Ankle manipulation (Was Re: "Heel to Toe")

["Martin Barnett" <martin.barnett3@virgin.net>]

As Ray stanford has mentioned Pterosaurs I felt I was safe to bring up the
subject of dogs briefly (don't worry - I'm still on dinos, not really
unrelated)  I have often noticed with dog hind-limbs that the angle between
the tarsus and the tibia is generally relative to the angle of the femur to
the tibia in it's stages of leg bending.  Therefore the knee and ankle
movements are related in their crouching cycle.  Would the same be true of
dinosaurs?  How does the lack of a heel process alter this situation?  Could
a dinosaur have had a straight knee and an angled heel at the same time as
we do?

Sam

----- Original Message -----
From: Ray Stanford <dinotracker@earthlink.net>
To: <edels@email.msn.com>; <mickey_mortimer@email.msn.com>;
<dinosaur@usc.edu>
Sent: Wednesday, February 02, 2000 10:48 AM
Subject: Re: "Heel to Toe"


> Hi Allan Edels, Mickey Mortimer, Matthew Bonnan and list,
>
>     Thanks for each of your observations and comments.
>
>     Allan Edels said, "However, the official definition of dinosaurs
> includes the digitigrade stance (ref. "Dinosauria" Dodson, etc.).  Of
> course, the definition is based on the skeletal features".  [Ray's note:
> i.e., NOT upon trackway evidence, which I think might well be considered
in
> overview.]
>
>     Thanks for that reference, Allan.   Your meaning is clear in using the
> term "official", yet in terms of science, which changes across time, I
> prefer "tentatively 'official". :)  All kidding aside, Matthew Bonnan has
> just given us his as-always-excellent explanation, and now I'm wondering
> whether he might agree that not all dinosaurs are OBLIGATE digitigrade
> walkers (in view of the trackway record).  [ O.K., maybe that should be
> called 'special case' walking, but the ball is in your court, Matt.]
>
>     In the context of digitigrade dinos, the uninitiated could remember it
> by singing (along with "Tiny Tim" and his ukalele of 1950's Ed Sullivan
Show
> fame), "[Dinos] TIP TOED through the tulips...la de da da...de de
doedo..."
> ;)
>
>     But, still I sometimes wonder how thoroughly "digitigrade" is or is
not
> defined, or whether there are degrees of it.  All things in nature are not
> always accurately described as purely black or white.
>
>     That said, is anyone game for a discussion on, "How did pterosaurs do
> it?" ;)   Oops!  That's not dinos!  But at least THEY progressed
> terrestrially with the pes PLANTIGRADE  (during quadrapedal motion),
> according to recent papers (references available upon private request).
As
> to how the did the OTHER thing? Huuummm...
>
>     Digitigradially, ;),
>
>     Ray Stanford
>