Re: Size of *Neoceratodus africanus* and/or *N. tuberculatus*

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Christophe Hendrickx" <nekarius@hotmail.com>
Sent: Sunday, March 29, 2009 8:32 PM

> When I gave a talk on Spinosauridae, someone told me that the very 
> elongated
> neural spines could support a hump of fat which could help Spinosaurus 
> floating
> into the water. Again, it is a new (but quite interesting) speculation 
> therefore, in conclusion, we should wait new
> discoveries about the anatomy of Spinosaurus (and Spinosauridae) that 
> could help us to interpret
> the living habit of this dinosaur before proposing many hypotheses that no 
> one can demonstrate.

Also, why would an animal with an air-sac system need such an adaptation to 
float?

In my opinion, the elongated neural spines of *Spinosaurus* are much too 
tall and much too numerous to have (at least in their entirety) supported a 
hump composed of fat. A muscular hump -- at the very least one of anywhere 
near that size -- would simply have been useless. We will have to look for a 
function in sexual selection or -- maybe -- a thermoregulatory one that the 
smaller *Baryonyx* and apparently the similar-sized *Carcharodontosaurus* 
somehow didn't need.