Re: Cost in Aquatic Birds (long)

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Jaime A. Headden" <qilongia@yahoo.com>
Sent: Sunday, April 07, 2002 6:26 AM


> David Marjanovic (david.marjanovic@gmx.at) wrote:
>
> [on dippers being conditional to many of the previous points I made about
> the nature of the mechanics and anatomy that I use to preclude
> *Archaeopteryx* as being aquatic]

See below for "aquatic".

>   The use of dippers (*Cinclus cinclus*,

(and 4 other species)

> Cinclidae,

(monotypic)

> an ally of the wren and closely allied to the Troglodytidae
> [of which wrens proper are a member])

ah, thanks for that info (and for confirming what a wren is in English :-) )

> is flawed [again] by the very nature of it's lack of aquatic
> features. Applying the lack fo these features then to a fossil makes this
> even so more problematic to derived any positive evidence to support the
> theory. There is no other means by which we can know *Archaeopteryx* may
> have had any aquatic behavior, as all this data on dippers is just that,
> behavioral. It does not fossilize. To apply behavior to a fossil is a
> long-frowed upon practice as it in no way imparts positive, testable data
> and thus is no evidence of anything.

Almost. The only positive evidence I can hope for are fossilized skin flaps
on the nostrils... bit improbable :-]
Well, so far I think all other explanations for the wingstroke are even more
improbable than FUCHSIA, and just as behavioral and testable respectively
not, and assumed to have taken place at the same time where the fossil
record is meagre in general. :-)

> <This is the _strength_ of the hypothesis. I can _decouple_ the evolution
> of _wings_ and the evolution of _the wing stroke_. Why have wings? For
> brooding sensu lato. And whatever sorts of display.>
>
>   There are easily hypotheses that more easily explain the wing stroke of
> archie without having to plop it in the water.

Such as?
I can think of
- a glider suddenly starting to flap out of nowhere. Improbable and
untestable.
- a terrestrial winged theropod jumping and flapping around for display. It
may be a bit hard to explain the evolution and then retention of the ability
to fly in a cursorial animal... and it's just as behavioral and untestable,
if not slightly more so.
- Vertical running. Sounds interesting to say the least, but I haven't seen
the SVP talk, or any video of a bird doing that, and am waiting for the
paper. =8-]
- I'm pretty certain I've missed some... I appreciate suggestions. Really,
if they are more testable than FUCHSIA :-)

> In fact, the form of the
> scapulocoracoid, humerus, and forearm all suggest that modified arm
> anatomy has occured. It's up to the nature of the muscles on these bones
> that can assist in knowing wether the animal could use a flight stroke, as
> well as the shape of the humeral glenoid. Archie has these features, for
> the most part, though relatively reduced compared to later birds.

Can "reduced" and "incipient" be told apart?

> Therefore it seems that there is no logical reason why this animal would
> need to persist in a maladaptive environment to explain the flight stroke.

Hm. Dippers also persist in what is just as maladaptive for them -- survival
of all those that are fit enough :-)

>   There are countless reasosn why Archie is best conceived as terrestrial
> or semi-arboreal in nature,

Dippers are terrestrial, apart from behavioral mood swings :-> , and
probably don't refuse to perch on a bush :-)
(Archie, in contrast, must have been very bad at perching, judging from its
feet. And if all specimens were not windblown for 200 km, then there may not
have been enough high trees to make the term "arboreal" useful.)

> and it is up to Ebel or Marjanovic to explain
> how the aquaeous environment may have been better suited to explain the
> anatomy of Archie (not just the wingstroke) when physics appear to tend to
> make water a bad place to be for this animal.

See below...

> <I don't think so.>
>
>   To jump from island to island would suggest that the animal would need
> to be terrestrial in nature. Otherwise, why not stay in the sea?

Because swimming so far over a sea chock-full of plesiosaurs, ichthyosaurs
and sea crocs, is far too exhaustive and dangerous for such a little
maladapted animal. See below.

> <Just as dippers ignore it? :^)>
>
>   Dippers are in, then out. They thrust strongly, and get out in a hurry.

And _THIS_ <trumpets> is what I imagine basal Eumaniraptora
(Maniraptoriformes of most others by content) did for a living. For maybe
the tenth time, I don't think Archie or any other known non-ornithuran
dinosaur was aquatic in the full sense of the word

> <Unlike Ebel, I don't think the arms elongated _after_ diving behavior
> evolved, but before... for... brooding. :-)>
>
>   A condition that would have provided the flight-stroke as a side-effect
> to the folding mechanism, rendering the water unneccesary.

And once such an animal got crazy, folded and unfolded its wings again and
again, faster and faster, and suddenly found it had lifted off? :-/ -- In
water such a behavior might even be adaptive :-)
        My incitation for using FUCHSIA at all is that there is a difference
between having the ability to flap and using it for flight; these need to be
explained separately.

> <I know they are the exception. That's what makes them fascinating. :-)>
>
>   Because the only thing that puts them in the water is their behavior,
> not anatomy.

Dippers need not modify their anatomy for underwater flight because they
_can already_ fly in air. Someone who starts to fly underwater, without
being able to fly in air, should profit of evolving just those modifications
that can be used for flight in air.

> <No shorter than Archie's AFAIK.>
>
>   Dipper wings are longer and tapered.

Tapered? That might be a real piece of evidence, as Archie's wings are not
tapered at all (and Archie is, alas, the only fossil of a basal
eumaniraptoran that may possibly have led such a lifestyle).

