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04-30-2022, 04:14 AM( This post was last modified: 04-30-2022, 04:35 AM by LonePredator )
(04-30-2022, 04:00 AM)tigerluver Wrote:
(04-30-2022, 03:14 AM)LonePredator Wrote:
(04-30-2022, 03:09 AM)tigerluver Wrote:
(04-30-2022, 02:18 AM)LonePredator Wrote:
(04-30-2022, 02:10 AM)tigerluver Wrote:
(04-29-2022, 02:41 AM)LonePredator Wrote:
(04-29-2022, 02:33 AM)tigerluver Wrote:
(04-28-2022, 10:05 PM)LonePredator Wrote: @tigerluver How did they estimate the size of Smilodon Populator when it was so different from currently living felids? Like it’s morphology was entirely different from the living cats.
Can you tell me the equations which has been used for it and are all these allometric equations similar in different kinds of uses? For example, is an allometric equation to find the weight of smilodon populator similar to say Cave Bear? Can you tell me a little bit about this?
You make an excellent observation and truly, no publication has really been able to address the limitation.
The oldest estimates from Anyonge used circumferences of the long bones. Christiansen and Harris (2005) did similar but also added many other dimensions of the bone. Both used extant felids as the source of the regression equations and cannot actually account for the unique proportions of Smilodon. The hope is that circumference has minimal interspecific different in estimating body mass in these. While Campione et al. (2012) did show circumference is best correlated with body mass across taxa, the percent error is still actually quite significant. Another example of the problem of Smilodon is that it is front heavy, therefore there is a comparatively disproportionate amount of weight supported by the forelimbs as compared to hindlimbs (while in extant cats the distribution is more even). If we think about this theoretically, this would result in the humerus robusticity overestimating (a greater percentage of the body weight is stressing the forelimbs, so they will be proportionately thicker for the total weight) while femur robusticity (a lesser percentage of the body weight is stressing the hindlimbs, so they would be proportionately thinner for the body weight) would underestimate.
The allometric equations were based on felids. Separate equations have been made for bears. When we compare the estimates from the equations, the results are different. This means an allometric equation applied to a felid cannot really apply accurately to a bear.
The giant Smilodon skull was estimated using a regression developed from felid skulls. The issue here is that Smilodon had a smaller skull for its body as compared to extant felids. Therefore, this estimate is probably a significant underestimate.
So there is no perfect formula for Smilodon. Volumetric estimation can be attempted but it gets exposed to subjectivity as the model is essentially art subject to the artist's thoughts.
Thankyou very much. A very well detailed explanation. I will check out those sources. As far as I remember, I think that the oldest estimates which came from Anyonge were gross overestimations.
Just one more question, do you think that the isometric scaling of extant felids by scaling the the mass cubically in relation to scaling the length linearly give an accurate enough bodymass estimate? I’m aware it’s just a law of physics which only works on objects of similar proportions but...
What if I do the same for the shoulder height, chest girth and head body length. I linearly scale all these dimensions to the dimensions of the big Tiger and then cubically scale the mass and then average out all the three mass estimates then will it practically hold up?
Do you think that will give a good enough estimate of the mass of the big Tiger and can you roughly predict a percentage error that I could get in my result?
And once again, thanks a lot for your detailed explaination.
Isometry is the most parsimonious when are comparing animals of the same species so I prefer it.
Isometry works with 3 dimensions (length, width, height). Therefore, if you use three measurements that are surrogates for these dimensions, cubically scale the mass, then average them together, you should get an estimate that ideally accurately estimates the mass/volume. There is no real way to calculate percent error unfortunately.
Another way to do it is to multiple the difference ratio of length by the difference ratio of width and the difference ratio of height. This is based on the formula for volume (length * width * height). For instance, if a tiger is 1.2x longer, 1.1x width, and 1.4x taller than another tiger, you would do:
Mass bigger tiger = Mass smaller tiger * (1.2 * 1.1 * 1.4) = Mass smaller tiger * 2.002
This way is mathematically more accurate than averages the cubically scaled masses together.
This makes it much more simpler. Thanks a lot! I was calculating with all three dimensions separately and then averaging them out and even though it was working well, I’ll try this out now.
Just one more question. I’ve seen in some studies which show that the bite force of Jaguar is 3/4th that of a Bengal Tiger while the bodymass of the Jaguar is only half of the Tiger.
But can we really say that Jaguar has pound for pound stronger bite? Because when we scale the Jaguar to the same weight as the Tiger (by 2x) then the bite force would only increase by 1.777 times, right? Because the cross sectional area would only increase by an exponent of 2 while the mass increases by an exponent of 3.
And I calculated this and found that when mass of the Jaguar is scaled to 200kg from 100 then the force would still be about 12% weaker. Don’t you also think that the Jaguar would still have a weaker bite force than the Tiger if we scale a Jaguar by 2 times to make it equal in weight as the Tiger??
In the literal sense your math would be right. However, as skulls get bigger there are allometric effects such as increase in the length of the masseteric fossa which would increase the bite force.
Therefore, regressions are made to account for the allometric changes. Wroe et al. finds the jaguar's bite force is above the regression line:
*This image is copyright of its original author
The positioning of where the point is as compared to the regression line is measured by the bite force quotient (BFQ). In the study, the jaguar's BFQ is 1.37 and the tiger's 1.27. A weakness of the study is that actual weights of animals are not used, just estimates. Therefore, the BFQ may not be accurate.
