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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.
-----Cheers, Ken
*****************************************
From: "Rob Gay" <rob@dinodomain.com>
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 juvenile
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 Late
Triassic: _Gojirasaurus_, _Aliwalia_, and some undescribed critters (e.g. from South America). They might have targeted small prosauropods and ornithischians.<
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.
Peace,
Rob




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