Re: Speculative dino species

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "christian farrell kammerer" <cfkammer@midway.uchicago.edu>
To: "Daniel Bensen" <dbensen@gotnet.net>
Cc: "Dinosaur Mailing list" <dinosaur@usc.edu>
Sent: Sunday, July 29, 2001 8:21 PM
Subject: Re: Speculative dino species


> [...]
> I think a
> question we have to ask ourselves when postulating Cenozoic
> whale-pliosaurs (or mosasaurs) is not whether they _would_ exist without
> mammals, but rather why _didn't_ they exist without mammals
> previously. [...] In any
> case, working on known fossil evidence, it doesn't seem plausible for
> marine reptiles to "go mysticete" in the Cenozoic when, as far as is
> currently known, they didn't in the Mesozoic.

I've read a very simple explanation for this in Carl Zimmer's book At The
Water's Edge: Macroevolution and the Transformation of Life: Baleen whales
evolved when the loop of cold currents closed around Antarctica, which
produced the present enormous amounts of krill. So we should expect
_something_ (something endothermic, according to HPs Paul & Leahy) to become
a giant filter feeder at that time (early Oligocene), but not before.

> (Not that I'm trying to put
> an end to Cenozoic sea-critter speculation, heck, I'm toying with the idea
> of inshore mosasaurs becoming extinct and being replaced by huge,
> estuarine choristoderes, but I'm just presenting some things to think
> about.)

Cool idea. Now just give me a reason to kill off the mosasaurs... :-)