Re: Science News etc

["Tim Donovan" <msdonovan66@hotmail.com>]

  It is hard to be sure if the Lancian fauna was really stable. Edmontonia 
may have disappeared hundreds of thousands of years before the end, and few 
large taxa were common. The discovery of very large edmontosaurs and T. rex 
specimens suggests a continuing "arms race". (UCMP 118742 was found 
stratigraphically high). At sea the case for gradual extinction within the 
late Mastrichtian is better.

 Some hypsilophodonts -Atlascopcosaurus IIRC -lived at high latitude and 
were probably capable of hibernating, which meant that shelter was available 
and they could endure a scarcity of food. I doubt any birds were as well 
off. Stidham et al wrote that Neornithines were already proliferating at the 
expense of Enantis in the late Maastrichtian, and diversifying. Under the 
circumstances, survival of several Neornithine lineages is remarkable 
considering their disadvantages compared to certain high latitude dinos, 
under hypothesized impact conditions.

The proliferation of fern species requiring full sun to make spores was 
already underway within weeks of the impact, according to Arens. Such 
species were already more abundant in the upper impact layer than they were 
prior to the impact. Their ability to experience an "ecological release" 
indicates that there was adaquate sun and generally benign conditions.




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