A more fruitful measurement would probably be bite force over skull length. I ran the regression quickly (can't figure out how to label datapoints, if I have time later I will update the post):
*This image is copyright of its original author
Based on the second graph, the jaguar has significantly stronger bite than predicted for its skull length.
Is this allometric variation seen in the Jaguars? I mean do the bigger Jaguar skulls have these allometric variations compared to the smaller Jaguar species of the same population.
I haven't seen enough jaguar skulls but I see the trend in tigers and lions, so I infer it's also in jaguars.
(04-30-2022, 03:14 AM)LonePredator Wrote:
(04-30-2022, 03:09 AM)tigerluver Wrote:
(04-30-2022, 02:18 AM)LonePredator Wrote:
(04-30-2022, 02:10 AM)tigerluver Wrote:
(04-29-2022, 02:41 AM)LonePredator Wrote:
(04-29-2022, 02:33 AM)tigerluver Wrote:
(04-28-2022, 10:05 PM)LonePredator Wrote: @tigerluver How did they estimate the size of Smilodon Populator when it was so different from currently living felids? Like it’s morphology was entirely different from the living cats.
Can you tell me the equations which has been used for it and are all these allometric equations similar in different kinds of uses? For example, is an allometric equation to find the weight of smilodon populator similar to say Cave Bear? Can you tell me a little bit about this?
You make an excellent observation and truly, no publication has really been able to address the limitation.
The oldest estimates from Anyonge used circumferences of the long bones. Christiansen and Harris (2005) did similar but also added many other dimensions of the bone. Both used extant felids as the source of the regression equations and cannot actually account for the unique proportions of Smilodon. The hope is that circumference has minimal interspecific different in estimating body mass in these. While Campione et al. (2012) did show circumference is best correlated with body mass across taxa, the percent error is still actually quite significant. Another example of the problem of Smilodon is that it is front heavy, therefore there is a comparatively disproportionate amount of weight supported by the forelimbs as compared to hindlimbs (while in extant cats the distribution is more even). If we think about this theoretically, this would result in the humerus robusticity overestimating (a greater percentage of the body weight is stressing the forelimbs, so they will be proportionately thicker for the total weight) while femur robusticity (a lesser percentage of the body weight is stressing the hindlimbs, so they would be proportionately thinner for the body weight) would underestimate.
The allometric equations were based on felids. Separate equations have been made for bears. When we compare the estimates from the equations, the results are different. This means an allometric equation applied to a felid cannot really apply accurately to a bear.
The giant Smilodon skull was estimated using a regression developed from felid skulls. The issue here is that Smilodon had a smaller skull for its body as compared to extant felids. Therefore, this estimate is probably a significant underestimate.
So there is no perfect formula for Smilodon. Volumetric estimation can be attempted but it gets exposed to subjectivity as the model is essentially art subject to the artist's thoughts.
Thankyou very much. A very well detailed explanation. I will check out those sources. As far as I remember, I think that the oldest estimates which came from Anyonge were gross overestimations.
Just one more question, do you think that the isometric scaling of extant felids by scaling the the mass cubically in relation to scaling the length linearly give an accurate enough bodymass estimate? I’m aware it’s just a law of physics which only works on objects of similar proportions but...
What if I do the same for the shoulder height, chest girth and head body length. I linearly scale all these dimensions to the dimensions of the big Tiger and then cubically scale the mass and then average out all the three mass estimates then will it practically hold up?
Do you think that will give a good enough estimate of the mass of the big Tiger and can you roughly predict a percentage error that I could get in my result?
And once again, thanks a lot for your detailed explaination.
Isometry is the most parsimonious when are comparing animals of the same species so I prefer it.
Isometry works with 3 dimensions (length, width, height). Therefore, if you use three measurements that are surrogates for these dimensions, cubically scale the mass, then average them together, you should get an estimate that ideally accurately estimates the mass/volume. There is no real way to calculate percent error unfortunately.
Another way to do it is to multiple the difference ratio of length by the difference ratio of width and the difference ratio of height. This is based on the formula for volume (length * width * height). For instance, if a tiger is 1.2x longer, 1.1x width, and 1.4x taller than another tiger, you would do:
Mass bigger tiger = Mass smaller tiger * (1.2 * 1.1 * 1.4) = Mass smaller tiger * 2.002
This way is mathematically more accurate than averages the cubically scaled masses together.
This makes it much more simpler. Thanks a lot! I was calculating with all three dimensions separately and then averaging them out and even though it was working well, I’ll try this out now.
Just one more question. I’ve seen in some studies which show that the bite force of Jaguar is 3/4th that of a Bengal Tiger while the bodymass of the Jaguar is only half of the Tiger.
But can we really say that Jaguar has pound for pound stronger bite? Because when we scale the Jaguar to the same weight as the Tiger (by 2x) then the bite force would only increase by 1.777 times, right? Because the cross sectional area would only increase by an exponent of 2 while the mass increases by an exponent of 3.
And I calculated this and found that when mass of the Jaguar is scaled to 200kg from 100 then the force would still be about 12% weaker. Don’t you also think that the Jaguar would still have a weaker bite force than the Tiger if we scale a Jaguar by 2 times to make it equal in weight as the Tiger??
In the literal sense your math would be right. However, as skulls get bigger there are allometric effects such as increase in the length of the masseteric fossa which would increase the bite force.
Therefore, regressions are made to account for the allometric changes. Wroe et al. finds the jaguar's bite force is above the regression line:
*This image is copyright of its original author
The positioning of where the point is as compared to the regression line is measured by the bite force quotient (BFQ). In the study, the jaguar's BFQ is 1.37 and the tiger's 1.27. A weakness of the study is that actual weights of animals are not used, just estimates. Therefore, the BFQ may not be accurate.
