Tyrannosaurus in the wetlands

[studiot]

6 hours ago, martillo said:

Ok, I must admit that my proposition seems inviable in several ways. It was just an idea on my head that I needed to resolve...

I meant to say +1 for reaching this conclusion for yourself and admitting it online.

3 hours ago, martillo said:

So the T Rex living in the wetlands could be not a bad idea afterall.

But he definitely could not completely immerse in water for hunting.

I think the main advantage in a T Rex being a semi aquatic or amphibious animal is that he could lean his big and heavy body on the water. Could be possible then to think in a T Rex leaning and sliding on shallow waters hiding by some dense vegetation sometimes?

Remember that a T Rex needs a lot of food so will either have to hunt a lot of small game or some very big game.

So it will hang about well stocked places. That is places that are also good for other creatures, perhaps plant eaters.
So the lush areas of the planet.

[martillo]

20 minutes ago, studiot said:

Remember that a T Rex needs a lot of food so will either have to hunt a lot of small game or some very big game.

So it will hang about well stocked places. That is places that are also good for other creatures, perhaps plant eaters.
So the lush areas of the planet.

The "Pantanal" region I have mentioned is very lush in vegetation (wikipedia):

10 hours ago, martillo said:

"Roughly 80% of the Pantanal floodplains are submerged during the rainy seasons, nurturing a biologically diverse collection of aquatic plants and helping to support a dense array of animal species."

"The Pantanal ecosystem is home to some 463 species of birds,^[5] 269 species of fishes, more than 236 species of mammals,^[12] 141 species of reptiles and amphibians, and over 9,000 subspecies of invertebrates."

 

Edited October 29, 2023 by martillo

[studiot]

 

34 minutes ago, martillo said:

The "Pantanal" region I have mentioned is very lush in vegetation (wikipedia):

 

Even with the latest ideas as to the age of the Andes, they are less than 20 million years old.

 

So that part of South Americal has changed significantly since say 100 mya.

 

But yes, such a region would have supported lots of food species.

[martillo]

58 minutes ago, studiot said:

 

Even with the latest ideas as to the age of the Andes, they are less than 20 million years old.

 

So that part of South Americal has changed significantly since say 100 mya.

 

But yes, such a region would have supported lots of food species.

I know the T Rex belonged to North America about 68-66 millions years ago. I have mentioned current "Pantanal" region just as an example of how could have been an appropriated region for the T Rex in his days at North America. North America seems to had a more "tropical" clima than nowadays at that age.

From "Cretaceous" at Wikipedia (https://en.wikipedia.org/wiki/Cretaceous): 

"The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice-free, and forests extended to the poles. During this time, new groups of mammals and birds appeared."

Edited October 29, 2023 by martillo

[Moontanman]

The Main impediment "IMHO" to a amphibious T-Rex is the carnivores it would have to compete with. The wetlands were not empty places just waiting to be exploited by a big predator. There were giant sized crocodilians that lived in those wetlands, crocodiles more than big enough to take down a T-Rex... in fact they probably were a big danger to a T-rex trying to take a drink from a waterway BITD (back in the day) You have to remember that Crocodiles are powerful predators, well adapted to their environment, exothermic, so their food intake was lower than a exothermic T-Rex. Unlike a T-Rex Crocodiles can go long periods without food and so can afford, metabolically, to sit and wait for food to come to them. A T-Rex with its bird like metabolism had to eat much more and to go out and hunt down large prey items on a regular basis. A T-Rex wes adapted to hunting down prey and was probably fast enough to do so with its huge muscular hind legs.  

T-Rex was not well suited to semi aquatic living in its body plan, it's metabolism, or its behaviors and was as vulnerable as any other land creature to the true dominating predators of the wetlands... Crocodiles. 

[martillo]

1 hour ago, Moontanman said:

The Main impediment "IMHO" to a amphibious T-Rex is the carnivores it would have to compete with. The wetlands were not empty places just waiting to be exploited by a big predator. There were giant sized crocodilians that lived in those wetlands, crocodiles more than big enough to take down a T-Rex... in fact they probably were a big danger to a T-rex trying to take a drink from a waterway BITD (back in the day) You have to remember that Crocodiles are powerful predators, well adapted to their environment, exothermic, so their food intake was lower than a exothermic T-Rex. Unlike a T-Rex Crocodiles can go long periods without food and so can afford, metabolically, to sit and wait for food to come to them. A T-Rex with its bird like metabolism had to eat much more and to go out and hunt down large prey items on a regular basis. A T-Rex wes adapted to hunting down prey and was probably fast enough to do so with its huge muscular hind legs.  

