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Re: Berlin Brachiosaurus



Mark Hallett writes:
 > A nice short article, but where did the author get the
 > pronouncement that brachiosaurids couldn't swim? 

My best guess would be that this idea comes from the observation that
the _B. brancai_ holotype HMN SII was found in an unusual position,
its legs vertical, indiating that it died when it became mired.

Dann Pigdon writes:
 > A paper a few years ago attempted to look at brachiosaur bouyancy,
 > and concluded that their relatively narrow bodies and their
 > top-heaviness may have made them too unstable (and prone to
 > capsizing) for them to swim in open water.

Actually, there were two independent studies on sauropod buoyancy,
which happened to come out very close together:

        Henderson, Donald M.  2003.  Tipsy punters: sauropod
        dinosaur pneumaticity, bouyancy and aquatic habits.
        Proceedings of the Royal Society of London, B
        (Supplement) 271: 180-183.  DOI
        10.10998/rsbl.2003.01.36

        Wilson, Jeffrey A, and Daniel Fisher. 2003.  Are
        manus-only sauropod trackways evidence of swimming,
        sinking, or wading?  Journal of Vertebrate
        Paleontology 23(3): 111A.

Of these, Wilson and Fisher's work is still available only as that
abstract, so far as I know.  Henderson's abstract in the same volume
("Sauropod dinosaurs were the colossal corks of the Mesozoic") is
superseded by the Proc. B paper.

By the way, I've always been puzzled by Henderson's conclusion that
floating sauropods would be unstable, since all the pneumatic
structures are concentrated along the (dorsally positioned) axial
skeleton while the appendicular skeleton is good and solid.  Naively,
they look to be perfectly built for stability in water.

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor    <mike@indexdata.com>    http://www.miketaylor.org.uk
)_v__/\  If two decades of commercial programming have taught me anything,
         it's NEVER to trust dual CPUs, "uninterruptible" power supplies
         or RAID disks.