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Re: Terrestriality is a bias




... and so is Arboreality.

What needs to be done is to stop Pigeon hole nature into arboreality,
but nature will prove us wrong.
There has been a recent study on island endemic lizards (I didn?
t copy the article but I know the series that it was in. I wish I had copied
it.) showed that terrestrial and arboreal lizards of the same genus (?, or
was it species?) did not show any skeletal differences. If it was found in a
quarry it would have been interpreted as being terrestrial. Komodo monitors
will climb trees until it reaches a length of 6 feet. They also show
arboreality in their skeletons. Bears climb, a certain goat can climb trees,
dogs, squirrels, etc, but their skeletons don?t show this. What about the
pelycosaurs _Varanosaurus_ and _Aerosaurus_? They are about the size of a
small Komodo monitor, could they climb trees?

These are anecdotes. They do nothing to show that certain theropods were/were not arboreal. All this suggests is that certain rare behaviors in bears, goats, etc., are not necessarily predictable from a quick and cursory observation of their skeletons alone. But would you argue that bears are arboreal because they can, in certain exceptional instances, climb into trees?


Could pelycosaurs climb trees? Well, maybe, but how often would they be there and for what advantage? Furthermore, even though Komodo dragons may climb up trees and other foliage, would you argue they were arboreal? What does the joint and limb structure of a Komodo dragon look like, and how does that skeleton allow occasional arboreality? Have these characteristics been noted in pelycosaurs? Are the enivornments the pelycosaurs lived in and the Komodo dragon lives in similar? Since pelycosaurs are synapsids, is it fair to compare them with a large diapsid lepidosaur? Just because some pelycosaurs are the size of a small Komodo dragon or varanid lizard does little to show possible tree-climbing behavior.

With theropods there is a terrestrial bias, and placing a
theropod in a tree gets laughed at. I?ll admit that I was one who laughed at
the idea.

This again has little to do with whether an animal could be shown, through empirical evidence, to be arboreal.


Greg Paul had put on _Ornitholestes_ in a tree and I thought yea
right. But maybe he?s right. I?ll have to look at it more closely. What
about dromaeosaurids? Could they have climbed trees? This is something I?m
working on and a few others.

Would like to see the work -- could be interesting.

Will that be accepted? Probably not. A
_Deinonychus_ is bigger than a Komodo monitor but would have been lighter.

How are you determining the mass of a living Deinonychus? Even if it was lighter, how does that show us that it was regularly an arboreal animal, spending much of its time in the trees?


Why must theropods be put through a more rigorous testing than other
animals?  Terrestrial bias is why.

Forget about bias. Rather, examine your own bias toward arboreal theropods. What is compelling you to decide they are arboreal? If the majority of paleontologists are being led blindly toward terrestrial theropods, then, dammit, show us what you have. Do you have something interesting we should know about the joint structure? Have there been studies examining theropod remains and their taphonomy and sedimentology that suggests they are dying in forested areas? If you are not correct, what ev
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