Whats wrong with dinosaur reconstruction?

[DariusAmurdarja]

Sorry koltsix. I type on my ipad. Its not so easy to type on that and i would prefer to type on a computer. I will answer your questions, when at home.

 

[koltsixx]

Sorry koltsix. I type on my ipad. Its not so easy to type on that and i would prefer to type on a computer. I will answer your questions, when at home.

Thanx, I'm actually quite curious as you say that this is your field and you should have access to info. that I probably don't. I would enjoy understanding your point of view and perhaps being educated at the same time if my info. is outdated.

 

[Wiggles92]

Most of the scientific community regarding Dino's being coldblooded or warmblooded is split, because the only thing they have to go on for the most part is based on assumed Dino behavior. That and some of the altitudes the fossil's where found at has also created conjecture as no one is sure what the earth was like at those altitudes at that time. Some believe that it was cold so only a endothermic creature could live at that altitude while others say no it was warm and use the proof of vegetation fossilized at that altitude to try and prove it was warmer by far back then compared to today.

Other arguments say Dino's where too big to be endothermic, because at large sizes endothermic creatures essentially burn up due to the stress put on their body by constant thermoregulation. Yet another con against being warm blooded is Dinosaurs lacked respiratory turbinates. To supply their metabolic needs, warm-blooded creatures breathe about five times as often as reptiles. Land-dwelling endotherms have structures in their skulls called “respiratory turbinates,” which help retain moisture during the respiration process. To date, no one has found conclusive evidence of these structures in dinosaur fossils—hence, dinosaurs may have been cold-blooded. Again this is all conjecture, but at least I'm providing reasoning behind my thoughts instead of just making statements and essentially asking people to believe them without any supporting evidence. Can some one please support their argument so I can actually learn something rather than just saying things with no explanation. I'm the only one and now wiggles who I see actually citing actual papers and or providing explanations for thoughts instead of just making unsupported statements.

The problem with the nasal turbinate argument is that bird fossils have not been found to have any nasal turbinates, but we know for a fact that birds are still warm-blooded. We also know that the nasal turbinates are very small or absent in some birds and mammals.

However, I think that at least the Sauropodamorpha were not warm-blooded (endothermic) rather they were cold-blooded (ectothermic) gigantotherms and relied on their large surface area to body mass ratio to maintain a relatively high & stable body temperature.

 

[00rollins]

Most of the scientific community regarding Dino's being coldblooded or warmblooded is split, because the only thing they have to go on for the most part is based on assumed Dino behavior. That and some of the altitudes the fossil's where found at has also created conjecture as no one is sure what the earth was like at those altitudes at that time. Some believe that it was cold so only a endothermic creature could live at that altitude while others say no it was warm and use the proof of vegetation fossilized at that altitude to try and prove it was warmer by far back then compared to today.

Other arguments say Dino's where too big to be endothermic, because at large sizes endothermic creatures essentially burn up due to the stress put on their body by constant thermoregulation. Yet another con against being warm blooded is Dinosaurs lacked respiratory turbinates. To supply their metabolic needs, warm-blooded creatures breathe about five times as often as reptiles. Land-dwelling endotherms have structures in their skulls called “respiratory turbinates,” which help retain moisture during the respiration process. To date, no one has found conclusive evidence of these structures in dinosaur fossils—hence, dinosaurs may have been cold-blooded. Again this is all conjecture, but at least I'm providing reasoning behind my thoughts instead of just making statements and essentially asking people to believe them without any supporting evidence. Can some one please support their argument so I can actually learn something rather than just saying things with no explanation. I'm the only one and now wiggles who I see actually citing actual papers and or providing explanations for thoughts instead of just making unsupported statements.

Interesting and educational. I love factual and theoretical well thought out debate. Cant wait to read a response.

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[koltsixx]

The problem with the nasal turbinate argument is that bird fossils have not been found to have any nasal turbinates, but we know for a fact that birds are still warm-blooded. We also know that the nasal turbinates are very small or absent in some birds and mammals.

However, I think that at least the Sauropodamorpha were not warm-blooded (endothermic) rather they were cold-blooded (ectothermic) gigantotherms and relied on their large surface area to body mass ratio to maintain a relatively high & stable body temperature.

