jumbo early jurassic long necks was: Re: Apatosaurus vs Brontosaurus

[Cliff Green <dinonaut@emerytelcom.net>]

Dear Ken and List,

    Speaking of which, Dale Russell visited here in Price three weeks ago as
the Keynote speaker for our annual Dinodays weeklong celebration.
    His talk was on Moroccan and Utah Dinosaurs. The one thing that perked
my interest, is that he mentioned Early Jurassic sauropods of truly emmense
size, in Morocco. The French and Moroccan paleontologists found meter wide
footprints, and a 2.3 meter femur,, all from the early Jurassic. They think
that the sauropods are a kind of vulcanodon. They also have complete
skeletons of mid Jurassic brachiosaur ancestors, That Dale did a very good
skeletal ref drawing of, but I don't have the details on it.

Cliff

----- Original Message -----
From: "Ken Carpenter" <KCarpenter@dmns.org>
To: <twilliams_alpha@hotmail.com>; <dinosaur@usc.edu>
Sent: Thursday, May 27, 2004 1:39 PM
Subject: Re: Apatosaurus vs Brontosaurus


> It is alleged that many dinosaurs increase in size stratigraphically in
the Morrison, but the evidence is shaky, especially if you don't consider
large specimens lower in the Morrison.
>
> Kenneth Carpenter, Ph.D.
> Curator of Lower Vertebrate Paleontology &
> Chief Preparator
> Dept. of Earth Sciences
> Denver Museum of Natural History
> 2001 Colorado Blvd.
> Denver, CO 80205
>
> Phone: (303)370-6392
> Fax: (303)331-6492
> email: KCarpenter@DMNS.org
>
> For fun:
>  http://dino.lm.com/artists/display.php?name=Kcarpenter
>
>
> >>> Tim Williams <twilliams_alpha@hotmail.com> 27/May/04 >>>
> Ken Carpenter wrote:
>
> >"The limbs of A. louisae are noticeably more robust than in the other two
> >species [A. ajax and A. excelsus]. Gilmore (1936), p. 268) has also cited
a
> >number of other characters which separated A. louisae from A. excelsus.
As
> >Riggs (1903) has already pointed out, the separation of A. louisae from
A.
> >ajax is more difficult. Based on four speci[mens] of the Tithonian A.
ajax
> >and a half dozen skeletons of the older Kimmeridgian A. excelsus, it is
> >clear that the adult A. ajax is some 10% larger than its geologically
older
> >relative. Size along can hardly justify the separation of species
(McIntosh
> >1990)... For the present it would appear to be prudent to retain A. ajax
> >and A. excelsus." McIntosh, J.S. 1995. Remarks on the North American
> >sauropod Apatosaurus Marsh. Sixth Symposium on Mesozoic Terrestrial
> >Ecosystems and Biota, Short Papers. 119-123.
>
> I wasn't aware of this article - thanks.  I'll try and get a hold of it.
>
> I can understand why it could be tricky to separate _A. ajax_ from _A.
> excelsus_ - after all, how does one distinguish a large _excelsus_ from an
> average-sized _ajax_?  I know _excelsus_ is stratigraphically older than
> _ajax_ (which is roughly contemporary with _Amphicoelias_), and I wonder
if
> there is a gradual increase in the size of _Apatosaurus_ as one goes up
the
> Morrison?  Alternatively, if some exceptionally large _Apatosaurus_
elements
> were found in the Kimmeridgian, it would make the _ajax_/_excelsus_
> distinction very shaky (assuming that they don't belong to _louisae_).
>
>
> Cheers
>
> Tim
>
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