Oldest Known Arm Bone - Land/Sea Link

Hey everybody,
This is my first post, and I don't really know how things work yet, so if I do anything stupid or annoying, I'll be happy if you slap me upside the head about it (just not too hard )Anyway, back on subject, how do lungfish benefit from their fins being like they are? Do they use them as limbs, like for digging and stuff, or do they use them exclusively as fins?

The structure of the foot of a primitive tetrapod is vastly different than the structure of a lungfish fin.First, the fin. The tip of a lungfish fin has 8 bones laid out in a simple geometrical pattern. There are no more than 5 joints, and the joints cannot be individually controlled. The rest of the fin is made up of a backbone-like segmented chain of about 12-14 bones. This backbone allows the fin to be flexible, which is useful for swimming. Two long, narrow bones come off of each bone segment to give the fin shape. The spine of the fin is flexible, and can bend along its entire length. The small bones coming off the fin do not have flexible joints, though. The fin is minimally controllable, only the main set of joints can be moved, and they are moved as a group. These fins are not connected to the skeletal structure, only to soft tissue. This prevents the fish from using the fins to support itself on land; at most the fish could drag itself, but not lift itself off the ground. The primitive tetrapod foot has at least 29 bones (35 for the one on the left) laid out in an asymmetrical pattern. There are over 30 joints in each foot below (33 and 34). Each digit of the foot needs at least a ligament for it to be functional. Every joint in the digits has a severely restricted range of motion; they can only bend in one direction. The other joints in the foot have a greater range of motion, but are still restricted in some way; they cannot bend in all directions. The foot has at least 5 sets of joints that could be controlled individually, without affecting the entire appendage. The foot is attached to the skeletal structure, and is capable of supporting the weight of the animal. When the two are compared side-by-side:

	Lungfish Fin Tip-----	Tetrapod Foot
Bones:	8	29-35
Joints:	5	33-34
Joint range of movement:	free or none	highly restricted
Controlability	rough	fine
Structural support:	none	strong

All the stuff above does not prove that the lungfish did not evolve into the first amphibians. However, it does show that lungfish would have to have quite substantial skeletal changes to become amphibians. Lungfish are nowhere near being a conclusive link between fish and amphibians. Had amphibians evolved from fish, it likely would have been through the lungfish. But there would be links. If there was a sequence of similar lungfish that had fins become attached to the skeleton, then develop fibula, tibula, and tibia, then develop ankle bones and multi-segmented proto-digits, that would be worth consideration. That would not even be all the way to an amphibian, but it would be worth considering as evidence. In the chain between the fishes and the amphibians, the lungfish would provide merely a starting point, but any chain between the starting point and the ending point is completely absent.There is no evidence for the evolution of amphibians from lungfish, only speculation.P.S. can an administrator fix all the blank space in here? thanks(added in edit)changed images to ImageShack.Thanks Gary! (/added in edit) I tried hun, two of your images aren't available to link img to, damned geocities sites , can't fix all the space above table...percy will have to let me in on the secret - The Queen[This message has been edited by AdminAsgara, 04-28-2004][This message has been edited by JT, 04-29-2004][This message has been edited by JT, 05-01-2004]

deleted duplicate post - The Queen[This message has been edited by AdminAsgara, 04-28-2004]

Thanks for the compliment.I guess I'll go research mud-skippers...P.S. The Queen...
Thanks for getting rid of some of the whitespace. My computer displays the pictures, I have no clue what that's about. Thanks for adding the links, I'll start doing that

Coragyps,
Is the fin structure of those "Devonian ancestral lungfish" different enough from modern lungfish to make a difference to my argument? Could you post some pictures or links?
thanks
(added in edit) By the way, this picture, which is what I based my argument off of, is of the supposed evolution of amphibians from fish, so the fish fin in the image is of the "ancestral" fish. My argument still stands. Also, which I didn't say earlier (because of a brain fart), this is the standard view of where amphibians came from, so most of what what I was saying applies to the evolution of amphibians in general, independent of the starting species (/added in edit)[This message has been edited by JT, 04-28-2004][This message has been edited by JT, 04-28-2004][This message has been edited by JT, 05-01-2004]

Gary,
Thanks!
I went back and changed my posts, so the images should display now.

Thanks for the help everybody, I think I finally got all the images fixed