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Re: The Final Days



Original Message by Kashman7@aol.com Sunday, 17. November 2002 05:57 

> > The main problem with the "mega-consumption theory" is, at the end of the
> > end of the cretaceous, their were lots of very small dinosaurs [ie
> > dromaeosaurs, coelurosaurs, troodontids, and other assorted dino-birds].
> > Let alone, some very small herbivorous hypsilophodonts.
> > And these little guys covered the globe, Australia, North America, South
> > America, Asia, Africa, and Antarctica.

Most of these aren't known from the late Maastrichtian, you've certainly read 
enough lamentations on how few terrestrial K-T sites there are. And most 
weren't really small, many would even pass the 25 kg mark (everything above 
that on land is calculated to have died in the earthquake the impact 
produced... but I don't know for which earthquake strength this is 
calculated). http://dinosauricon.com/genera/parksosaurus.html gives 
*Parksosaurus* 2.4 m. The other mentioned ones hardly get below 1.8 m adult 
length. Nonavian dinos as small as *Microraptor* have hardly ever been 
discovered.

> > To tell you the truth, scientists don't exactly know why ALL the
> > non-avian dinosaurs went extinct [Paul 2001].

Obviously. Or we wouldn't need science. :-)

> >                                               Mark Foster
>
> [...] there is some evidence via
> bone growth differences that some of the northern living dinosaurs may have
> been able to accomplish something akin hibernation

Not just the presence of LAGs, I assume?

> the periods of [...] colder temperatures we are talking
> about are probably generations-long or worse.

In case you mean the impact winter, this is unlikely.

> Now:
>
> What were the plant-eaters' specific diets?

Last time you asked such a question you didn't get an answer... because 
nobody knows.

> Did those types of plants survive and if so, where?

The only bigger plant clade that I know of that died out at the K-T is 
Cheirolepidiaceae, the Mesozoic's tropical conifers (if I understood Currie & 
Padian's encyclopedia correctly), which can be found in the Hell Creek Fm. 
http://www.dinosauria.com/jdp/misc/hellcreek.html#plants Apparently 
Nilssoniales was finished too, but apparently nobody knows what that is in 
the first place.

> Did they reappear right after the K/T Boundary or much later?

Angiosperm pollen recovered last, judging from the fern spike paper I cited 
and older information on the Hell Creek Fm.

> Were the dino's forest dwellers, desert dwellers, etc.?

Default assumption is that all dinos were forest dwellers because evidence 
for open land is scarce in most of the world... after all, grass hadn't 
evolved yet... yeah well, the only dinosaur-containing K-T sites that I can 
think of are in the Hell Creek Fm and in the Nanxiong basin; the former was 
forest, the latter... I don't know.

> Were surviving birds, mammals, reptiles, amphibians, etc., initially found
> in few locations or all over the world?

Hard to tell. There are extremely few known terrestrial early Paleocene sites 
in the entire southern hemisphere, for example.

> Were the croc species smaller species that gradually filled the gaps left
> by the disappearance of larger relatives?

We have several croc experts onlist that can probably answer this question... 
assuming anyone can, considering the poor fossil record.

> Are there any exposed locations known that were medium-high
> mountain habitats at the K/T

Certainly not. Should all have been eroded away. The entire mountains, with 
the valleys in between, are gone.

> and might have allowed dinosaurs to have survived past
> the boundary?

Why do you think such places were protected?