A more fruitful measurement would probably be bite force over skull length. I ran the regression quickly (can't figure out how to label datapoints, if I have time later I will update the post):
*This image is copyright of its original author
Based on the second graph, the jaguar has significantly stronger bite than predicted for its skull length.
And was this allometric variation also seen in the prehistoric subspecies of Jaguars which were as big as Bengal Tigers? Would their bite force be stronger or weaker than the Tiger’s?
No jaguar skull has been found that is much larger than an extant jaguar so we cannot actually say.
(04-30-2022, 03:14 AM)LonePredator Wrote:
(04-30-2022, 03:09 AM)tigerluver Wrote:
(04-30-2022, 02:18 AM)LonePredator Wrote:
(04-30-2022, 02:10 AM)tigerluver Wrote:
(04-29-2022, 02:41 AM)LonePredator Wrote:
(04-29-2022, 02:33 AM)tigerluver Wrote:
(04-28-2022, 10:05 PM)LonePredator Wrote: @tigerluver How did they estimate the size of Smilodon Populator when it was so different from currently living felids? Like it’s morphology was entirely different from the living cats.
Can you tell me the equations which has been used for it and are all these allometric equations similar in different kinds of uses? For example, is an allometric equation to find the weight of smilodon populator similar to say Cave Bear? Can you tell me a little bit about this?
You make an excellent observation and truly, no publication has really been able to address the limitation.
The oldest estimates from Anyonge used circumferences of the long bones. Christiansen and Harris (2005) did similar but also added many other dimensions of the bone. Both used extant felids as the source of the regression equations and cannot actually account for the unique proportions of Smilodon. The hope is that circumference has minimal interspecific different in estimating body mass in these. While Campione et al. (2012) did show circumference is best correlated with body mass across taxa, the percent error is still actually quite significant. Another example of the problem of Smilodon is that it is front heavy, therefore there is a comparatively disproportionate amount of weight supported by the forelimbs as compared to hindlimbs (while in extant cats the distribution is more even). If we think about this theoretically, this would result in the humerus robusticity overestimating (a greater percentage of the body weight is stressing the forelimbs, so they will be proportionately thicker for the total weight) while femur robusticity (a lesser percentage of the body weight is stressing the hindlimbs, so they would be proportionately thinner for the body weight) would underestimate.
The allometric equations were based on felids. Separate equations have been made for bears. When we compare the estimates from the equations, the results are different. This means an allometric equation applied to a felid cannot really apply accurately to a bear.
The giant Smilodon skull was estimated using a regression developed from felid skulls. The issue here is that Smilodon had a smaller skull for its body as compared to extant felids. Therefore, this estimate is probably a significant underestimate.
So there is no perfect formula for Smilodon. Volumetric estimation can be attempted but it gets exposed to subjectivity as the model is essentially art subject to the artist's thoughts.
Thankyou very much. A very well detailed explanation. I will check out those sources. As far as I remember, I think that the oldest estimates which came from Anyonge were gross overestimations.
Just one more question, do you think that the isometric scaling of extant felids by scaling the the mass cubically in relation to scaling the length linearly give an accurate enough bodymass estimate? I’m aware it’s just a law of physics which only works on objects of similar proportions but...
What if I do the same for the shoulder height, chest girth and head body length. I linearly scale all these dimensions to the dimensions of the big Tiger and then cubically scale the mass and then average out all the three mass estimates then will it practically hold up?
Do you think that will give a good enough estimate of the mass of the big Tiger and can you roughly predict a percentage error that I could get in my result?
And once again, thanks a lot for your detailed explaination.
Isometry is the most parsimonious when are comparing animals of the same species so I prefer it.
Isometry works with 3 dimensions (length, width, height). Therefore, if you use three measurements that are surrogates for these dimensions, cubically scale the mass, then average them together, you should get an estimate that ideally accurately estimates the mass/volume. There is no real way to calculate percent error unfortunately.
Another way to do it is to multiple the difference ratio of length by the difference ratio of width and the difference ratio of height. This is based on the formula for volume (length * width * height). For instance, if a tiger is 1.2x longer, 1.1x width, and 1.4x taller than another tiger, you would do:
Mass bigger tiger = Mass smaller tiger * (1.2 * 1.1 * 1.4) = Mass smaller tiger * 2.002
This way is mathematically more accurate than averages the cubically scaled masses together.
This makes it much more simpler. Thanks a lot! I was calculating with all three dimensions separately and then averaging them out and even though it was working well, I’ll try this out now.
Just one more question. I’ve seen in some studies which show that the bite force of Jaguar is 3/4th that of a Bengal Tiger while the bodymass of the Jaguar is only half of the Tiger.
But can we really say that Jaguar has pound for pound stronger bite? Because when we scale the Jaguar to the same weight as the Tiger (by 2x) then the bite force would only increase by 1.777 times, right? Because the cross sectional area would only increase by an exponent of 2 while the mass increases by an exponent of 3.
And I calculated this and found that when mass of the Jaguar is scaled to 200kg from 100 then the force would still be about 12% weaker. Don’t you also think that the Jaguar would still have a weaker bite force than the Tiger if we scale a Jaguar by 2 times to make it equal in weight as the Tiger??
In the literal sense your math would be right. However, as skulls get bigger there are allometric effects such as increase in the length of the masseteric fossa which would increase the bite force.
