Re: "Dinosaurs Died Within Hours After Asteroid Hit Earth..."

[Mickey Mortimer <Mickey_Mortimer111@msn.com>]

David Marjanovic wrote-

> > > In that of purely morphological parsimony perhaps. If we only consider
> > > what the jaw looks like, it's a lori. If we consider how old it is,
this
> > > becomes a quite weird suggestion. And if we consider how difficult it
> would
> > > be to classify well-known Eocene and Paleocene birds from fragments
like
> that
> > > one, it becomes even more tenuous.
> >
> > That's too generalized to mean anything.  Are there any Paleogene taxa
> with
> > this loriine-like beak?
>
> No.
>
> > How about with a psittacid-like beak?
>
> No.

Well then, you can't use the argument "assignment of this specimen to this
clade is tenuous because although it resembles that clade this way, we know
of other specimens that resemble other clades in different ways".  It would
be like doubting a Chirostenotes dentary was related to oviraptorosaurs,
because although they share a lot of synapomorphies, we know it would be
difficult to classify other theropods (e.g. tyrannosaurids vs.
ornithomimids) from different fragments (e.g. caudal vertebrae, astragalus).

> > > Sure, a big gap in the fossil record is nothing new, ever longer live
> the
> > > champsosaurs. But this gap wouldn't span, say, the Middle Jurassic. It
> > > would span the fossil-rich Eocene and the comparably fossil-rich
> Paleocene.
> >
> > How many Paleocene and Eocene loons are known?
>
> Paleocene: none (I wrote "comparably" -- absence of sites of the quality
of
> Quercy, the London Clay, the Green River Fm, let alone Messel...). Eocene:
> one (*Colymboides anglicus*), according to Feduccia's book (1996).

So if loons can traverse the Paleocene and Eocene leaving a single known
specimen, why can't derived parrots (which live in more forested
environments, less amenable to preservation) traverse the epochs with no
known specimens?

> > > OK, more convincing, but scapulae and femora are unknown for lots of
> > > Mesozoic bird clades...
> >
> > Why do you insist on making that kind of argument?  It's like me saying
> "You
> > know, Tochisaurus' metatarsus shares a lot of synapomorphies with
> > troodontids, but with Bagaraatan, paronychodonts and Richardoestesia
> around
> > at the time with unknown metatarsi, I don't feel secure in referring it
to
> > the clade."
>
> We already have troodontids from this time and place, unlike the situation
> with cormorants. And I have some trouble imagining cormorants and flying
> hesperornithiforms coexisting... well... with anhingas and grebes and
> sungrebes coexisting with cormorants today, this doesn't sound so
convincing
> anymore.

Go back in history to 1922 and we wouldn't have.  I could just replace my
example with the Hell Creek mononykine.  No other verified alvarezsaurids
were known from North America before it was described, and the pubis of
Richardoestesia and Paronychodon is unknown.  Better doubt the pubis is
mononykine...  Distribution of taxa can easily be due to the vagaries of
history, preservation and exposure of sediments.  You're faced with a lack
of objectivity in deciding how far away is too far away, and how early/late
is too early/late.
And yes, there are a LOT of taxa with very similar niches living today.
That's definitely a flawed argument.

> > And procellariiformes are distinct ecologically, supporting the notion
> > neornithines/avians were diverse by the Mesozoic.
>
> Which tells us nothing either way about parrots.

But it does tell us Mesozoic neornithines were ecologically diverse, just as
Maastrichtian enantiornithines were.  So finding an ecological excuse for
why only neornithines survived seems futile.

Mickey Mortimer