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Re: Arboreals dinos, handedness, what people sez etc.




From: Jerzy Dyczkowski <jerzyd@poczta.ibb.waw.pl>
Reply-To: jerzyd@poczta.ibb.waw.pl
To: <StephanPickering@cs.com>
CC: <dinosaur@usc.edu>
Subject: Arboreals dinos, handedness, what people sez etc.
Date: Thu, 31 Jan 2002 13:44:41 +0100 (CET)


In modern ecosystems, there is well developed group of bigger arboreal
animals. This includes herbivorous and frugivorous primates, squirrels and
some procyonids, bears, marsupials and hyraxes; and predatory marsupials,
cats, martens and viverrids.

Was this ecological niche empty in Mesosoic and why? I understand, that
early restorations of arboreal hipsylophodonts were abandoned and only
arboreal mesosoic animals were birds, probably pterosaurs and small
animals.

About other topics:

Raising body temperature to warm eggs exists in modern reptiles (e.g.
pythons) and insects. Does not seem to lead to all-time endothermy.

you wouldn't want it to, especially if you were a phython, would be far too metabolically expensive. I doubt the body shape of snakes (SA/Volume ratio) is compatible with full endothermy. (especially with their rather inefficient prey capture methods.


Flight in bats probably evolved by jumping up or hopping down the rocks
catching insects with front paws (modern bats use wing membrane to catch
insects).


I think more the patagial membrane between the hindlegs.


Plumage of birds rather hinders the egg warming, than helps it (therefore
most birds develop bare brood patches).

Hopping down the trees from nest is not usual in modern birds, who
generaly leave the nest as inconspiciously as possible.

Most basal modern birds (Galloanserae and ratites) are mostly ground
nesters and do not feed their young.


"Handedness" can be seen in elephants and mammoths, because one tusk is
always more worn. Something similar might probably be seen in dinosaur
horns or claws. It is worth to remember once more, that bodies of all
animals are never completely symmetrical anyway.

Hope it is enough to keep you all occupied for some time,

Jerzy





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