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

----- 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.