Re: Ceratopsian Forelimb Articulation

[Michael Teuton <tons@ccs.logicsouth.com>]

Allan Edels wrote:

> All:
>
>     Sometime in the last few months, someone asked about ceratopsian
> forelimbs - Were they fully-errct or did they have a sprawl to them?
> Several people (myself, Tracy Ford and others) indicated that there was
> slight sprawl to the forelimbs - with the elbows bent out.
>
>     I based my opinion on a particular mount (_Chasmosaurus belli_  at
> ANSP), which I knew had been designed to show the ceratopsian as an agile,
> fully-erect dinosaur (Ken Carpenter designed and built it).  The forelimbs
> show a slight sprawl, as it became evident that without the sprawl, the
> _Chasmosaur_ would constantly bang it's elbows into it's ribs (and the bones
> don't show evidence of such).  (The humerus has a large inward-directed
> flange on the proximal end of it
>
>     Tracy indicated that Protoceratopsian specimens DO allow for the
> fully-erect posture in the forelimbs.
>
>     Someone else was disappointed that there was no references to back up
> what are merely personal observations.  I have found one:"The Forelimb
> Carriage of Ceratopsid Dinosaurs" by Peter Dodson and James Farlow, in
> "DinoFest International: Proceedings of a Symposium Held at Arizona State
> University" pp.393-398.
>
>     => "....Paul's (1991b) reconstruction of _Triceratops_ shows slight
> inward angling of the lower bones of both the foreleg and hindleg.  If there
> was more such inward angling of the lower foreleg than the lower hindleg (as
> in the American Museum's _Triceratops_ mount - Figure 5), a larger outward
> angling of the humerus than 10-20 degrees becomes possible.  In order for
> the big internal flange of the proximal end of the humerus to have cleared
> the ribcage, we estimate that the humerus would have needed to angle roughly
> 30 degrees outward from the vertical.
> ...."
>
>     (Please note that the authors used both skeletal and trackway evidence
> to come to their conclusions).
>
>     Hope this helps whoever had any more questions.
>
>         Allan Edels

Are there any large land based extant animals that have a sprawling forelimb?

Michael Teuton