T-Rex was not well suited to semi aquatic living in its body plan, it's metabolism, or its behaviors and was as vulnerable as any other land creature to the true dominating predators of the wetlands... Crocodiles. 

All hunters need to compete with other hunters in nature but they find a way for existing, isn't it? Fighting sometimes happens but even those which would lose still exist. That is not a reason for the T Rex not being an amphibious one.

A question: I know about giant crocodiles but I thought that was in the seas. Are you sure so big crocodiles as you mention have existed at the not so deep wetlands? Doesn't seem so.

Edited October 30, 2023 by martillo

[studiot]

59 minutes ago, Moontanman said:

The Main impediment "IMHO" to a amphibious T-Rex is the carnivores it would have to compete with. The wetlands were not empty places just waiting to be exploited by a big predator. There were giant sized crocodilians that lived in those wetlands, crocodiles more than big enough to take down a T-Rex... in fact they probably were a big danger to a T-rex trying to take a drink from a waterway BITD (back in the day) You have to remember that Crocodiles are powerful predators, well adapted to their environment, exothermic, so their food intake was lower than a exothermic T-Rex. Unlike a T-Rex Crocodiles can go long periods without food and so can afford, metabolically, to sit and wait for food to come to them. A T-Rex with its bird like metabolism had to eat much more and to go out and hunt down large prey items on a regular basis. A T-Rex wes adapted to hunting down prey and was probably fast enough to do so with its huge muscular hind legs.  

T-Rex was not well suited to semi aquatic living in its body plan, it's metabolism, or its behaviors and was as vulnerable as any other land creature to the true dominating predators of the wetlands... Crocodiles. 

Yes that is one hypothesis, thought some references would have been nice.

 

Here are some

A bit of a sensationalist site

https://www.syfy.com/syfy-wire/ancient-terror-crocodile-deinosuchus-ate-dinosaurs

 

and a more measure one

 

https://en.wikipedia.org/wiki/Deinosuchus

 

Note that both refer only to supposition, not hard evidence.

 

But both sites refer to older ideas about cretaceous environemntal conditions, although the central N. american shallow sea was mentioned.

 

I suggest that the skin of a creature that spends most of its time largely submerged would need to have differences from that of a creature that spends most of its time in the open air.

 

The most modern reconstructions by respectively Lascouara (Dakota) Attenborough (UK) and Packham (UK) suggest some differences including the intriguing question

Were the flying dinosaurs beginning to dominate before the end , especially as it is known that sea levels were rising duting this period.

 

These can all be seen from the BBC

'The Day the Dinosaurs Died' presented by Roberts and Garrod

'Earth' presented by Cchris Packham

'The Final Day' presented by David Attenborough

[Moontanman]

21 hours ago, martillo said:

All hunters need to compete with other hunters in nature but they find a way for existing, isn't it? Fighting sometimes happens but even those which would lose still exist. That is not a reason for the T Rex not being an amphibious one.

For the same reason lions do not spend much time hunting in water occupied by crocodiles nor do crocodiles hunt on land occupied by lions. Large carnivores do not fight, populations compete with each other over resources and habitats. Yes individuals occasionally interact but it's the overall competition between them over resources that limit their occupation of habitats. So far you have given no reason to think a T-Rex would would want to take up a lifestyle it is obviously not adapted to anymore than crocodiles would decide to take up hunting zebras on the grasslands.

 

21 hours ago, martillo said:

A question: I know about giant crocodiles but I thought that was in the seas. Are you sure so big crocodiles as you mention have existed at the not so deep wetlands? Doesn't seem so.

https://en.wikipedia.org/wiki/Deinosuchus

Edited October 31, 2023 by Moontanman

[martillo]

3 hours ago, Moontanman said:

For the same reason lions do not spend much time hunting in water occupied by crocodiles nor do crocodiles hunt on land occupied by lions. Large carnivores do not fight, populations compete with each other over resources and habitats. Yes individuals occasionally interact but it's the overall competition between them over resources that limit their occupation of habitats. So far you have given no reason to think a T-Rex would would want to take up a lifestyle it is obviously not adapted to anymore than crocodiles would decide to take up hunting zebras on the grasslands.

