Re: Sauropterygian falls?

[Tim Williams <twilliams_alpha@hotmail.com>]

Daniel Arndt wrote:

> That's a very good question. Another interesting fact about some
> Ichthyosaurs, specifically _Shonisaurus_, is that the adults are 
> edentulous.
> So some suggest that they may have been similar to rorqual whales, as the
> hyoid apparatus in this specimen measured nearly 5 feet long.

Thanks for the ref.  Nicholls and Manabe (2004) argue that many ichthyosaurs 
were edentulous as adults. The authors favor _Shonisaurus_ being a suction 
feeder rather than a filter feeder, and suggest that belemnites and squid 
were sucked up by the jaws.  Thus, modern beaked whales (Ziphiidae) are 
cited as the closest analog to toothless ichthyosaurs.  (I believe that 
sperm whales are also thought to use suction to gobble up giant squid.)

By this time (Late Triassic) there is evidence of filter-feeding sharks 
(e.g., _Pseudocetorhinus_), so the large-bodied filter-feeding niche 
apparently didn't go begging.

> Also, this find is dated to be Norian (Late Triassic) in age, so 
> Ichthyosaurs got really big, really fast.

Just like sauropods!


Cheers

Tim