Re: Cost in Aquatic Birds (the big one)

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

----- Original Message -----
From: "Jaime A. Headden" <qilongia@yahoo.com>
To: <dinosaur@usc.edu>
Cc: <david.marjanovic@gmx.at>
[no need to send me everything twice...]
Sent: Thursday, April 11, 2002 6:42 AM

Thanks to HP Tim Williams for anticipating some of my questions and thereby
shortening this post. :-)

>   You take a decidedly reductionist viewpoint here.

Well, the whole is certainly more than the sum of its parts, but it is
certainly not more than the sum of its parts + their interactions + the
interactions of the interactions. :-)

>   Positive data exists for several theories, including the Hopp and Orsen
> brooding hypothesis [HOBHY, or "hobby"] which posits the wingfolding and
> feather assymetry are effective by arm position over nests and broods.
> This is very friendly to the display theory, possible as comparative
> adaptational responses in a single ecosystem;

HOBHY is very friendly to pretty much everything. It provides the ground-up
and the vertical running hypotheses with an explanation of how wings
evolved; it provides the BCF hypothesis with one for why wing feathers and
not a patagium evolved; it provides the display hypothesis with one for why
the arms and not the tail or something else was used for display; and it
provides the FUCHSIA hypothesis with one for why neither *Compsognathus
"corallestris"*- like paddles nor penguin-like ones evolved. It's
_wonderful_, I tell you. :-)
(According to http://www.dinosauria.com/jdp/evol/evolfact.htm some or all of
these "hypotheses" might better be called speculations. I certainly never
wrote FUCHSIA were a theory.)

> there is the BCF theory, in
> which wing and arm structure are descendant features as a result of a
> primitive arboreal nature of theropods (this is possible given some
> features of *Eoraptor*).

Of *Eoraptor*? That's interesting. Please explain.

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

Sorry, not in principle, in this special case. I should have been more
explicit.

> <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.>
>
>   No one tries to put them together.

That's new :-)

> Flapping (or the ascent-descent
> humeral stroke), the power stroke, aerialism are all separate qualities
> that have been demonstrated in other theories. One such is the predatory
> strike in the ground up hypothesis; which has been adapted in Chatterjee's
> trunk-climbing.

I haven't been explicit enough... I also separate the ability to do the
famous predatory stroke and using it for locomotion. To explain the
evolution of the latter is what I use FUCHSIA for.

> <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.)>
>
>   How, o how can it be supported without any positive data?

By theoretical considerations (biomechanics and stuff), and by phylogenetic
bracketing -- all well-enough known primarily flightless insects are
strictly terrestrial incl. fossorial, all living basal Pterygota have
aquatic larvae, and many or all of them stay closely associated to water as
adults. Not to mention the behavior of adult stone"flies" (which are basal
Pterygota). This can probably be called a hypothesis already.

>   [on my use of "near-shore paravians" as antecedent to the avian
> condition]

erm, no, on arboreal features in bird relatives

> <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).>
>
>   I mean the general nature of elongate arms,

I'd expect _mobile_ elongate arms, something like my own. Arms that are just
elongate, but have amazingly stiff forearms and wrists and a reduced number
of fingers, should have evolved for something else.

> large man[u]al claws,

Plesiomorphy. IMHO an adaptation to grasping prey, just like elongate arms
(for grasping prey as fast, not as strongly, as possible -- *Tyrannosaurus*
is better suited for the latter) (elongate arms are co-produced by HOBHY).

> galago-like brachial structures from the
> integument (feathers and the like are not integument [...]),

Do you think so? What would that be?

> balancing structures

Such as? The stiff tail? That's good for running, and (if feathered as in
Archie) for steering in air and/or water; in a climber I'd expect either no
tail at all (as in anthropoids, *Indri indri*, *Arctocebus calabarensis* and
others), or a long, prehensile one, or a long, mobile one in the first place
(*Lemur*, *Propithecus*), but not one that's as short and stiff as that of
*Microraptor*.