> [on thunniform bodyshape:]
>
> <Do dippers?>
>
>   Looking at pictures and footage of dippers diving and not, no. And
> certainly not *Archaeopteryx*.

Fine :-)

> <Looks like insects have done it: evolved tracheal gills, later flapped
> them for swimming, later flapped them for skimming around while standing
> on the water, as stoneflies still do, then flapped them for flying.>
>
>   Insects *started* in the water,

To assume that Pterygota started in the water is unparsimonious, as all
known sister groups (successively: Zygentoma, Archaeognatha, and all
Entognatha) are strictly terrestrial (incl. fossorial).

> and stonefly _larvae_ stay in the water,

Adult stoneflies often stay _on_ the water, standing on top of it and
flapping vigorously, which drives them forwards but not upwards.

> Besides, the sequence above is conjectural, and fossil data is so far
> lacking on this conclusion.

Yep. But it is the best-supported scenario so far. (I only know 2 others:
one is the classical arboreal theory that starts with gliders, the other
explains the evolution of wings [as solar panels] but not that of flight.)

> <"Became so highly derived" is not what I think happened to the
> [hypothetical] diving ancestors of birds; when you already have wings and
> laterally-facing glenoids, it may largely be behavior, just as you wrote
> diving in dippers is just behavior.]>
>
>   The data suggest that many of the features found in Archie are
> scansorial or arborial (or cliff-clinging)

(in the absence of cliffs)

> in nature, including claw geometry (Yalden, 1985, 1997),

Other studies come to different results. And many of those that advocate
arboreality use the finger claws for their argument -- these are just
primitively raptorial IMNSHO.

> and the fossil data from animals from
> northeast China suggest that the arboreal features of near-shore paravians

You mean the pretty long hallux of *Microraptor*? Hm. It's still shorter
than in perching birds (and most ground-living ones, for that matter) and is
apparently attached rather high on the metatarsus (as Archie's). We need
better articulated fossils to get more clarity here, and less crushed ones
to tell how reverted that toe was (same for Archie).

> were predicatory to the flight-stroke.

I don't understand what you mean by predicatory. My (not very big)
dictionary only connects it with preaching.

> The grounds-up and trees-down and
> even George's BCF all indicate this,

There's one big argument against ground-up... ground-living birds fly rarely
if they still can. Roadrunners almost never fly, and wild chickens in the
jungle of SE Asia apparently don't do it much more often. I think I've said
often enough what I think of trees-down. Well, I need the not yet existing
paper on vertical running.

> You take behavior as a quality that cannot be substantiated,
> and thus should render the point moot.

Just as moot as any other scenario that seeks to explain how flight evolved.
:-)

> <Then dippers are not adapted to swimming. Then maybe Archie was just as
> > little adapted to swimming. :-)>
>
>   Take that a little further, and instead of trying to put Archie in the
> water, you think "Archaeopteryx doesn't have any features that could
> actually indicate to me that it was able to swim or would have provided
> the later birds (Pygostylia) with the flight stroke -- in fact, evidence
> suggests that Archaeopteryx may have already have had something similar to
> the flight stroke ..."

I've confused you by taking Archie, as Ebel does, as the prime example.
Unlike Ebel, I don't think Archie was an ancestor or even a particularly
close relative to Pygostylia. But it is the only known animal anywhere near
this position that may possibly have made up this ecological niche. I do
agree the evidence that Archie actually did that is pretty circumstantial
(while there is no evidence it could not have done that).
        Of course if Archie had nothing similar to the flight stroke I
couldn't possibly claim it was an underwater _flier_.

>   The note that even Confuciusornithidae lack the Ornithurinae triosseal
> canal and any form of humeral rotation at the glenoid, thus even a more
> advanced bird _still_ doesn't have this quality. Archaeopteryx was
> apparently unsuccessful if it _did_ do this.

If it did do what exactly? Apparently the sort of underwater flight dippers
practice doesn't require a more sophisticated flight apparatus than Archie
has (hey, that's pretty testable!).

> <Why maneuvering?>
>
> [...]

Thanks for the info.

> < [...] Anyway, only a well-resolved phylogeny will be able to
> tell whether they (and those of *Protarchaeopteryx* and dromaeosaurs)
> are a reversal.>
>
>   So I guess the well-resolved enough? 6 max trees produced by the
> Sinovenator analysis is not pleasing.

Subjectively at least, it isn't. Even if only because it doesn't include
*Microraptor* that appears to have introduced impressive polytomies when
*Sinovenator* was presented at SVP, unpublished fossils like the aye-aye
dino that might, who knows, screw it all up even more (and we've been
promised fossils that "will blow" us "all AWAY!!!"), and heaps of unknown
Jurassic skeletons of troodontids, dromaeosaurs and so on! :-) -- Anyway, no
problem if unserrated teeth did evolve 5 or 10 times in that part of the
tree. I just thought it might be suspicious that animals with unserrated
teeth cluster there.

> Very good stats regarding homoplasy
> and consistency, and it is becoming evident that this relationship is
> closest to the "true" tree than any other published analysis.

I agree *Sinovenator* has destroyed Arctometatarsalia and Bullatosauria as
originally perceived. What I am interested in, and what neither the paper
states nor the Suppl. Information includes as a character, is whether it has
an extra exit for V1. Currently having one unites Tyrannoraptora without
dromaeosaurs + Archie.

> The absence of serrations, as I hope to show soon, [...]

Is there a paper to wait for? :-)