Re: Mysticete evolution (was Re: Speculative dino species)

[christian farrell kammerer <cfkammer@midway.uchicago.edu>]

On Tue, 31 Jul 2001, Graydon wrote: 
> Well, *could* aquatic reptiles evole a strainer?  Baleen is modified
> hair, rather than modified teeth; I don't know what whale sharks use,
> but they do have the advantage of continuous water flow to work with.
> 
> Perhaps there just wasn't anything to exapt into the filter.

The "strainer" isn't the problem, after all, Pterodaustro and the
ctenochasmatids are proof positive that teeth can do just fine as
something to form a filter. The problem is whether or not the pharyngeal
structure of marine reptiles was able to form the "seal the mouth and push
out the water" feeding strategy of filter-feeding mammals. The giant
planktivorous fish get around this since they have gills to
redirect the water, but it would be problematic for reptiles unless they
could somehow squeeze out the massive amounts of water they would have to
routinely take into the oral cavity.

-Christian Kammerer