> and typical arboreal features.

Such as?

> I posit *Microraptor* as a possible twig-hugger,

Well, it was certainly better at twig-hugging than I, if only because of its
size, but maybe not at getting at a twig.

> but my concept did not include this animal specifically.

But like I use Archie for FUCHSIA, you use it as a descendant of an ancestor
of birds, that has retained a crucial part of the ancestor's lifestyle and
adaptations, don't you? :-)

> <<were predicatory to the flight-stroke.>>
>
> [...]
>
>   Of or involving prediction, or indicating things that come before
> [others]; precedent.

Thanks.

> <There's one big argument against ground-up... ground-living birds fly
> rarely if they still can. Roadrunners almost never fly,>
>
>   I would disagree. They [roadrunners] are very flight-capable, and have
> seen them occasionally take to flight while taking on or pursuing prey --
> in this they are very similar to crows and other corvids -- they just
> spend much of their time on the ground. Same for tinamous. Some birds
> despite their terrestriality can still be operative fliers and are not
> untile in these scenarios.

But is there a case that a species that flies very much has evolved in such
a terrestrial group?

> <Information includes as a character, is whether it has an extra exit for
> V1. Currently having one unites Tyrannoraptora without dromaeosaurs +
> Archie.>
>
>   My look at the material (photo and drawing) appears to suggest not. An
> expanded opening for the trigeminal so that the first branch of the nerve
> split within the bone or at the apse, or the lack of this condition to
> begin with, is not something we can tell for now.

Mhm... so I can wait for another paper. :-| Thanks, anyway, of course.

> <Is there a paper to wait for? :-)>
>
>   At some point in time, hopefuly so.

:-)

>   Now, for the big part:
>
>   Absence of testability is the flaw here. FUSCHIA [sic]
> cannot be tested, only conjectured.

I disagree. There are several ways to falsify at least part of it. We just
got one such suggestion about biomechanics. -- The wildest hypotheses can be
testable. Remember the idea that in every black hole a new universe is born,
with natural laws slightly different from those of its ancestor, allowing
evolution? (Would explain why we can exist in this universe -- the
conditions for producing a maximum number of black holes are also those that
allow most life; those universes that produce most black holes, and
therefore most offspring, also produce most life; so we are most likely to
find ourselves in a universe that produces many black holes.) There is no
known way to find out if there's more than one universe. Nevertheless the
whole thing is falsifiable: Find one neutron star that's twice as heavy as
our sun, and the whole affair is wrong (because then the conditions for most
life and most black holes differ) and ready for the trash can.

> It is not even a theory, but an hypothesis.

Of course it's not a theory. See above.
(Now that I think of it... "an hypothesis"? I've read that often. Is the h
not pronounced?)

> Particulate to
> the theory of the origin of flight is the application of the concept to
> the fossil record,

which is, in the relevant time (end-Tr -- end-J), damn badly known,

> and in this, some other theories provide _some_
> solutions:
>
>   BCF -- small theropods lived in trees, produce limbs and grasping
> structures

which they don't have... why is there no non-pygostylian, except the aye-aye
dino, with a decent grasping foot like even that of a chicken or
*Confuciusornis sanctus*, and why does the hallux of chickens start high up
on the metatarsus and grows and shifts into a more distal position later in
ontogeny?

> and "typical" theropod qualities as a result of their
> arboreality, leading to thye preclusion of Aves to develop flight-worthy
> limbs.

Requires an explanation for how arboreality can lead to powered flight...

> Birds have such structures only as a result of their ancestry, and
> thus, birds came first;

I can agree with that... :-)

>   Evidence: small basal theropods have semi-stiff tails, [...] long arms,

See above.

> large toes,

Plesiomorphy; good for hopping, walking (for small animals), running...

> > and triangular skulls, adaptational in some ways to arboreal life.

Aren't triangular skulls the plesiomorphy for (*Solenodonsaurus* + Amniota)?