 

https://en.wikipedia.org/wiki/Deinosuchus

From Wikipedia:

Deinosuchus: "Using more complete remains, it was estimated in 1999 that the size attained by specimens of Deinosuchus varied from 8 to 10 meters (26 to 33 ft) with weights from 2.5 to 5 metric tons (2.8 to 5.5 short tons).^[15]"

Tyrannosaurus: "The most complete specimen measures up to 12.3–12.4 m (40–41 ft) in length, but according to most modern estimates, Tyrannosaurus could have exceeded sizes of 12.4 m (41 ft) in length, 3.7–4 m (12–13 ft) in hip height, and 10 tonnes (9.8 long tons; 11 short tons) in mass."

In a fight of both I would surely bet on the T Rex!

And I think Tyrannosaurus could be well adapted to live in grass-flooded areas. Not immersed, I agree now, just leaning his so heavy body on the water and sliding on it pushed by his strong legs and feet. Yes, I can quite "see" them in that lifestyle of a total ape predator on those areas...

Edited October 31, 2023 by martillo

[martillo]

This is quite what I'm talking about:

(from a page of National geographic in Spanish I have just found: https://www.nationalgeographic.com.es/ciencia/unas-huellas-fosiles-encontradas-rioja-revelan-que-algunos-dinosaurios-podian-nadar_20929) 

This is a spinosaurus not a tyrannosaurus of course but well illustrates my point of view.

Edited October 31, 2023 by martillo

[Moontanman]

1 hour ago, martillo said:

This is quite what I'm talking about:

(from a page of National geographic in Spanish I have just found: https://www.nationalgeographic.com.es/ciencia/unas-huellas-fosiles-encontradas-rioja-revelan-que-algunos-dinosaurios-podian-nadar_20929) 

This is a spinosaurus not a tyrannosaurus of course but well illustrates my point of view.

As you said this is a spinosaurus not a T-Rex, compare the two then get back to me. 

2 hours ago, martillo said:

From Wikipedia:

Deinosuchus: "Using more complete remains, it was estimated in 1999 that the size attained by specimens of Deinosuchus varied from 8 to 10 meters (26 to 33 ft) with weights from 2.5 to 5 metric tons (2.8 to 5.5 short tons).^[15]"

Tyrannosaurus: "The most complete specimen measures up to 12.3–12.4 m (40–41 ft) in length, but according to most modern estimates, Tyrannosaurus could have exceeded sizes of 12.4 m (41 ft) in length, 3.7–4 m (12–13 ft) in hip height, and 10 tonnes (9.8 long tons; 11 short tons) in mass."

In a fight of both I would surely bet on the T Rex!

And I think Tyrannosaurus could be well adapted to live in grass-flooded areas. Not immersed, I agree now, just leaning his so heavy body on the water and sliding on it pushed by his strong legs and feet. Yes, I can quite "see" them in that lifestyle of a total ape predator on those areas...

Size has little to do with this, a T-Rex in water is about as helpless to large water carnivore as an elephant is to a great white shark. Elephants can swim more than 30 miles and can stay in the water for many hours but they are not going to try and take habitat away from dugongs just because elephants are bigger. 

You are aware that a T-Rex is, metabolically, akin to birds (they even had feathers)... an endotherm that needs but lacks the traits that makes crocodiles such successful predators in their cool watery habitats. Crocodiles are endotherms, need far less food and can afford to waits for days and or weeks and months between feedings... right? Spinosaurus was a totally different animal, shaped more like a crocodile and only some were adapted to a watery habitat and even that is still debated. Spinosaurus has been redesigned so many times and at this time is considered to have been a quadruped adapted to a lifestyle very similar to the quadruped crocodiles while T-Rex was a biped with almost nonexistent front limbs.  

Edited October 31, 2023 by Moontanman

[martillo]

59 minutes ago, Moontanman said:

As you said this is a spinosaurus not a T-Rex, compare the two then get back to me. 

Size has little to do with this, a T-Rex in water is about as helpless to large water carnivore as an elephant is to a great white shark. Elephants can swim more than 30 miles and can stay in the water for many hours but they are not going to try and take habitat away from dugongs just because elephants are bigger. 

You are aware that a T-Rex is, metabolically, akin to birds (they even had feathers)... an endotherm that needs but lacks the traits that makes crocodiles such successful predators in their cool watery habitats. Crocodiles are endotherms, need far less food and can afford to waits for days and or weeks and months between feedings... right? Spinosaurus was a totally different animal, shaped more like a crocodile and only some were adapted to a watery habitat and even that is still debated. Spinosaurus has been redesigned so many times and at this time is considered to have been a quadruped adapted to a lifestyle very similar to the quadruped crocodiles while T-Rex was a biped with almost nonexistent front limbs.  

