Re: Hopping Hadrosaurs

["Justin Tweet" <thescelosaurus@juno.com>]

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
_____________________________________________________________