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Good point, the elbow is twisting into the curve as well. Kind of goes against your general argument .

QUOTE (Jarlaxle @ Jan 30 2023, 08:21 PM)

Good point, the elbow is twisting into the curve as well. Kind of goes against your general argument .

NO IT ISN'T?????????????????????????????????????

Do you think feathers are rigidly attached and never move?????

Do you think birds can't twist their shoulders????????

What kind of utterly insane misconception is making you think the elbow is bending in any way but its intended direction???????????????????????????

That's a lot of question marks.


As far as I can tell the way that the elbow twists in the wing of a bird is within a 2D plane between the two segments that make up the limb prior to the wrist. Any movement of that elbow in a twisting manner is performed at the shoulder joint, which as far as I can interpret is essentially what is being said about the sauce back except we're dealing with three segments prior to a wrist rather than two.

There was previous argument that the wrist is unable to twist due to their only being a single bone in the segment prior to that joint, which I personally don't think is a very good argument but seems to be what is established, while (later established) all the twisting that would occur in the limb beyond the shoulder occurring at the base of the digits.

In the wing this would essentially allow the same degree of motion as would be found in a bird wing, assuming that the base of the wing toe is allowed to have the same degree of motion as a standard wrist.

I don't really see too much issue in any of this, if one were to simply take the whole situation and assume what has previously been attempted to be applied to the wrist to simply be transferred to the joint at the base of the wing toe instead, since that is now what should be considered the wing wrist of a flying sauce back.

It does make me wonder if we ought to differentiate between the bases of the two toes, with The walking toe base joint being called an ankle and the adjacent joint which is what attaches the wing toe to the single "foot" bone being called a wrist simply due to analogies to what you would find in a bird.

This post has been edited by colddigger: Jan 30 2023, 06:31 PM

You know what, Jarlaxle, if you have access to a place that sells bone-in chicken wings, please go buy and examine one. It'll save us a lot of ridiculous arguing.

I do actually have a whole rooster that I killed in my freezer that I could rip a wing off of and pull the bones out of and we can look at it, I actually looked at one of those and it was part of why I was confused about the discussion of twisting motion in bird wings prior when it seemed to have been claimed that they cannot move outside of a 2d plane beyond the shoulder.

If you guys want to actually look at a crappy photograph of bird bones, not particularly cleaned.

QUOTE (colddigger @ Jan 30 2023, 10:34 PM)

I do actually have a whole rooster that I killed in my freezer that I could rip a wing off of and pull the bones out of and we can look at it, I actually looked at one of those and it was part of why I was confused about the discussion of twisting motion in bird wings prior when it seemed to have been claimed that they cannot move outside of a 2d plane beyond the shoulder. If you guys want to actually look at a crappy photograph of bird bones, not particularly cleaned.

Wait what, you killed a rooster?

But yeah, i do think getting pictures would be helpful. maybe first take pictures of its range of motion with the meat on.

Again you are doubling down on bad arguments: Not only does the flexibility of the wing joint in a carcass not indicative of the flexibility when it was alive, if we were to assume it does it would support a more flexible joint not less.

I've ignored it for the health of the conversation, but given the condensing name calling that's out of the window, and I should probably tackle at least one of the previously doubled down bad argument anyway:





False comparison, basically a strawman, but still wrong: man powered ornithopters were able to produce enough lift to push themselves, while people flapping wing extensions on their arms, often while jumping from high buildings, were... well, sacrifices for science. Given your Mark Sargent type influence here I'm going to just ask that anyone reading the convo to not try to do this.

Can you at least trace the "curve" you're talking about? Because the only curves I see are a patagium (or stretchy skin membrane) between the shoulder and the wrist, and feathers being pulled to a different angle by the hand.

QUOTE (colddigger @ Jan 31 2023, 02:34 AM)

I do actually have a whole rooster that I killed in my freezer that I could rip a wing off of and pull the bones out of and we can look at it, I actually looked at one of those and it was part of why I was confused about the discussion of twisting motion in bird wings prior when it seemed to have been claimed that they cannot move outside of a 2d plane beyond the shoulder..

