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RE: Hopping Hadrosaurs



Yes, important as usual to RTFA; the study didn't fail to find any reason
(other than plausibility, which is not useless) for why hadrosaurs probably
didn't hop or gallop. They found that bone stresses were ~2x as high in
those behaviours vs. more plausible ones like bipedal running, and would
probably broken the bones.

-John


> -----Original Message-----
> From: Justin Tweet [mailto:thescelosaurus@juno.com]
> Sent: 13 December 2009 23:49
> To: dinosaur@usc.edu
> Subject: Re: Hopping Hadrosaurs
> 
> [sending out url again because my sig tag got incorporated into it]
> 
> http://palaeo-electronica.org/2009_3/180/index.html
> 
> -Justin
> 
> 
> ---------- Original Message ----------
> From: "Justin Tweet" <thescelosaurus@juno.com>
> To: dinosaur@usc.edu
> Subject: Re: Hopping Hadrosaurs
> Date: Sun, 13 Dec 2009 23:39:16 GMT
> 
> Chalk up one for overenthusiastic reporting:
> 
> The article about hadrosaur locomotion is in the most recent
Palaeontologia
> Electronica.  The authors acknowledge they got the greatest speeds from
> hopping, but consider it an unlikely mode of locomotion and more likely
> something that's not being properly accounted for in the model.
> 
> Sellers, W. I.; Manning, P. L.; Lyson, T.; Stevens, K.; and Margetts, L.
> (2009). "Virtual palaeontology: gait reconstruction of extinct vertebrates
> using high performance computing". Palaeontologia Electronica 12
(3):article
> 13a.
> http://palaeo-electronica.org/2009_3/180/index.html.-Justin
> 
> 
> 
> ---------- Original Message ----------
> From: Dann Pigdon <dannj@alphalink.com.au>
> To: dinosaur@usc.edu
> Subject: Re: Hopping Hadrosaurs
> Date: Mon, 14 Dec 2009 08:48:23 +1100
> 
> On Mon, Dec 14th, 2009 at 8:33 AM, Augusto Haro <augustoharo@gmail.com>
> wrote:
> 
> > It has been said that glyptodonts jumped bipedally in certain
> > biomechanical studies, so I would not be surprised many tetrapods can
> > be considered as a jumpers based on biomechanical data....
> 
> Unfortunately 'biomechanical data' and 'reality' frequently part company.
A
> computer model is only
> as good as it's been told to be (by a fallible human programmer).
> 
> Although modern analogues may not encompass the gamet of past biological
> forms, at least
> they're observable. When kangaroos hop, they not only have specialisations
> in the hindlimbs that
> improve energy efficiency, but their tail acts like a mobile stabiliser
> throughout the gait cycle.
> Hadrosauir tails were likely too stiff to act as macropod-like flexible
> stabilisers. When you're trying
> to out-run (or out-hop) a large theropod, instability is generally not a
> good thing.
> 
> > > On Fri, Dec 11th, 2009 at 5:04 AM, Danvarner@aol.com wrote:
> > >
> > >>
> > >
>
http://www.manchestereveningnews.co.uk/news/s/1185658_when_dinosaurs_hopped_
> the_earth
> > >
> > > Firstly - the subject line would have been greatly improved with the
> addition of the word
> > 'Batman'
> > > at the end. :-)
> > >
> > > Secondly - macropods show a whole suite of specialised hindlimb
> adaptations for hopping, and
> > > were a tiny fraction of the mass of an adult hadrosaur. Yet apparently
> hadrosaurs could
> manage
> > a
> > > similar gait even though they lack such hindlimb adaptations. Colour
me
> skeptical on this one.
> > >
> > > --
> > > _____________________________________________________________
> > >
> > > Dann Pigdon
> > > GIS / Archaeologist                Australian Dinosaurs
> > > Melbourne, Australia               http://home.alphalink.com.au/~dannj
> > > _____________________________________________________________
> > >
> > >
> >
> >
> >
> 
> 
> --
> _____________________________________________________________
> 
> Dann Pigdon
> GIS / Archaeologist                Australian Dinosaurs
> Melbourne, Australia               http://home.alphalink.com.au/~dannj
> _____________________________________________________________