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RE: Deinonychus claw use and origin of flapping

> Date: Fri, 16 Dec 2011 14:12:29 +1100
> From: tijawi@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: Deinonychus claw use and origin of flapping
> Anthony Docimo <keenir@hotmail.com> 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?  
(besides ground-up
> > 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.
 ah, but 
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)