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Re: Agustinia ligabuei



I thought (when I first saw the paper) that some of the longer ones may 
actually be ribs, for instance the ones in figures 4 and 5 especially 
(Bonaparte,1999), but the elements in figures 3 A and B do not look like ribs 
at all or sacral elements, and look like probable osteoderms (although the fig. 
3 B element now vaguely reminds me of a pair of ilia viewed ventrally).

Until actual photos are published and the specimen is redescribed I think it is 
hard to be sure. I think a histological analysis might be appropriate as well.



----- Original Message -----
> From: Stephen Poropat <stephenfporopat@gmail.com>
> To: Dinosaur Mailing List <dinosaur@usc.edu>
> Cc: 
> Sent: Wednesday, May 23, 2012 8:57 AM
> Subject: Agustinia ligabuei
> 
> Hi all,
> 
> I'm going to ask a potentially very silly question: how certain can we
> be that the osteoderms (particularly types 3 and 4) of *Agustinia
> ligabuei* Bonaparte, 1999 are actually osteoderms? Is it possible that
> they are just misidentified transverse processes / sacral ribs
> (compare the base of the osteoderm (but rotate it upside down) in
> Bonaparte (1999) to Figure 23.B in Curry Rogers (2009), for example)?
> If so, then the sacrum would have to have been at least a third wider
> than it is long (though I don't 100% trust the scale bars for the
> dimensions of the sacral vertebrae - in Bonaparte (1999), Figure 1
> suggests that they are ~11cm long, whilst Figure 2 suggests ~67cm...).
> Novas (2009) follows Bonaparte's (1999) Figure 2, and based on his
> Figure 5.4 (p. 173; presuming his scaling of the osteoderms is
> correct) the breadth of the pelvis (without the ilia) would be ~91cm.
> 
> The identity of the Type 2 osteoderm (640mm transverse length) is a
> bit more problematic; could it be the fused ischia, viewed dorsally?
> Similarly problematic is the type 4 osteoderm in Figure 5 of Bonaparte
> (1999) which was 760mm long; could this be a dorsal rib?
> 
> The only images I am able to find of the holotype specimens are those
> in the original paper and the re
algado & Bonaparte (2007) and Upchurch et al. (2004)
> don't add much to the original description, the codings for
> *Augustinia* [sic] in Curry Rogers 2005 appear not to actually
> correspond to *Agustinia*, and I've had no luck finding any images on
> the internet. Have I missed any important references to this specimen?
> Do any photos and / or a quarry map exist somewhere, I wonder?
> 
> If I'm completely off the track here, please let me know, it's just
> that I've been looking at Bonaparte's figures and struggling to
> believe the interpretation. This taxon is definitely in need of
> redescription and re-illustration... or (wishfully thinking) another,
> more complete specimen!
> 
> Cheers,
> 
> Steve
> 
> Bonaparte, J.F., 1999. An armoured sauropod from the Aptian of
> northern Patagonia, Argentina, In: Tomida, Y., Rich, T.H.,
> Vickers-Rich, P. (Eds.), Second Gondwanan Dinosaur Symposium: National
> Science Museum Monograph, 15, Tokyo, pp. 1-12.
> Curry Rogers, K.A., 2005. Titanosauria: a phylogenetic overview, In:
> Curry Rogers, K.A., Wilson, J.A. (Eds.), The Sauropods: Evolution and
> Paleobiology. University of California Press, Berkeley, pp. 50-103.
> Curry Rogers, K., 2009. The postcranial osteology of *Rapetosaurus
> krausei* (Sauropoda: Titanosauria) from the Late Cretaceous of
> Madagascar. Journal of Vertebrate Paleontology 29, 1046-1086.
> Novas, F.E., 2009. Cretaceous sauropods, In: Novas, F.E. (Ed.), The
> Age of Dinosaurs in South America. Indiana University Press,
> Bloomington, pp. 166-241.
> Salgado, L., Bonaparte, J.F., 2007. Sauropodomorpha, In: Gasparini,
> Z., Salgado, L., Coria, R.A. (Eds.), Patagonian Mesozoic Reptiles.
> Indiana University Press, Bloomington, pp. 188-228.
> Upchurch, P., Barrett, P.M., Dodson, P., 2004. Sauropoda, In:
> Weishampel, D.B., Dodson, P., Osmólska, H. (Eds.), The Dinosauria:
> Second Edition. University of California Press, Berkeley, pp. 259-322.
> 
> --
> Dr. Stephen Poropat
> 
> Postdoctoral Research Fellow
> Uppsala University
> Villavägen 16
> SE-752
rch Associate
> Australian Age of Dinosaurs
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>