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R: Spare ribs?



Mickey,
regarding sacral ribs/transverse processes,  you may find of some interest
the drawing of Edmarka's (i think)  sacral bertebrae(fig 3 C-D-E)  in
"Megalosaurid Dinosaurs from the late Jurassic Morrison Formation of eastern
Wyoming", by J.D. Siegwarth and others that can be read online at
www.rjames.com/megalosaur/
While  S1 is depicted as  not bearing any Sacral Rib , but only its
Transverse process, other sacral vertebrae(2-5) have both  ribs and trans.
proc..
>From what I see from the picture(have't read the paper yet, sorry) they're
fused to one another(rib-tran.proc).

In Sinraptor attachment scars  for sacral ribs only are found on the medial
side of ilia( there's no indication of the attachments sites for the
transverse processes);however in Allosaurus there is a clear separation
between the attachmente sites for tr.prs. and  ribs(Madsen pag.147).
Madsen clearly depicted sacral ribs and transverse processes on sacral verts
as separate structures;interestingly the fifth sacral vert. bears a big rib,
while the fifth sac. vert. in Sinraptor  is considered as having a
transverse process, but no rib.
Other sacral verts in Sinraptor are poorly preserved(excluding the first,
almost completely preserved, missing only the caudal portion of centrum ,
neural arch and spine, but bearing a transverse process and no rib, as in
Edmarka but differently form Allosaurus in which a "vestigial"[doesn't seem
to contact the iliumat least ] first sacral rib is present), so it's not
possibile to know what the condition was like in this beast.

Fig. 12-B in the above mentioned reference(Megalosaurid dinos etcetc..)
shows Edmarka's right ilium in medial views so i'm sure that someone with a
more knowledged eye than mine will find  the exact position of instertion of
both sacral strucures.

Hope this helps.
 bye
FC
----- Original Message -----
From: Mickey_Mortimer <Mickey_Mortimer@email.msn.com>
To: <dinosaur@usc.edu>
Sent: Wednesday, February 14, 2001 5:49 AM
Subject: Re: Spare ribs?


Here's what I would like to know- what are sacral and caudal ribs?
> I hear about caudal ribs in relation to diplodocids and some other
> sauropods.  Are these just transverse processes?  Are sacral ribs
transverse
> processes or actual ribs.
>
> Mickey Mortimer
>