Therefore, regressions are made to account for the allometric changes. Wroe et al. finds the jaguar's bite force is above the regression line:
*This image is copyright of its original author
The positioning of where the point is as compared to the regression line is measured by the bite force quotient (BFQ). In the study, the jaguar's BFQ is 1.37 and the tiger's 1.27. A weakness of the study is that actual weights of animals are not used, just estimates. Therefore, the BFQ may not be accurate.
A more fruitful measurement would probably be bite force over skull length. I ran the regression quickly (can't figure out how to label datapoints, if I have time later I will update the post):
*This image is copyright of its original author
Based on the second graph, the jaguar has significantly stronger bite than predicted for its skull length.
What about a Sumatran Tiger? Do you think a 120kg Sumatran Tiger’s bite force be higher or lower than a 120kg Jaguar assuming that the Sumatran’s morphology is the same as Bengals but they just have a bigger skull for their body (which I am assuming is the actual case as well since isometric equations with Bengals and Sumatrans as surrogates have been used to estimate Ngandong and the Borneo Tiger)
Intrinsically, if an animal has a bigger skull for its body, then its mass-based BFQ will be higher.
I ran a hypothetical with a smaller tiger skull, and while the gap between tiger and jaguar decreases, it's still large.
*This image is copyright of its original author
This is assuming the smaller tiger scales isometrically with the larger tiger. If it has a bigger head, than the skull length based BFQ would be higher. Note these graphs are bite force versus skull length, not weight.
So the actual definition of ‘pound for pound’ is quite subjective it seems. One can compare the two with the exact same morphologies they already possess while another can do it by keeping in mind the allometric variations which occur when the specimen gets larger and in this case when the Jaguar is upscaled to such a point then the morphology would change to such a point which no extant Jaguar actually possesses. This is what I don’t like about hypotheticals.
It also seems like this ‘pound for pound’ is quite vague and no certain claims can be made about ‘pound for pound’ comparisons.
(04-30-2022, 04:00 AM)tigerluver Wrote: No jaguar skull has been found that is much larger than an extant jaguar so we cannot actually say.
Now that you mention this, by chance do you have the document where this skull is described, or at least you know its size?
*This image is copyright of its original author
*This image is copyright of its original author
As far I know this is a giant jaguar from Talara, Peru, the one that was believed it was from Panthera atrox. I used the scale provided and I got a GSL of c.33 cm, but I don't know for sure.
(04-30-2022, 04:00 AM)tigerluver Wrote: No jaguar skull has been found that is much larger than an extant jaguar so we cannot actually say.
Now that you mention this, by chance do you have the document where this skull is described, or at least you know its size?
*This image is copyright of its original author
*This image is copyright of its original author
As far I know this is a giant jaguar from Talara, Peru, the one that was believed it was from Panthera atrox. I used the scale provided and I got a GSL of c.33 cm, but I don't know for sure.
I think the description is in a master's thesis by Seymour from 1983. Problem is, it's no where online. Maybe contacting Dr. Seymour could give us some luck.
04-30-2022, 08:25 AM( This post was last modified: 04-30-2022, 08:26 AM by LonePredator )
(04-30-2022, 03:09 AM)tigerluver Wrote:
(04-30-2022, 02:18 AM)LonePredator Wrote:
(04-30-2022, 02:10 AM)tigerluver Wrote:
(04-29-2022, 02:41 AM)LonePredator Wrote:
(04-29-2022, 02:33 AM)tigerluver Wrote:
(04-28-2022, 10:05 PM)LonePredator Wrote: @tigerluver How did they estimate the size of Smilodon Populator when it was so different from currently living felids? Like it’s morphology was entirely different from the living cats.
Can you tell me the equations which has been used for it and are all these allometric equations similar in different kinds of uses? For example, is an allometric equation to find the weight of smilodon populator similar to say Cave Bear? Can you tell me a little bit about this?
You make an excellent observation and truly, no publication has really been able to address the limitation.
The oldest estimates from Anyonge used circumferences of the long bones. Christiansen and Harris (2005) did similar but also added many other dimensions of the bone. Both used extant felids as the source of the regression equations and cannot actually account for the unique proportions of Smilodon. The hope is that circumference has minimal interspecific different in estimating body mass in these. While Campione et al. (2012) did show circumference is best correlated with body mass across taxa, the percent error is still actually quite significant. Another example of the problem of Smilodon is that it is front heavy, therefore there is a comparatively disproportionate amount of weight supported by the forelimbs as compared to hindlimbs (while in extant cats the distribution is more even). If we think about this theoretically, this would result in the humerus robusticity overestimating (a greater percentage of the body weight is stressing the forelimbs, so they will be proportionately thicker for the total weight) while femur robusticity (a lesser percentage of the body weight is stressing the hindlimbs, so they would be proportionately thinner for the body weight) would underestimate.
The allometric equations were based on felids. Separate equations have been made for bears. When we compare the estimates from the equations, the results are different. This means an allometric equation applied to a felid cannot really apply accurately to a bear.
The giant Smilodon skull was estimated using a regression developed from felid skulls. The issue here is that Smilodon had a smaller skull for its body as compared to extant felids. Therefore, this estimate is probably a significant underestimate.
So there is no perfect formula for Smilodon. Volumetric estimation can be attempted but it gets exposed to subjectivity as the model is essentially art subject to the artist's thoughts.
Thankyou very much. A very well detailed explanation. I will check out those sources. As far as I remember, I think that the oldest estimates which came from Anyonge were gross overestimations.
