-97.

Nowinski, A.  1971.  Nemegtosaurus mongoliensis n. gen., n. sp. (Sauropoda)
from the uppermost Cretaceous of Mongolia.  Palaeontologia Polonica 25:57-81.