Re: Mesozoic - the heyday of life?

[Jonathon Woolf <jwoolf@erinet.com>]

GSP1954@aol.com wrote:
> 
> The observation that vulcanodonts were not large is incorrect. My approximate
> mass estimate is 5 tonnes, about the same as a typical bull elephant. The
> rapidity at which sauropods increased size is remarkable. 5 tonnes at the
> very beginnning of the Jurassic, 10 tonnes later in the Early Jurassic, 30
> tonnes in the Middle Jurassic, 50-100+ tonnes by the Late Jurassic all the
> way to the end of the Cretaceous. No land mammals have even touched that
> record.

<groan>

<minor-irritation mode ON>

I never said vulcanodonts were small, people.  I said vulcanodonts were
not especially large WHEN COMPARED TO THE LARGEST KNOWN MAMMALS.  David
Portree had posted a message saying in part that 

> seems to
> me that, in many ways, life on Earth took a downturn after the Mesozoic.
> Animals now are generally smaller. Some would argue they're slower, too. They
> don't have as big and varied an arsenal of weaponry, offensive and defensive,
> as did the dinosaurs.

I simply wanted to point out that a) it took dinosaurs a very long time
to produce any really _giant_ species, and b) mammals have produced some
pretty damned big species too, in less time than it took dinosaurs to do
it. Dinosaurs took sixty million years to evolve from wolf-size
predators to ten-ton sauropods.  Mammals took only forty million to go
from cat-size predators to twenty-ton indricotheres.  I thought that it
would be clear from the context that by "giant" dinosaurs, I meant
diplodocids, brachiosaurs, and others of similar scale: those that
exceeded ten tons or so in mass and/or ten meters in length.  

That's all I said; that's all I meant.  I never said nor implied that
vulcanodonts were small on any sort of absolute scale.  I'm well aware
that I don't know as much about dinosaurs as some people here, but I
resent getting my chops busted over an error that is not on my end of
the communications link.  

<minor-irritation mode OFF>

-- JSW