I think in a long path of evolution from a swimming aquatic lifestyle to after walking land lifestyles and yet after flying air lifestyles. I could think in tyrannosaurus as an amphibious descendant of crocodiles adapting to the walking land lifestyle for instance. Of course several branches of descendants could be opened from crocodiles. Tyrannosaurus could be just one of them I think. Why not to think in such possibility? Seems a very natural one.

Edited October 31, 2023 by martillo

[studiot]

15 minutes ago, martillo said:

Tyrannosaurus could be just one of them I think. Why not to think in such possibility? Seems a very natural one.

I think we should look at our best information and let those skilled in genealagy trees guide us rather than just guessing and always be prepared to make radical changes.

There have been many wrong connections drawn in the past.

[martillo]

48 minutes ago, studiot said:

I think we should look at our best information and let those skilled in genealagy trees guide us rather than just guessing and always be prepared to make radical changes.

There have been many wrong connections drawn in the past.

Genealogy trees experts are welcome. Which are currently considered the ancestors of the tyrannosaurus? Thinking in the line of evolution from water to land of living beings...

Edited October 31, 2023 by martillo

[martillo]

1 hour ago, martillo said:

I think in a long path of evolution from a swimming aquatic lifestyle to after walking land lifestyles and yet after flying air lifestyles. I could think in tyrannosaurus as an amphibious descendant of crocodiles adapting to the walking land lifestyle for instance. Of course several branches of descendants could be opened from crocodiles. Tyrannosaurus could be just one of them I think. Why not to think in such possibility? Seems a very natural one.

Seems that was a silly thought... Looking on "archosaurs" at Wikipedia (https://en.wikipedia.org/wiki/Archosaur) now...

Edited October 31, 2023 by martillo

[martillo]

I understand now that the path of evolution from a swimming aquatic lifestyle to after walking land lifestyles have happened at much earlier ages in the evolution of the life in the planet with much more primitive beings than I thought.

The real problem I have with the T Rex, which is the cause oh having posted this thread, is a visual one. Looking at any image made of the T Rex my perception is that it present too much weigh in the front of the legs than in the back of them. It is said everywhere that the T Rex walked on two legs using the tail for balance. In my visual perception the shown tail would not be enough to achieve the balance with that so big head the T Rex has. That's why I like to think in the T Rex as an amphibious more likely to be in the water most of the time. But it must be a problem of my perception. I assume now that this subject has been already studied deep enough and that would not be the case. 

[studiot]

I note in your classification tree article the Michael Benson is mentioned,

His book is fascinating.

Quote

n 1988, paleontologists Michael Benton and J.M. Clark produced a new tree in a phylogenetic study of basal archosaurs. As in Gauthier's tree, Benton and Clark's revealed a basal split within Archosauria. They referred to the two groups as Crocodylotarsi and Ornithosuchia. Crocodylotarsi was defined as an apomorphy-based taxon based on the presence of a "crocodile-normal" ankle joint (considered to be the defining apomorphy of the clade). Gauthier's Pseudosuchia, by contrast, was a stem-based taxon. Unlike Gauthier's tree, Benton and Clark's places Euparkeria outside Ornithosuchia and outside the crown group Archosauria altogether.^[28]

From it I learned that not only was the mass extinction of the dinosaurs not the worst mass extinction in Earth's history, but that the previous inhabitants that were wiped out in the biggest mass extinction (at the end of the Permian) were every bit as big,  dominant and successful as the dinosaurs. They are called dicynodonts.

https://en.wikipedia.org/wiki/Dicynodont

 

These were often confused/ mixed up with the dinosaurs in classification schemes although they lived (and died) 60 million years before the first dinosaurs.

 

Not also that genealogy tracing is very difficult for all these as we only have a few samples of DNA so most  trees are classification schemes, rather than acestry diagrams.
As such they are constantly being revised as new data appears.

 

 

[Moontanman]

18 hours ago, martillo said:

I think in a long path of evolution from a swimming aquatic lifestyle to after walking land lifestyles and yet after flying air lifestyles. I could think in tyrannosaurus as an amphibious descendant of crocodiles adapting to the walking land lifestyle for instance. Of course several branches of descendants could be opened from crocodiles. Tyrannosaurus could be just one of them I think. Why not to think in such possibility? Seems a very natural one.

