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

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

----- Original Message -----
From: "Raptorial Talon" <raptorialtalon@gmail.com>
Sent: Monday, March 30, 2009 9:57 PM

> The other plausible option in my mind is simply that a particular food
> source, one promoting specialization, was so comparatively abundant
> that it was just waiting for a predator to tap into specifically. In
> apparently theropod-rich, herbivore-poor environments like those of
> *Spinosaurus*, and that would appear to be fish (and other aquatic
> targets) - even if they were only seasonally available. A sufficiently
> rich harvest of fish each year, providing vital fats and protein to
> survive the next hard season, could perhaps prompt a degree of
> specialization. Of course I'm not sure that would really be true for
> all spinosaurs in various other habitats, but maybe that set of
> conditions was the locus of their evolution.

AFAIK *Spinosaurus* did not live in a habitat with seasons. The weather 
wasn't the same all year round, but the storms were convective, not a 
monsoon or something. The idea is that it was _so_ hot in and around the 
Cenomanian that the intertropical convergence zone became too broad to 
function the way it does today. There was a paper in Cretaceous Research in, 
I think, 2001 that I have extensively quoted onlist.

I'm not aware of lake sediments or indicators of aridity from the Aptian to 
Cenomanian sediments of the Sahara. I have trouble imagining a 
several-meter-long lungfish digging a burrow, let alone a coelacanth of the 
same size. No, it looks like the Aptian to Cenomanian Sahara was productive 
enough to support sauropods of all sizes (*Nigersaurus*, *Paralititan* -- as 
a feeder on ground vegetation, *N.* needed fairly frequent rain; it was 
capable of following the rain around, but...), large ornithopods 
(*Lurdusaurus*), a diversity of enormous theropods, and last but not least 
Supercroc.