Just one more question, do you think that the isometric scaling of extant felids by scaling the the mass cubically in relation to scaling the length linearly give an accurate enough bodymass estimate? I’m aware it’s just a law of physics which only works on objects of similar proportions but...
What if I do the same for the shoulder height, chest girth and head body length. I linearly scale all these dimensions to the dimensions of the big Tiger and then cubically scale the mass and then average out all the three mass estimates then will it practically hold up?
Do you think that will give a good enough estimate of the mass of the big Tiger and can you roughly predict a percentage error that I could get in my result?
And once again, thanks a lot for your detailed explaination.
Isometry is the most parsimonious when are comparing animals of the same species so I prefer it.
Isometry works with 3 dimensions (length, width, height). Therefore, if you use three measurements that are surrogates for these dimensions, cubically scale the mass, then average them together, you should get an estimate that ideally accurately estimates the mass/volume. There is no real way to calculate percent error unfortunately.
Another way to do it is to multiple the difference ratio of length by the difference ratio of width and the difference ratio of height. This is based on the formula for volume (length * width * height). For instance, if a tiger is 1.2x longer, 1.1x width, and 1.4x taller than another tiger, you would do:
Mass bigger tiger = Mass smaller tiger * (1.2 * 1.1 * 1.4) = Mass smaller tiger * 2.002
This way is mathematically more accurate than averages the cubically scaled masses together.
This makes it much more simpler. Thanks a lot! I was calculating with all three dimensions separately and then averaging them out and even though it was working well, I’ll try this out now.
Just one more question. I’ve seen in some studies which show that the bite force of Jaguar is 3/4th that of a Bengal Tiger while the bodymass of the Jaguar is only half of the Tiger.
But can we really say that Jaguar has pound for pound stronger bite? Because when we scale the Jaguar to the same weight as the Tiger (by 2x) then the bite force would only increase by 1.777 times, right? Because the cross sectional area would only increase by an exponent of 2 while the mass increases by an exponent of 3.
And I calculated this and found that when mass of the Jaguar is scaled to 200kg from 100 then the force would still be about 12% weaker. Don’t you also think that the Jaguar would still have a weaker bite force than the Tiger if we scale a Jaguar by 2 times to make it equal in weight as the Tiger??
In the literal sense your math would be right. However, as skulls get bigger there are allometric effects such as increase in the length of the masseteric fossa which would increase the bite force.
Therefore, regressions are made to account for the allometric changes. Wroe et al. finds the jaguar's bite force is above the regression line:
*This image is copyright of its original author
The positioning of where the point is as compared to the regression line is measured by the bite force quotient (BFQ). In the study, the jaguar's BFQ is 1.37 and the tiger's 1.27. A weakness of the study is that actual weights of animals are not used, just estimates. Therefore, the BFQ may not be accurate.
A more fruitful measurement would probably be bite force over skull length. I ran the regression quickly (can't figure out how to label datapoints, if I have time later I will update the post):
*This image is copyright of its original author
Based on the second graph, the jaguar has significantly stronger bite than predicted for its skull length.
Do you happen to have a table for the regression graph of logarithm of bite force against the log of bodymass? It’s hard to get the log cb to log bm ratio just from the graph so could you share a regression table of it if you have it?
(04-28-2022, 10:05 PM)LonePredator Wrote: @tigerluver How did they estimate the size of Smilodon Populator when it was so different from currently living felids? Like it’s morphology was entirely different from the living cats.
Can you tell me the equations which has been used for it and are all these allometric equations similar in different kinds of uses? For example, is an allometric equation to find the weight of smilodon populator similar to say Cave Bear? Can you tell me a little bit about this?
You make an excellent observation and truly, no publication has really been able to address the limitation.
The oldest estimates from Anyonge used circumferences of the long bones. Christiansen and Harris (2005) did similar but also added many other dimensions of the bone. Both used extant felids as the source of the regression equations and cannot actually account for the unique proportions of Smilodon. The hope is that circumference has minimal interspecific different in estimating body mass in these. While Campione et al. (2012) did show circumference is best correlated with body mass across taxa, the percent error is still actually quite significant. Another example of the problem of Smilodon is that it is front heavy, therefore there is a comparatively disproportionate amount of weight supported by the forelimbs as compared to hindlimbs (while in extant cats the distribution is more even). If we think about this theoretically, this would result in the humerus robusticity overestimating (a greater percentage of the body weight is stressing the forelimbs, so they will be proportionately thicker for the total weight) while femur robusticity (a lesser percentage of the body weight is stressing the hindlimbs, so they would be proportionately thinner for the body weight) would underestimate.
The allometric equations were based on felids. Separate equations have been made for bears. When we compare the estimates from the equations, the results are different. This means an allometric equation applied to a felid cannot really apply accurately to a bear.
The giant Smilodon skull was estimated using a regression developed from felid skulls. The issue here is that Smilodon had a smaller skull for its body as compared to extant felids. Therefore, this estimate is probably a significant underestimate.
So there is no perfect formula for Smilodon. Volumetric estimation can be attempted but it gets exposed to subjectivity as the model is essentially art subject to the artist's thoughts.
Thankyou very much. A very well detailed explanation. I will check out those sources. As far as I remember, I think that the oldest estimates which came from Anyonge were gross overestimations.
Just one more question, do you think that the isometric scaling of extant felids by scaling the the mass cubically in relation to scaling the length linearly give an accurate enough bodymass estimate? I’m aware it’s just a law of physics which only works on objects of similar proportions but...
What if I do the same for the shoulder height, chest girth and head body length. I linearly scale all these dimensions to the dimensions of the big Tiger and then cubically scale the mass and then average out all the three mass estimates then will it practically hold up?
