Could T Rex skeletons have their arms put on backwards?

[Checkmite]

Yeah, but what can he bench?

I don't think it's been established that he even lifted.

 

[Jrrarglblarg]

The scientist who assemble skeletons of long-extinct species look at very small details on the bones to identify muscle attachment points. Those muscle attachment points indicate where bones are in relation to one another. The arms hang off the shoulder and relative to the spine in the same way yours, my chickens and my dog's forelimbs do. I'm really not understanding what you think is odd or wrong.

 

[Gawdzilla Sama]

The scientist who assemble skeletons of long-extinct species look at very small details on the bones to identify muscle attachment points. Those muscle attachment points indicate where bones are in relation to one another. The arms hang off the shoulder and relative to the spine in the same way yours, my chickens and my dog's forelimbs do. I'm really not understanding what you think is odd or wrong.

http://2.bp.blogspot.com/-x9VN2KjM81E/Tnt5pAyRVTI/AAAAAAAAAfw/uRAuuP5vXA8/s1600/Rex+Arm.jpg

 

[truethat]

Here's an example of what I mean

So what did T. rex do with its not-so-wimpy arms? Paleontologists still aren't precisely sure, but the forelimbs likely served dual purposes for eating and loving. Yes, loving. A key clue comes courtesy of skeletal analysis: It appears that the arms could only swivel a mere 40 degrees at the shoulder and 45 degrees at the elbow. (For reference, humans have 360-degree capabilities at the shoulder and 165 at the elbow.) Such a restriction indicates that the arms were likely only used to grasp objects and hold them in place.

And this bit

"Carnotaurus... had arms that might have not even stuck outside of its body cavity," paleontologist and science writer Brian Switek recently said on Science Friday. "Even Tyrannosaurus rex would laugh at this other dinosaur."

If you look at an EMU it doesn't look strange, nor does a chicken. The body folds into itself. But whenever I've looked at T Rex it's always seemed goofy the way the arms are positioned.

Considering that pretty much no one can figure out what they are used for, I'm asking if it's possible they aren't put on the skeleton the right way.

I'm asking if a biologist or someone who understands what I mean can explain if they cannot be attached a different way. (I fully expected someone by now to say, "No the joint can only fit into the socket ONE way, it's impossible.)

link.

http://www.realclearscience.com/blog/2013/05/t-rex-arms-were-made-for-loving.html

 

[Gawdzilla Sama]

If you accept that the arms dwindled from lack of use over a few million years then the position isn't strange. It would be strange for them to be folded back like a chicken wing, that would be even less useful than the actual position.

 

[truethat]

But it's not useful in the actual position. Everyone's trying to come up with ways it could be useful.

Chickens can fly, but they don't really use their wings. I means wings could be used for fanning. If a dinosaur ate lots of meat, fanning could prevent flies and maggots from growing in the mouth or something.

They could have held ornamental wings, tufts of hair etc. We don't know what they looked like and I'm wondering if there is a simple change that could give us a better idea.

Is there another animal out there with tiny useless arms hanging off it's body?

 

[Gawdzilla Sama]

But it's not useful in the actual position. Everyone's trying to come up with ways it could be useful.

It's not useful because it wasn't used and is diminishing because there's no need for it. If you look at earlier examples of that type of dino you see longer arms. T. rex didn't need to grab things, he had a mouth full of steak knives that did the job nicely.

 

[Trebuchet]

Don't know about the anatomy, but that nekkid rooster is awesome!

 

[Darwin123]

If you accept that the arms dwindled from lack of use over a few million years then the position isn't strange. It would be strange for them to be folded back like a chicken wing, that would be even less useful than the actual position.

If it was used for mating, then maybe not.

Assume that T. rex mated the same way as birds. That is, male behind the female. Note that the T. rex is much larger and heavier than the bird. The scale of T. rex favors gravity over frictional forces. The weight of the T. rex bodies will beat the friction of the surface. Hence, T. rex may need some arms to hold their bodies in place during mating.

Now suppose that the arms could swivel a great deal. The arms during copulation could be on the ventral side for the male and on the dorsal side for the female. The arms would be strong enough to grasp the bodies in the optimal position for copulation. They could reduce the chance of accident. They don't have to be long for this purpose.

However, if the arms swivel so much then they could be laid out on either side when the animal isn't copulating. Both genders could have laid the arms on the ventral side to protection the arms. Since most depictions of T. rex are shown while it is walking or hunting, the artists would still be portraying the arms correctly.

If the arms could really swivel over a very broad a range, there may be more than one 'right answer'. Maybe the arms were multifunctional. They were used for protecting the throat in the ventral position while used for mating in a more dorsal position. The arms were positioned were they would be most useful for a certain function.

The scientists and artists putting T. rex together probably know what they are doing. There is no reason to think they are wrong. However, the arms could swivel. That means that there may be more than one correct answer.

 

[Gawdzilla Sama]

I don't see the geometry working out for mating.

 

[Delvo]

The shoulder sockets point down and out, not back and up, so that's the only way to connect the humeri.

Also, down had always been the default in the ancestors, which had stood on four legs before, and remained so in all of their bipedal flightless cousins, so tyrannosaurs would have needed some specific reason to deviate from that, and there isn't any. (Birds' arms got reworked for flight, but that doesn't apply to flightless lineages.)