> Grasping manus may have led to the power stroke in other theropods. E.G.,
> *Eoraptor* and *Herrerasaurus*.

To the ability to flap, I agree. See above.

>   BAMM -- two competing qualities: AFIT [arboreal flying in theropods],
> and THATF [theropods are terrestrial _first_]. The first has theropods
> clamboring in the trees and begin to leap from one branch to the other,
> developing primate-like crania

Primates have quite some diversity in skull shapes. What do you mean?

> and arms

Theropod arms are primate-like? You're kidding. ~:-|

> to better live in a
> fully-three-dimensional world;

which also arises when one is e. g. pursuing prey through a dense forest, or
attacks prey that is much smaller than oneself, or jumps at prey, right?

> then start gliding, and in the effort of controlling the flight, develop
the
> flapping capability, and refinement produces the power stroke.

I still can't see how the control of gliding can lead to flapping.

>   Evidence: fossils indicate arboreal maniraptorans

Fossils indicate that some maniraptorans might possibly have been able to
climb trees, or maybe not. Waiting for more papers & fossils.

> [...] but had many features that equate to the
> development of incipient gliding;

Such as?

> basal birds could not use a power stroke.

(I'm waiting for how the discussion develops.)

> *Sinornithosaurus* looks fairly galago-like

Hm. I have paintings of *Galago crassicaudata* (aka *Otolemur
crassicaudatus*) and *Galago senegalensis* in front of me. Both are smaller
than *Sinornithosaurus* (but not *Microraptor*, so that may not say much).
Both have relatively longer tails, especially *G. senegalensis*. Both have
considerably shorter arms than *Sinornithosaurus* (in relation to hindlimb
length). At least *G. crassicaudata* has fully opposable halluces and
pollices, unlike *Sinornithosaurus*. Both have much more mobile arms and
hands than any dinosaur. Both have directly forward-facing eyes, unlike
*Sinornithosaurus* (and AFAIK still much more so than *Tyrannosaurus*).

> Hair-like rachis and barbs
> develope as an effect of primitive structures being influenced by drag.

This should be testable experimentally :-)

> Fossil succession is indicative of an increasingly complex arboreal and
> leaping complex. The glider is not in evidence as of yet.

Fossil succession? Through what time or phylogenetic hypothesis?

>   The second theory holds that the long arms are prey-capture tools and
> that development of the prey-capture strategy produced the predatory
> strike. Display or brooding may have produced the feathers that were used
> for wings.
>   Evidence: *Caudipteryx* is clearly terrestrial, and the development of
> structures in maniraptoriforms indicate that the arm was modified without
> special "hair" or "protofeathers" from compsognathid to bird. Thus, flight
> and the development of the feathers were not neccessarily related.
> Brooding and display hypothesis are also compatible with this concept.

Well, I agree with all that. It just doesn't explain flight itself.

>   BAND -- small arboreal reptiles ... nuff' said.
>   Evidence: [...]
>
>   There is clear evidence for each theory, despite claims to the contrary.

You won't call the evidence for BAND you listed "clear evidence", will you?
:-)

>   FUSCHIA [sic] adds no data

What happens if I write "only fossils can add _data_"?

> that can be seen that actually allows it to be
> tested in light of the competition.

I've offered and been offered some onlist.

> Modern birds, though admittedly derived, compare well with other
> aquatic forms that indicate developing propulsive mechanics leads to a
> nearly permanent aquatic life, and that use of adaptations to swimming do
> not tend to develop in non-aquatic animals.

Dippers...

> Few animals learn to swim from
> a non-aquatic form, then become terrestrial or aerial again.

You know, I happen to agree. We just have slightly different opinions on
what "few" exactly is. :-)

> Thus, there
> is sufficient data to contend that FUSCHIA adds no useful data to the
> discussion, as I see the situation.

I use FUCHSIA as a scenario (aka just-so story :-> ) for why birds not just
can do the "predatory stroke" but also use it for moving. That's all. :-)