You can speculate anything you want but if you are going to tear down a complete evolutionary tree I think you need to find out a little about the evolutionary history of life on Earth. T-Rex was not a crocodile, T-Rex was a Dinosaur, both are archosaurs, but crocodiles are not Dinosaurs. The last common ancestor of both existed before there were either. 

[TheVat]

The dates are fairly precise.  T. Rex began in 1967, the Crocodiles began in 2008.  

[martillo]

1 hour ago, Moontanman said:

You can speculate anything you want but if you are going to tear down a complete evolutionary tree I think you need to find out a little about the evolutionary history of life on Earth. T-Rex was not a crocodile, T-Rex was a Dinosaur, both are archosaurs, but crocodiles are not Dinosaurs. The last common ancestor of both existed before there were either. 

No, no, I have been changing my mind on the subject. I have already commented that it was a silly thought of mine:

18 hours ago, martillo said:

Seems that was a silly thought... Looking on "archosaurs" at Wikipedia (https://en.wikipedia.org/wiki/Archosaur) now...

And after looking at the tree and some other searches I arrived to:

5 hours ago, martillo said:

I understand now that the path of evolution from a swimming aquatic lifestyle to after walking land lifestyles have happened at much earlier ages in the evolution of the life in the planet with much more primitive beings than I thought.

My last thinking is now the following:

5 hours ago, martillo said:

The real problem I have with the T Rex, which is the cause oh having posted this thread, is a visual one. Looking at any image made of the T Rex my perception is that it present too much weigh in the front of the legs than in the back of them. It is said everywhere that the T Rex walked on two legs using the tail for balance. In my visual perception the shown tail would not be enough to achieve the balance with that so big head the T Rex has. That's why I like to think in the T Rex as an amphibious more likely to be in the water most of the time. But it must be a problem of my perception. I assume now that this subject has been already studied deep enough and that would not be the case. 

 

36 minutes ago, TheVat said:

The dates are fairly precise.  T. Rex began in 1967, the Crocodiles began in 2008.  

May be a joke but I didn't get it...

Edited November 1, 2023 by martillo

[mistermack]

5 hours ago, martillo said:

That's why I like to think in the T Rex as an amphibious more likely to be in the water most of the time.

I think that idea is a non-starter. Wading about on two feet in water is extremely cumbersome for a big animal. Birds can do it, but they are small, lightweight and have wings to balance with. A water living dinosaur would have evolved bigger feet and a flattened tail for propulsion, as in crocodiles. There's been plenty of work done on T Rex locomotion, and the balance has never been an issue. The latest analytical work seem to suggest that the held the body more horizontally than earlier thought, and the tail was stretched out horizontally behind for balance. 

[martillo]

5 minutes ago, mistermack said:

I think that idea is a non-starter. Wading about on two feet in water is extremely cumbersome for a big animal. Birds can do it, but they are small, lightweight and have wings to balance with. A water living dinosaur would have evolved bigger feet and a flattened tail for propulsion, as in crocodiles. There's been plenty of work done on T Rex locomotion, and the balance has never been an issue. The latest analytical work seem to suggest that the held the body more horizontally than earlier thought, and the tail was stretched out horizontally behind for balance. 

Thanks for the clarification. I'm realizing it is a problem with my visual perception only...

[swansont]

6 hours ago, martillo said:

The real problem I have with the T Rex, which is the cause oh having posted this thread, is a visual one. Looking at any image made of the T Rex my perception is that it present too much weigh in the front of the legs than in the back of them.

A T. rex that was about 4 m tall, would be about 13 m long. The length of the tail factors into the torque, as well as the mass.

[martillo]

13 minutes ago, swansont said:

A T. rex that was about 4 m tall, would be about 13 m long. The length of the tail factors into the torque, as well as the mass.

Yes, is that visually for me the tail could not compensate well his big head but seems a problem in my perception only. I'm assuming now that this subject has already been analyzed deep enough even with digital simulation procedures on the mass, forces, weight, torque, etc. I'm realizing now that my speculation actually would not work. Thanks for the comment.

Edited November 1, 2023 by martillo

[mistermack]

I would say that I agree that most depictions of T Rex do look front-end-heavy. But I think that maybe that comes from the fact that most of the tail was muscle, not bone, so the fossils might give a misleading impression of how bulky the tail actually was. Also, the lungs were hollow, so that part looks heavier than it was. 

Here's a lizard running on two legs. The tail is not very bulky, and he's fairly upright, with the tail stretched out. Maybe T Rex did the same, or maybe it had a bulkier tail. I would opt for the latter.