Thanx for the link very informative. I didn't know that some birds don't have them as well as some small mammals. Still if I understood the link correctly it's hard to always find them in fossils as they're very fragile and that's why they may not be found in bird and small mammal fossils and not necessarily because they don't have them. One would assume though that on such a large animal such as a Dino, you'd be more likely to find them since they should be proportionately bigger and less fragile and more likely to be found. So while a definitive hole in the nasal turbinater theory to me it doesn't necessarily rule out it's validity. Still I appreciate the counter perspective. I personally am leaning toward the gigantothermy theory and it ties into my earlier comparison to the Leather back sea turtle. I'm leaning toward it for thera and saura alike. What do you think about the sail/hump? Do you think it was a sail for thermo-regulation or fat or perhaps muscle filled hump as suggested by Darius.

Interesting and educational. I love factual and theoretical well thought out debate. Cant wait to read a response.

Sent from my GT-P7510 using MonsterAquariaNetwork App

Thanx I'm really just a novice in the most extreme sense when it comes to dino's, but it's nice to know that the theoretical info. I supplied was educational and appreciated.

 

[MN_Rebel]

I certainly think that the spines of Spinosaurus could have formed a muscular hump. The common bison (Bison bison) isn't the best example to support your argument in the case of Spinosaurus, though, rather the "ancient bison" (Bison antiquus) or another extinct species would help your case a bit more thanks to their far more pronounced spines (and therefore larger hump).

View attachment 776368

Spinosaurus can't be considered to be an apex predator simply because of their size, though, because they lacked the overall build that would permit them to take on large prey such as sauropods, and a Carcharodontosaurus would have had the advantage if the two had crossed paths due to it being built to take down large prey such as sauropods.

I disagreed with your statement of ancient bison skeleton can be compared to Spinosaurus. Why? Two completely different lifestyle. Ancient bison and other bison species evolved to have a muscular neck/hump to shove out the deep snow to get food. Also Spinosaurus and their relatives' spines were thin and long compared to the bison's thick and robust spines. Of course you have completely forget that there are zero evidence of them have any muscle attrachments on the spines.

 

[DariusAmurdarja]

I disagreed with your statement of ancient bison skeleton can be compared to Spinosaurus. Why? Two completely different lifestyle. Ancient bison and other bison species evolved to have a muscular neck/hump to shove out the deep snow to get food. Also Spinosaurus and their relatives' spines were thin and long compared to the bison's thick and robust spines. Of course you have completely forget that there are zero evidence of them have any muscle attrachments on the spines.

spinosaurus spines are not long and thin but thick and broad. Its not like dimetrodon.

 

[koltsixx]

spinosaurus spines are not long and thin but thick and broad. Its not like dimetrodon.

Your very much correct in the fact that the spines are broad and thick and similar to several animals that had a substantial hump. As far as I know it was Bailey who in 97 suggested that theory. He believed it served as energy storage, insulation, and shielding from heat. Still I agree with it being sail like and being used more for thermo-regulation and perhaps coutrship. I think had a fin very much like a modern day Basilisk.

 

[Lepisosteus platyrhincus]

Your very much correct in the fact that the spines are broad and thick and similar to several animals that had a substantial hump. As far as I know it was Bailey who in 97 suggested that theory. He believed it served as energy storage, insulation, and shielding from heat. Still I agree with it being sail like and being used more for thermo-regulation and perhaps coutrship. I think had a fin very much like a modern day Basilisk.

View attachment 776416

While you are correct the spines are broad, when you consider the shear length of them it becomes apparent that they really arnt. Hopefully that makes since. lol.

MN also pointed out some interesting issues with the comparison between the bison and the spino.

 

[Wiggles92]

Thanx for the link very informative. I didn't know that some birds don't have them as well as some small mammals. Still if I understood the link correctly it's hard to always find them in fossils as they're very fragile and that's why they may not be found in bird and small mammal fossils and not necessarily because they don't have them. One would assume though that on such a large animal such as a Dino, you'd be more likely to find them since they should be proportionately bigger and less fragile and more likely to be found. So while a definitive hole in the nasal turbinater theory to me it doesn't necessarily rule out it's validity. Still I appreciate the counter perspective. I personally am leaning toward the gigantothermy theory and it ties into my earlier comparison to the Leather back sea turtle. I'm leaning toward it for thera and saura alike.

I think that I will defer to two articles from the University of California Museum of Paleontology on this one: "The Evidence for Ectothermy in Dinosaurs" and "The Evidence for Endothermy in Dinosaurs." Both articles provide a lot of great information for both arguments, so it's really tough to say if all dinosaurs are ectotherms or endotherms.

What do you think about the sail/hump? Do you think it was a sail for thermo-regulation or fat or perhaps muscle filled hump as suggested by Darius.

I say that it's for muscles, but I will not rule out the possibility of them being used for thermoregulation. The long spines seem pretty unnecessary for fat storage, so I don't agree with that theory.