Re: Late Cretaceous Giant Ceratopsians and Hadrosaurs

[Vladimír Socha <Seismosaurus@seznam.cz>]

================= Original message =================
From: "Vlad Petnicki" <bucketfoot-al@justice.com>
To: Seismosaurus@seznam.cz
Copy (Cc): dinosaur@usc.edu
Subject: Late Cretaceous Giant Ceratopsians and Hadrosaurs
Date: 17. 2. 2004 17:26
==================================================

< Vlad, if you think about it - it makes sense from an
< ecosystem point of view.
< 
< We know that the really large dinosaurs - the sauropods
< - had disappeared from Western North America by the
< mid-Cretaceous, as the conditions changed and animals
< got smaller.  They did not reappear until just at the
< end, when Alamosaurus apparently migrated over a new
< land bridge to South America, and made it as far as
< Texas before the mass extinction.
< 
< As the Cretaceous drew to a close, climactic conditions
< in Western N. America changed to once again favor large
< size - hence the ascent of the T-Rex, Triceratops,
< Torosaurus, Anatotitan, etc.
< 
< Now, since the "giant" niche was lacking the suropods,
< does it not make sense that some other species
< (Hadrosaurids or Ceratopsians) would have "stepped up
< to the plate" (an American baseball expression) to fill
< it?
< 
< Just some food for thought.  Other than the footprints,
< I am not exactly sure what the fossil record shows of
< the supposedly giant Hadrosaurids;  however, the giant
< Triceratops neck found by Barnum Brown, as well as the
< Trice. skull at BYU tell us that this species could get
< much larger than previously thought.

OK, I don't have a problem with "large" Hadrosaurids, measuring up to, say, 17 
m (+-8 tonnes), but they were differently built than massive sauropods. A 
hadrosaur (though quadruped) could never reach mass over 20 or even 30 tonnes! 
Its legs would then need to be as thick as a tree trunk, which is possible in 
large sauropods but not ornithischians and theropods. No problem with giant 
Triceratops at all. Vladimir "Micropachycephalosaurus" Socha

  

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