Do you think that will give a good enough estimate of the mass of the big Tiger and can you roughly predict a percentage error that I could get in my result?
And once again, thanks a lot for your detailed explaination.
Isometry is the most parsimonious when are comparing animals of the same species so I prefer it.
Isometry works with 3 dimensions (length, width, height). Therefore, if you use three measurements that are surrogates for these dimensions, cubically scale the mass, then average them together, you should get an estimate that ideally accurately estimates the mass/volume. There is no real way to calculate percent error unfortunately.
Another way to do it is to multiple the difference ratio of length by the difference ratio of width and the difference ratio of height. This is based on the formula for volume (length * width * height). For instance, if a tiger is 1.2x longer, 1.1x width, and 1.4x taller than another tiger, you would do:
Mass bigger tiger = Mass smaller tiger * (1.2 * 1.1 * 1.4) = Mass smaller tiger * 2.002
This way is mathematically more accurate than averages the cubically scaled masses together.
This makes it much more simpler. Thanks a lot! I was calculating with all three dimensions separately and then averaging them out and even though it was working well, I’ll try this out now.
Just one more question. I’ve seen in some studies which show that the bite force of Jaguar is 3/4th that of a Bengal Tiger while the bodymass of the Jaguar is only half of the Tiger.
But can we really say that Jaguar has pound for pound stronger bite? Because when we scale the Jaguar to the same weight as the Tiger (by 2x) then the bite force would only increase by 1.777 times, right? Because the cross sectional area would only increase by an exponent of 2 while the mass increases by an exponent of 3.
And I calculated this and found that when mass of the Jaguar is scaled to 200kg from 100 then the force would still be about 12% weaker. Don’t you also think that the Jaguar would still have a weaker bite force than the Tiger if we scale a Jaguar by 2 times to make it equal in weight as the Tiger??
In the literal sense your math would be right. However, as skulls get bigger there are allometric effects such as increase in the length of the masseteric fossa which would increase the bite force.
Therefore, regressions are made to account for the allometric changes. Wroe et al. finds the jaguar's bite force is above the regression line:
*This image is copyright of its original author
The positioning of where the point is as compared to the regression line is measured by the bite force quotient (BFQ). In the study, the jaguar's BFQ is 1.37 and the tiger's 1.27. A weakness of the study is that actual weights of animals are not used, just estimates. Therefore, the BFQ may not be accurate.
A more fruitful measurement would probably be bite force over skull length. I ran the regression quickly (can't figure out how to label datapoints, if I have time later I will update the post):
*This image is copyright of its original author
Based on the second graph, the jaguar has significantly stronger bite than predicted for its skull length.
Do you happen to have a table for the regression graph of logarithm of bite force against the log of bodymass? It’s hard to get the log cb to log bm ratio just from the graph so could you share a regression table of it if you have it?
05-04-2022, 11:04 AM( This post was last modified: 05-04-2022, 11:05 AM by jrocks )
(04-30-2022, 08:58 AM)tigerluver Wrote:
(04-30-2022, 08:25 AM)LonePredator Wrote:
(04-30-2022, 03:09 AM)tigerluver Wrote:
(04-30-2022, 02:18 AM)LonePredator Wrote:
(04-30-2022, 02:10 AM)tigerluver Wrote:
(04-29-2022, 02:41 AM)LonePredator Wrote:
(04-29-2022, 02:33 AM)tigerluver Wrote:
(04-28-2022, 10:05 PM)LonePredator Wrote: @tigerluver How did they estimate the size of Smilodon Populator when it was so different from currently living felids? Like it’s morphology was entirely different from the living cats.
Can you tell me the equations which has been used for it and are all these allometric equations similar in different kinds of uses? For example, is an allometric equation to find the weight of smilodon populator similar to say Cave Bear? Can you tell me a little bit about this?
You make an excellent observation and truly, no publication has really been able to address the limitation.
The oldest estimates from Anyonge used circumferences of the long bones. Christiansen and Harris (2005) did similar but also added many other dimensions of the bone. Both used extant felids as the source of the regression equations and cannot actually account for the unique proportions of Smilodon. The hope is that circumference has minimal interspecific different in estimating body mass in these. While Campione et al. (2012) did show circumference is best correlated with body mass across taxa, the percent error is still actually quite significant. Another example of the problem of Smilodon is that it is front heavy, therefore there is a comparatively disproportionate amount of weight supported by the forelimbs as compared to hindlimbs (while in extant cats the distribution is more even). If we think about this theoretically, this would result in the humerus robusticity overestimating (a greater percentage of the body weight is stressing the forelimbs, so they will be proportionately thicker for the total weight) while femur robusticity (a lesser percentage of the body weight is stressing the hindlimbs, so they would be proportionately thinner for the body weight) would underestimate.
The allometric equations were based on felids. Separate equations have been made for bears. When we compare the estimates from the equations, the results are different. This means an allometric equation applied to a felid cannot really apply accurately to a bear.
The giant Smilodon skull was estimated using a regression developed from felid skulls. The issue here is that Smilodon had a smaller skull for its body as compared to extant felids. Therefore, this estimate is probably a significant underestimate.
So there is no perfect formula for Smilodon. Volumetric estimation can be attempted but it gets exposed to subjectivity as the model is essentially art subject to the artist's thoughts.
Thankyou very much. A very well detailed explanation. I will check out those sources. As far as I remember, I think that the oldest estimates which came from Anyonge were gross overestimations.
