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RE: Deinonychus claw use and origin of flapping
> Date: Fri, 16 Dec 2011 14:12:29 +1100
> From: firstname.lastname@example.org
> To: email@example.com
> Subject: Re: Deinonychus claw use and origin of flapping
> Anthony Docimo <firstname.lastname@example.org> wrote:
> > which dodges the question of what they did before their family could fly.
> No, it doesn't dodge the question at all. We can't assume that the
> ancestors of birds were arboreal *before* they could fly.
so you don't think dinosaurs could handle slopes, and you don't think
dinosaurs could handle trees. short of leaping off sauropods, what's left?
> > it's one of the earliest origin-of-dinosaur theories I ever heard of (in
> > both senses of "early")
> > basically, dinosaurs evolved from something semi-aquatic like a croc, which
> > grew longer and longer hind limbs (for swimming? i
> > don't recall), until it was bipedal.
> I haven't read this paper. I'm betting _Lagosuchus_ hasn't read it either.
i think it was before I read about Lagosuchus. I think it may have been before
I even read "Predatory Dinosaurs of the World" or Harrison's Eden books.
> > you don't have to be specialized for something in order to deal with it.
> Negotiating steep, unstable terrain such as steep cliff where one slip
> means plunging to your death... nah, I think you *do* have to be
> specialized for this.
see bottom of the post. I never said unscalable terrain - I said uneven
terrain. you know...hills. mountains both high and low.
> > elephants can swim - that isn't because they're specialized for life in the
> > water.
> Elephants probably aren't the best example of your analogy; the
> earliest members of the Proboscidea were probably aquatic.
amphibious, maybe...but not specialized for an aquatic life (like manatees are)
so yeah, still a good analogy.
> > dinosaurs dominated terrestrial niches throughout the Jurassic and
> > Cretaceous and at least part of the Triassic. just as
> > pterosaurs ruled the Mesozoic skies (later time-sharing with birds), and
> > just as marine reptiles ruled the seas, dinosaurs ruled the
> > land.
> It think your editorial isn't giving sufficient credit to
> non-dinosaurian diapsids, or to synapsids such as mammals. There is a
> difference between "dominate" and "monopolize". If we are careful
> about definitions, it could be said that dinosaurs "dominated"
> terrestrial niches through most of the Mesozoic.
> But I'm sure there
> were plenty of terrestrial niches that remained devoid of dinosaurs.
sure. but *hills*?
> If we are going by numbers of species, and limiting ourselves to
> metazoans, then arthropods ruled the land during the Mesozoic. They
> still do.
not arguing either of those points.
> > and given that the ground is almost never smooth and uniformly even*,
> > animals have developed the ability to handle
> > themselves on uneven terrain.
> Two things:
> (1) Goats are specialized for this lifestyle, because those goats that
> live in steep, scree-ridden terrains have to contend with a *very*
> challenging environment.
1a) Goats are not the only mammals on Earth larger than a big Norway Rat or
1b) We have intermediate and passable analogues showing stages between "goat"
and "primitive monothere mammal". so goats are more plausible than a
non-dinosaurian creature specialized to live on hills and slopes who left no
fossils of itself or any relatives.
> (2) I've no doubt that dinosaurs (the non-avian kind) could handle
> themselves on uneven terrain. But the terrain that many goats have to
> contend with represents a whole new level of "uneven". No good can
> come from comparing dinosaurs to goats.
I'm not comparing dinosaurs to goats - I'm not even talking about the vertical
tepui that you seem to visualize every time someone says "uneven ground". (its
understandable - Sir A.C.Doyle wrote "The Lost World" after hearing about the
lost worlds of tepui)