Re: SUCHOMIMUS STUFF

[Jim Kirkland <dis@gj.net>]

Thomas R. Holtz, Jr. wrote:

> II) Ecology
> It is true that grizzlies only eat salmon during the salmon run season.  It
> is also trye that this is the only season in which large fish exist at
> sufficient quantaties in the streams of the American Northwest.
> 
> The paleoenvironments from which known spinosaurids come all support diverse
> communities of fish, some of which were very large.  There is currently no
> evidence that these were seasonal communities, and would seem likely to be
> permanent residents.  Thus, we have very large packages of fish meat not
> otherwise easily exploitable by theropods.  

Baryonx was associated with Lepidotes (a big fish) scales. My research
on the freshwater fish in the Cretaceous of western North America
incates that Lepidotes was very common in Cenomanian river systems well
inland. The response I got was that Lepidotes was known from marine
rocks so it is a marine fish. My data suggests that perhaps some large
species were like Salmon and went up rivers to reproduce. THUS,
seasonally perhaps Lepidotes was present in very large numbers and was
thus a food resource not to be ignored.
        Also of interest is that this group goes extinct at the end of the
Cenomanian, when Spinosaurids disappear. Even in the Late Cenomanian
these fish are very abundant, but there is not a sign in the Turonian.
This is a big extinction level for fresh water fish in North America
(see Eaton et al. GSA Bull. 109(5):560-567, 1997).

Jim Kirkland