As far as I can tell that is still the claim and the basis of the argument against the visorbill's ankle motion

QUOTE (Jarlaxle @ Jan 30 2023, 08:51 PM)

QUOTE (colddigger @ Jan 31 2023, 02:34 AM) I do actually have a whole rooster that I killed in my freezer that I could rip a wing off of and pull the bones out of and we can look at it, I actually looked at one of those and it was part of why I was confused about the discussion of twisting motion in bird wings prior when it seemed to have been claimed that they cannot move outside of a 2d plane beyond the shoulder.. As far as I can tell that is still the claim and the basis of the argument against the visorbill's ankle motion

The ankle, which might more accurately be called the second knee, is fulfilling the same role as the elbow in a bird's wing, which indeed is restricted to a plane. There is non-planar movement in the wing toe. But not in the elbow.

However, a bird gets what has the same ultimate effect as non-planar movement from the twisting of the shoulder. A sauceback can get the same exact degree of effect from twisting the hip, but the knee and heel remain on the same plane.

The problem is that instead of showing that, you show the heel bending perpendicular to the plane of rotation clearly visible in the knee joint. That can't happen.

That could be solved by shrinking the foot bone to the point of being visibly negligible once meat is on top, and actually I hold curiosity and whether that is able to be shifted around in that part of the wing once it's small enough and become a different form of joint.

But I could also be wrong about that too.

QUOTE (Jarlaxle @ Jan 30 2023, 10:48 PM)

Again you are doubling down on bad arguments: Not only does the flexibility of the wing joint in a carcass not indicative of the flexibility when it was alive, if we were to assume it does it would support a more flexible joint not less. I've ignored it for the health of the conversation, but given the condensing name calling that's out of the window, and I should probably tackle at least one of the previously doubled down bad argument anyway: False comparison, basically a strawman, but still wrong: man powered ornithopters were able to produce enough lift to push themselves, while people flapping wing extensions on their arms, often while jumping from high buildings, were... well, sacrifices for science. Given your Mark Sargent type influence here I'm going to just ask that anyone reading the convo to not try to do this.

Its worth noting that all of these are machines, not living things...

QUOTE (colddigger @ Jan 31 2023, 03:15 AM)

That could be solved by shrinking the foot bone to the point of being visibly negligible once meat is on top, and actually I hold curiosity and whether that is able to be shifted around in that part of the wing once it's small enough and become a different form of joint. But I could also be wrong about that too.

That could work, but why is that needed?

Another alternative is that the vertical range of motion can be provided entirely be the turning of the knee while the knee covers the the horizontal motion achieving the same results, but both of those options seem less realistic then just simply gaining flexibiliy around the ankle (or "second knee", or "wrist", or... Albert, might as well just call it an Albert). Why is that even needed? What prevents the ankle from doing that across two generations? Why can so many species IRL and in Sagan do that all the time, for everything from arboreal life to swimming to digging, but somehow this one joint can't?

Usually, organisms don't change joint directions when they change their locomotion, and instead work within their limits.

Well, I'm just considering that it may be easier to transition to a more mobile joint from the apparent saddle shaped joint of the toes rather than the hinge-shaped joint that all the higher parts of the leg seem to use.

It also would mean that you would have more muscles pulling in more directions available to work with and mess with in order to achieve new movements.

Although the musculature diagram of the sauce back doesn't seem to fully elaborate on this, the muscles attached to the toes must be rather complex with many different "lobes" to them which would allow for more adjustments in how things are attached and how things are pulled. Which would translate into more mobility in the outer sections of the wing.

This, as well as turning that saddle joint of the wing toe into a ball joint which can wiggle waggle as the rest of the limb is rapidly agitated by muscles, I think plays very well with the fluttering way of flying.

I imagine that if the single football is shrunk then that movement from the rest of the limb outward can be pretty comfortably transferred rather than relying on the Albert joint directly.


I also wonder if this would results in the walking toes to dangle underneath like a bee when flying. Which is really hilarious sounding to me, but also easily sidestepped by just tucking them away.


I guess, where I'm coming from with my preference for the tow base as opposed to the Albert joint is just that it's more conservative once elaborations were applied.

This post has been edited by colddigger: Jan 30 2023, 08:24 PM