Just one more question, do you think that the isometric scaling of extant felids by scaling the the mass cubically in relation to scaling the length linearly give an accurate enough bodymass estimate? I’m aware it’s just a law of physics which only works on objects of similar proportions but...
What if I do the same for the shoulder height, chest girth and head body length. I linearly scale all these dimensions to the dimensions of the big Tiger and then cubically scale the mass and then average out all the three mass estimates then will it practically hold up?
Do you think that will give a good enough estimate of the mass of the big Tiger and can you roughly predict a percentage error that I could get in my result?
And once again, thanks a lot for your detailed explaination.
Isometry is the most parsimonious when are comparing animals of the same species so I prefer it.
Isometry works with 3 dimensions (length, width, height). Therefore, if you use three measurements that are surrogates for these dimensions, cubically scale the mass, then average them together, you should get an estimate that ideally accurately estimates the mass/volume. There is no real way to calculate percent error unfortunately.
Another way to do it is to multiple the difference ratio of length by the difference ratio of width and the difference ratio of height. This is based on the formula for volume (length * width * height). For instance, if a tiger is 1.2x longer, 1.1x width, and 1.4x taller than another tiger, you would do:
Mass bigger tiger = Mass smaller tiger * (1.2 * 1.1 * 1.4) = Mass smaller tiger * 2.002
This way is mathematically more accurate than averages the cubically scaled masses together.
This makes it much more simpler. Thanks a lot! I was calculating with all three dimensions separately and then averaging them out and even though it was working well, I’ll try this out now.
Just one more question. I’ve seen in some studies which show that the bite force of Jaguar is 3/4th that of a Bengal Tiger while the bodymass of the Jaguar is only half of the Tiger.
But can we really say that Jaguar has pound for pound stronger bite? Because when we scale the Jaguar to the same weight as the Tiger (by 2x) then the bite force would only increase by 1.777 times, right? Because the cross sectional area would only increase by an exponent of 2 while the mass increases by an exponent of 3.
And I calculated this and found that when mass of the Jaguar is scaled to 200kg from 100 then the force would still be about 12% weaker. Don’t you also think that the Jaguar would still have a weaker bite force than the Tiger if we scale a Jaguar by 2 times to make it equal in weight as the Tiger??
In the literal sense your math would be right. However, as skulls get bigger there are allometric effects such as increase in the length of the masseteric fossa which would increase the bite force.
Therefore, regressions are made to account for the allometric changes. Wroe et al. finds the jaguar's bite force is above the regression line:
*This image is copyright of its original author
The positioning of where the point is as compared to the regression line is measured by the bite force quotient (BFQ). In the study, the jaguar's BFQ is 1.37 and the tiger's 1.27. A weakness of the study is that actual weights of animals are not used, just estimates. Therefore, the BFQ may not be accurate.
A more fruitful measurement would probably be bite force over skull length. I ran the regression quickly (can't figure out how to label datapoints, if I have time later I will update the post):
*This image is copyright of its original author
Based on the second graph, the jaguar has significantly stronger bite than predicted for its skull length.
Do you happen to have a table for the regression graph of logarithm of bite force against the log of bodymass? It’s hard to get the log cb to log bm ratio just from the graph so could you share a regression table of it if you have it?
so are these weights right for the largest specimens of each prehistoric cat
smilodon populator 16.07 inch skull at around 490 kg if isometric scaling is used to scale up the 15.4 inch skull specimen to the 16.07 inch one
american lion 18.4 inch skull at 375 kg
natadomeri lion 19.08 inch skull at 390 kg
ngandong tiger 480 mm femur at 368 kg, i think i saw somewhere that there was a huge mandible found of a bornean tiger is it known much does that specimen is
also how did m. giganteus compare to these cats as i cant find much on them
05-04-2022, 06:15 PM( This post was last modified: 05-04-2022, 06:16 PM by LonePredator )
(05-04-2022, 11:04 AM)jrocks Wrote:
(04-30-2022, 08:58 AM)tigerluver Wrote:
(04-30-2022, 08:25 AM)LonePredator Wrote:
(04-30-2022, 03:09 AM)tigerluver Wrote:
(04-30-2022, 02:18 AM)LonePredator Wrote:
(04-30-2022, 02:10 AM)tigerluver Wrote:
(04-29-2022, 02:41 AM)LonePredator Wrote:
(04-29-2022, 02:33 AM)tigerluver Wrote:
(04-28-2022, 10:05 PM)LonePredator Wrote: @tigerluver How did they estimate the size of Smilodon Populator when it was so different from currently living felids? Like it’s morphology was entirely different from the living cats.
Can you tell me the equations which has been used for it and are all these allometric equations similar in different kinds of uses? For example, is an allometric equation to find the weight of smilodon populator similar to say Cave Bear? Can you tell me a little bit about this?
You make an excellent observation and truly, no publication has really been able to address the limitation.
The oldest estimates from Anyonge used circumferences of the long bones. Christiansen and Harris (2005) did similar but also added many other dimensions of the bone. Both used extant felids as the source of the regression equations and cannot actually account for the unique proportions of Smilodon. The hope is that circumference has minimal interspecific different in estimating body mass in these. While Campione et al. (2012) did show circumference is best correlated with body mass across taxa, the percent error is still actually quite significant. Another example of the problem of Smilodon is that it is front heavy, therefore there is a comparatively disproportionate amount of weight supported by the forelimbs as compared to hindlimbs (while in extant cats the distribution is more even). If we think about this theoretically, this would result in the humerus robusticity overestimating (a greater percentage of the body weight is stressing the forelimbs, so they will be proportionately thicker for the total weight) while femur robusticity (a lesser percentage of the body weight is stressing the hindlimbs, so they would be proportionately thinner for the body weight) would underestimate.
