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Re: Protungulatum index; pterosaur finger.



> Bois asked David M. about the spontaneous generation of Paleocene mammals:
>
> > > Did it ride in on
> > > the bolide?  Did it fly in from the coast?  It was right there at the
> > > very earliest Puercan 1...
> >
> > When? 1 Ma after the K-T? 5 Ma?
>
> No, right at the very start--time zero!  Pu2 starts at about 400,000 years
> after the K/T; but Protungulatum is there--I believe it's the idex
> fossil!--right at the beginning of Pu1.

Now that's more interesting. Maybe evolution went REALLY fast after the
K-T... or we "just" have to wait for loads more fossils. After all, there's
no good morphological phylogeny of Placentalia so far, and the molecular
ones won't tell us where e. g. Cimolesta and Leptictida sit in the tree.
        Alternative: Immigration from an unknown place right after the K-T.
:-)

> > > > Then please suggest some structural constraints.
>
> Quoting Romer: [...]

My God, quoting Romer. Ignoring the last _fourty_ years of pterosaur
research. :-o I'm genuinely surprised.

> OK.  He was writing before the bolide was discovered.

That almost doesn't matter, compared to how pterosaurs are understood now
vs. 40 years ago.

> But his hypothesis
> must still be taken seriously.

Assuming what you snipped weren't lots of good arguments, it wasn't even a
hypothesis but a speculation.

> If he is right about birds' abilities
> relative to pterosaurs',

He isn't. :-) Read something newer, such as Wellnhofer's 1991 encyclopedia
(but don't trust it on taxonomy, that's outdated).

> the following behaviors should be considered:
> - mobbing of larger falconiforms

Speculative larger falconiforms.

> by smaller pterosaurs

Actually... I thought we were talking of how the very last pterosaurs, all
of which were, as far as known to date, gigantic azhdarchids, died out. --
Few really small adult pterosaurs are known. Adult *Rhamphorhynchus* and
*Pterodactylus* reached over 2 m wingspan.

> would be unlikely
> because feathers confer greater manueverability to creatures of equal size
> (therefore, larger birds could be just as--or more--manueverable as
smaller
> pterosaurs)

Wrong. According to DA the cambered wings of bats give them the great
maneuverability necessary for hunting insects on the wing.

> -large flying pterosaurs would be sitting ducks.  Falconiforms drop on
them
> from on high, etc., etc.

This requires 2 improbable assumptions --
1. _Big_ falconiforms, eagle-size upwards. Where are they in the
_Paleogene_?
2. Pterosaurs were somehow unable to use their enormous, pointed beaks and
their finger claws.

> - just as bats are banished (largely) from the day niche by birds, the
even
> less effective pterosaur fliers would be prey to Cretaceous equivalents
(if
> any existed!)--predation is the key, here

Just as passerines keep albatrosses from flying during the day -- oops...

> -baby pterosaurs must be nurtured for longer than baby birds because they
> are heavier and develop less thrust than baby pterosaurs (going out on a
> speculative limb here).

So speculative that I needn't even answer IMHO. Why "less thrust"?
Azhdarchids had powerful flapping abilities.

> This additional PI costs

What's that? I don't understand it even if I fill in "*Protungulatum*
index".

> -birds like caracara hawk perch near nests of larger rhea...rhea can
attack
> and kill the hawk except that it just flies away...waiting for the rifght
> moment it snatches the less agile parent's chick and flies off with
> impunity.

You're forgetting that
1. rheas still aren't extinct. Even though for most of the Cenozoic there
were predators that were able to run after them -- phorusracoids.
2. Why kill? Just keep away.
3. Waiting for the right moment... but not until it starves.

> Hoplelessly clumsy pterosaur walkers--

Wrong. There was a beautiful paper on the tracks called *Pteraichnus* --
pterosaurs were pretty fast and elegant walkers. -- You're assuming that
azhdarchids nested on the ground. Is any evidence for or against known?

> --must watch their babies more carefully.

Maybe they did :-)

One more question: Why didn't *Boluochia*, a real fossil falconiform-mimic
bird, take over the world in the mid-EK?