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Re: Permian protofeathers???
Sure, I can see baby Eoraptors using their protofeathered tails for
predator evasion (even against bigger Eoraptors), and the same tail could be
used by adult male Eoraptors to attract mates. But what makes such
discussions even more difficult is the controversy over whether Eoraptor and
herrerasaurids are cladistically "true" dinosaurs, and if they are, what
were their earlier ancestors eating (or being eaten by).
I believe the oldest dinosaur is now the one in southern Brazil which
was something like 237 million years old, and it was over six feet long. I
would think its ancestors several million years earlier would have been
smaller (meter length or smaller), and I don't see why protofeathers on the
end of the tail couldn't have worked (maybe not at water ambushes, but at
least on dry land). As for intelligence, I still think Triassic predators
wouldn't have even come close to Cretaceous standards (which took 100
million years to achieve). If one doesn't like the word "progress", at
least "improvement" would apply.
I know that the Permian extinction was really, really bad, but is it
conceivable that dinosaurs actually arose in the late Permian, and at least
one species survived and began splitting into different clades very early in
the Triassic? Even if not, I think protofeathers could have easily arisen
in the Permian on dinosauromorphs.
From: "Rob Gay" <firstname.lastname@example.org>
Date: Thu, 21 Feb 2002 10:04:42 -0700
> I don't see why _Eoraptor_ or herrerasaurids couldn't have preyed upon
juveniles of other dinosaur species<
They very well may have. I think Ken's point here is that the vast majority
of Triassic predators were non-dinosaurian, so the highest predatory
pressure would also (probably) be from non dinosaurian predators.
>- or even their own. _Coelophysis_ apparently did - assuming the
specuimen enclosed by the rib cage of an adult represents cannibalism.<
For my comments on this, see the archives. But, its also important to point
out, I think, that even if we don't have evidence for cannibalism in
_Coelophysis_, it doesn't mean that it never happened...it just means we
don't have evidence for it, and cannot say for sure if it did or did not.
> And there were fairly large-sized (6m+) carnivorous dinosaurs in the
Triassic: _Gojirasaurus_, _Aliwalia_, and some undescribed critters (e.g.
from South America). They might have targeted small prosauropods and
Might have. But I think once again the fact that the large majority of
animals (in this case, herbivores) were non-dinosaurian would lead one to
the conclusion that therapsids, and non-dinosaurian archosaurs were the
main prey items of said dinosaurs.
When we're talking about predator/prey relationships in the Triassic, it is
very important to remember that with very few exceptions, were dinosaurs a
majority, or even a large minority, of the ecosystem.
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