 

[snoop_doxie]

I don't see the geometry working out for mating.

No, does not compute for me either.
How did they do it?
(and, why do I need to know this?)

 

[Gawdzilla Sama]

No, does not compute for me either.
How did they do it?
(and, why do I need to know this?)

I think it relates to something Jack Horny Horner may have said.

 

[truethat]

I think it relates to something Jack Horny Horner may have said.

No it doesn't.

It's a legitimate question. What a stupid narrow minded response.

The shoulder sockets point down and out, not back and up, so that's the only way to connect the humeri.

Also, down had always been the default in the ancestors, which had stood on four legs before, and remained so in all of their bipedal flightless cousins, so tyrannosaurs would have needed some specific reason to deviate from that, and there isn't any. (Birds' arms got reworked for flight, but that doesn't apply to flightless lineages.)

Thank you, you've answered my question. Have a great day!

 

[Bram Kaandorp]

Hmm I guess I'm not understanding or explaining myself well. Is it physically possible for the bone to sit in the socket twisted the other way around like little wings.

Are you asking if the arm could have been positioned differently than that of a chicken so that it would resemble a chicken's positioning more on a superficial level?

Could the Trex look more like the picture of the chicken rather than the dangling appendages in standard pictures. The hanging arms just always look weird to me. But if it is possible it could have sat more like a wing does, (not saying it was a wing) then maybe the claws jutted out to protect his neck or as Dinwar said served a different purpose.

Dinwar said nothing. He hasn't been in this thread. That would be Darwin123.

It just seems to me that they are out of place as they are positioned now.

Intuition is not always the best guide for how a skeleton should be positioned.

 

[snoop_doxie]

I think it relates to something Jack Horny Horner may have said.

Little Jack Horner?
Sat in a corner?
Eating his curds and whey...hmm that doesn't sound right.
?
Stuck in his thumb, pulled out a plum
And said, "oh what a good boy am I?

How would he know about how T-Rex made little T-Rexs?

 

[Delvo]

I think it relates to something Jack Horny Horner may have said.

Well, that was why they made him go sit in his corner.

Intuition is not always the best guide for how a skeleton should be positioned.

This reminds me of the saga of the ceratopsians. When people first started digging them up, it was clear that they stood upright like mammals & birds, and that's how the first drawings & mountings were done. Then a religion/philosophy-based approach demanded that anything that had to go extinct to make way for "us" (mammals) must have been "inferior", and that dinosaurs must have fit neatly into the established category "reptiles" because they had diapsid skull structure and clearly weren't birds and you just couldn't have whole new categories.

So for a while, dinosaurs were essentially required to be depicted as slow, weak, and dim, including in ways that clearly violated basic anatomy. (And we're not just talking about technicalities you need to study to learn, like how to assemble skeletons and articulate joints, but even stupidly obvious stuff like the fact that if you splay out a sauropod's legs lizard-style then its ribs extend underground and if a huge animal dragged its tail on the ground then its tracks would include a tailprint as well as footprints. That didn't stop these folks.) Thus, ceratopsians got their shoulders & hips dislocated to put them in a philosophically appropriately lizardy stance. When people started objecting to that because it went against what the animals' anatomy had clearly been telling us all along, some museums compromised by straightening up the pair of legs for which the problem was more obvious, the rear legs, while still leaving the front legs down for years to come! (Not anymore at any museum I'm aware of, though.)

 

[truethat]

Well, that was why they made him go sit in his corner.

This reminds me of the saga of the ceratopsians. When people first started digging them up, it was clear that they stood upright like mammals & birds, and that's how the first drawings & mountings were done. Then a religion/philosophy-based approach demanded that anything that had to go extinct to make way for "us" (mammals) must have been "inferior", and that dinosaurs must have fit neatly into the established category "reptiles" because they had diapsid skull structure and clearly weren't birds and you just couldn't have whole new categories.

So for a while, dinosaurs were essentially required to be depicted as slow, weak, and dim, including in ways that clearly violated basic anatomy. (And we're not just talking about technicalities you need to study to learn, like how to assemble skeletons and articulate joints, but even stupidly obvious stuff like the fact that if you splay out a sauropod's legs lizard-style then its ribs extend underground and if a huge animal dragged its tail on the ground then its tracks would include a tailprint as well as footprints. That didn't stop these folks.) Thus, ceratopsians got their shoulders & hips dislocated to put them in a philosophically appropriately lizardy stance. When people started objecting to that because it went against what the animals' anatomy had clearly been telling us all along, some museums compromised by straightening up the pair of legs for which the problem was more obvious, the rear legs, while still leaving the front legs down for years to come! (Not anymore at any museum I'm aware of, though.)

That's exactly the reason I asked the question.

 

[Gawdzilla Sama]

No it doesn't.

It's a legitimate question. What a stupid narrow minded response.

Your sense of humor called, it misses you.

 

[CORed]

They're not similar. At least not in any respect other than being short, and that is based on the same of a flightless bird that was breed to have short wings so it wouldn't fly the coop, literally.

Chickens are not flightless birds. They are, however, short distance flyers. Domestic chickens are frequently rendered flightless by clipping feathers off of one wing.