sauropod resume

[Sebastian Apesteguia <sebapesteguia@yahoo.com.ar>]

By the way, some people told me that didn't received
the previous messages because I had a rich text format
(now corrected I think), so here is a short resume:

T:
Dalla Vecchia considered _Histriasaurus_ from Croatia
to be a 
rebbachisaurid. Apesteguia (2005) considers this
unlikely, based upon the 
presence of a hyposphene-hypantrum complex in the
dorsal vertebra (absent 
from other other rebbachisaurids). Apparently he has a
paper in press.

S:
hey, hey Tim, I didn't said exactly that. Of course
the beauty hyposphenes of Histriasaurus are
plesiomorphic for rebbs, but this is not enough to
exclude it totally from rebbs (those devoid of a
single plesiomorphy, feel free to throw the firt
stone!). All the best. Sebastian.

N: telling me the text was corrupted.
S:
hiNick, I only responded to Tim saying that I didn't
said exactly that Histriass is not a rebb. That its
beauty hyposphenes are plesiomorphic for rebbs, but
this is not enough to exclude it totally from the
group (those devoid of a single 
plesiomorphy, feel free to throw the firt stone!).
About sauropods yes, I think they have muchmore to say
by now. After Bonita, igerss and Brachytrachelopan,
nothing will be the same for these guys.
I hope this reach you cause I am right now at north
Patagonia and the internet service here is far from
good. All the best. Sebastian

N: 
I got your message, but what is Brachytrachelopan? I
have not heard of it. I admit I am not to the familiar
with sauropods. :(((

S:
Brachtrachelopan is a gorgeous dicraeosaurid from
Chubut (Central Patagonia) described by Rauhut which
has a short neck and forward-directed neck spikes, I
don't know, but I think Cretaceous South American
sauropods (as I said in the last SVP meeting) are
using some of the ecological zones commonly occupied
by ornithischians in other places.

N:
Ooooh! I think I have this paper. But I am curious,
what of
ornithischians in southern hemisphere, I know of a few
like
Secernosaurus, Gasparinisaura, Talenkauen, etc. surely
they are not
totally absent.

S:
no, of course they are present. We have them since
Triassic,along Jurassic footprints, early Cret
stegosaurs, and the Muttaburra and Minmi at Australia,
a "mid" Cretaceous silence (except for the huge
Calvo's tracks from El Chocon) and a Late Cretacous
"diversity" of small to mid sized iguanodontians like
Gasparinisaura, Anabisetia, Notohypsilophodon.
Finally, by Lateset Cret, we have the iguanodont
Talenkauen, several hadros (northern invaders?) and
some ankylosaurs. As you can see, ornithischians are
present, but just compare this with northern
hemisphere. Record bias? I don't think so. Sebas

M:
Well, there are several localities which have yielded
hadrosaurid remains in Argentina, including
undescribed hadrosaurines and lambeosaurines, but
these advances have been published in local
congresses. All the best, Matías Soto

S:
yes, Matias, but up to now, hadros (and lambs) (IF
THEY ARE) come only from Late Campanian-Early
Maastrichtian units, which is consistent with the
Bonaparte's biogeographic proposal and the arrival of
Gw taxa (IF THEY ARE) to North America. Recent
findings of putative hadros in earlier units have not
been confirmed, and they could be easily big
iguanodonts.


Lic. Sebastian Apesteguia
Seccion Paleontologia de Vertebrados
Museo Argentino de Ciencias Naturales 'B. Rivadavia'
Buenos Aires, ARGENTINA
www.paleoninjapesteguia.com.ar


        

        
                
___________________________________________________________ 
1GB gratis, Antivirus y Antispam 
Correo Yahoo!, el mejor correo web del mundo 
http://correo.yahoo.com.ar