RE: Documentaries & Sabertooths

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

> Are there any records of Mesozoic animals adapted for eating shellfish? 
> Placodonts from the Triassic and the weird mosasaur Globidens fit the
> bill, but what about the periods in between?

Several groups of Jurassic and Cretaceous tetrapods had jaws and/or teeth
designed for crushing shellfish - though not always the same types of
shellfish.  They include: Mosasaurs (_Globidens_, _Igdamanosaurus_, certain
plioplatecarpines), ichthyosaurs (remember that vomit? [or was it vomit? -
see Ray Stanford's comments on the DML]), possibly even an amphibious
Mesozoic mammal (_Kollikodon_).

> And what about plankton feeders? 

The comb-jawed pterosaur _Pterodaustro_ might have been an aerial
plankton-feeder.

Quite possibly there were plankton-feeding sharks in the Cretaceous, as they
are today.  The earliest evidence of cetorhinids (basking sharks) and
rhincodontids (whale sharks) is a gill raker and teeth (_Palaeorhincodon_),
respectively, of Eocene age. 

I would also add that modern fishes and sharks will occasionally feed on
plankton by simply lunging at plankton concentrations - without having the
benefit of equipment to strain them out.  Maybe sea-reptiles did the same.



Tim


----------------------------------------------------------- 




Timothy J. Williams, Ph.D. 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 9359