flexible horizontal ridge in dino restorations...

[Luis Oscar Romero <legolas@abaconet.com.ar>]

On Tue, 07 Oct 1997 17:12:35 wa105@mead.anglia.ac.uk wrote:

<<I remember seeing in a few dinosaur pictures (I'm afraid I can't cite
any specific ones) a horizontal ridge running from shoulder to hip.  I
have a jigsaw with a sauropod showing one of these very clearly.  It
goes wavy when the foreleg is pointing back and the hindleg forward, so
it must be flexible but not stretchy.

What is this?  A tendon?  A fold of skin, like the vertical ones in
Asian rhinos?  A seriously vulnerable major vein?  What is the evidence
for the existence of this structure? I cannot think of any living
animals with a prominent line in this position.>>

I've seen this ridge in most of John Sibbick's sauropods, and in at
least one of Greg Paul´s drawings (Tarbosaurus vs. Therizinosaurus,
1988).

In extant animals, this ridge is visible in varanids and maybe some
lizards. A picture of a Komodo Dragon in the Encarta Atlas  shows two
parallel ridges, although they don't reach all the way to the hind
quarters and they are not very well marked.

They look like folds of skin to me, so they would be more visible when
the animal is undernourished, and less when it's belly is full.

Since lizards and more particularly Komodo Dragons had been used as
dinos in many low budget "prehistoric" films back when most of us were
kids, I think this has influenced artists to depict dino skins with this
fold  ;), or more likely, that the artist has used living animals of
similar caracteristics (i.e. reptiles) as reference.

Oscar Romero