Re: B. walkeri neural spines

[Mickey Mortimer <Mickey_Mortimer111@msn.com>]

Steven Coombs wrote-

> I was looking through:
>
> Bailey, Jack, B. Neural Spine Elongation in Dinosaurs: Sailback or
> Buffalo-Backs? Journal of Paleontology, V.71, No. 6, 1997.
>
> And in it I want to know if there is anything more on what Chriag and
Milner
> (1990) reported about the isolated neural spine of B. walkeri, suggesting
> that the dorsal vertebrae were elongated like Spinosaurus but not as big.

According to the complete osteology (Charig and Milner, 1997), that spine
probably belongs to the sacrum.  It's not very long, though a bit longer
than those of the dorsal vertebrae.  Using Bailey's neural spine / centrum
height ratio (his figure 4) as an example, Baryonyx's eleventh dorsal neural
spine (the highest preserved) would rate 1.9.  This, compared to
Spinosaurus' 10.8.  Ratios in "normal" theropods can be almost as high-
Allosaurus (1.6), Tarbosaurus (1.6), Gallimimus (1.1), Deinonychus (1.0).
So Baryonyx did not have particularly elongate dorsal neural spines,
certainly nothing comparable to Spinosaurus or even Acrocanthosaurus.

Mickey Mortimer
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html