The allometric equations were based on felids. Separate equations have been made for bears. When we compare the estimates from the equations, the results are different. This means an allometric equation applied to a felid cannot really apply accurately to a bear.
The giant Smilodon skull was estimated using a regression developed from felid skulls. The issue here is that Smilodon had a smaller skull for its body as compared to extant felids. Therefore, this estimate is probably a significant underestimate.
So there is no perfect formula for Smilodon. Volumetric estimation can be attempted but it gets exposed to subjectivity as the model is essentially art subject to the artist's thoughts.
Thankyou very much. A very well detailed explanation. I will check out those sources. As far as I remember, I think that the oldest estimates which came from Anyonge were gross overestimations.
Just one more question, do you think that the isometric scaling of extant felids by scaling the the mass cubically in relation to scaling the length linearly give an accurate enough bodymass estimate? I’m aware it’s just a law of physics which only works on objects of similar proportions but...
What if I do the same for the shoulder height, chest girth and head body length. I linearly scale all these dimensions to the dimensions of the big Tiger and then cubically scale the mass and then average out all the three mass estimates then will it practically hold up?
Do you think that will give a good enough estimate of the mass of the big Tiger and can you roughly predict a percentage error that I could get in my result?
And once again, thanks a lot for your detailed explaination.
Isometry is the most parsimonious when are comparing animals of the same species so I prefer it.
Isometry works with 3 dimensions (length, width, height). Therefore, if you use three measurements that are surrogates for these dimensions, cubically scale the mass, then average them together, you should get an estimate that ideally accurately estimates the mass/volume. There is no real way to calculate percent error unfortunately.
Another way to do it is to multiple the difference ratio of length by the difference ratio of width and the difference ratio of height. This is based on the formula for volume (length * width * height). For instance, if a tiger is 1.2x longer, 1.1x width, and 1.4x taller than another tiger, you would do:
Mass bigger tiger = Mass smaller tiger * (1.2 * 1.1 * 1.4) = Mass smaller tiger * 2.002
This way is mathematically more accurate than averages the cubically scaled masses together.
This makes it much more simpler. Thanks a lot! I was calculating with all three dimensions separately and then averaging them out and even though it was working well, I’ll try this out now.
Just one more question. I’ve seen in some studies which show that the bite force of Jaguar is 3/4th that of a Bengal Tiger while the bodymass of the Jaguar is only half of the Tiger.
But can we really say that Jaguar has pound for pound stronger bite? Because when we scale the Jaguar to the same weight as the Tiger (by 2x) then the bite force would only increase by 1.777 times, right? Because the cross sectional area would only increase by an exponent of 2 while the mass increases by an exponent of 3.
And I calculated this and found that when mass of the Jaguar is scaled to 200kg from 100 then the force would still be about 12% weaker. Don’t you also think that the Jaguar would still have a weaker bite force than the Tiger if we scale a Jaguar by 2 times to make it equal in weight as the Tiger??
In the literal sense your math would be right. However, as skulls get bigger there are allometric effects such as increase in the length of the masseteric fossa which would increase the bite force.
Therefore, regressions are made to account for the allometric changes. Wroe et al. finds the jaguar's bite force is above the regression line:
*This image is copyright of its original author
The positioning of where the point is as compared to the regression line is measured by the bite force quotient (BFQ). In the study, the jaguar's BFQ is 1.37 and the tiger's 1.27. A weakness of the study is that actual weights of animals are not used, just estimates. Therefore, the BFQ may not be accurate.
A more fruitful measurement would probably be bite force over skull length. I ran the regression quickly (can't figure out how to label datapoints, if I have time later I will update the post):
*This image is copyright of its original author
Based on the second graph, the jaguar has significantly stronger bite than predicted for its skull length.
Do you happen to have a table for the regression graph of logarithm of bite force against the log of bodymass? It’s hard to get the log cb to log bm ratio just from the graph so could you share a regression table of it if you have it?
so are these weights right for the largest specimens of each prehistoric cat
smilodon populator 16.07 inch skull at around 490 kg if isometric scaling is used to scale up the 15.4 inch skull specimen to the 16.07 inch one
american lion 18.4 inch skull at 375 kg
natadomeri lion 19.08 inch skull at 390 kg
ngandong tiger 480 mm femur at 368 kg, i think i saw somewhere that there was a huge mandible found of a bornean tiger is it known much does that specimen is
also how did m. giganteus compare to these cats as i cant find much on them
Not much was found of the Bornean Tiger but based on it there was an isometric size estimate with extant Tigers as surrogates and it suggests that this Tiger could have been extremely large. See the peer reviewed paper (Sherani, 2019). The weight was estimated at ~480kg but since not much was available, the estimate is likely to have high deviation from the actual weight.
The weight was estimated at 480kg but with a ±60kg deviation so 420-540kg according to the the paper below. Check it out.[/color]
(05-04-2022, 11:04 AM)jrocks Wrote: so are these weights right for the largest specimens of each prehistoric cat
smilodon populator 16.07 inch skull at around 490 kg if isometric scaling is used to scale up the 15.4 inch skull specimen to the 16.07 inch one
american lion 18.4 inch skull at 375 kg
natadomeri lion 19.08 inch skull at 390 kg
ngandong tiger 480 mm femur at 368 kg, i think i saw somewhere that there was a huge mandible found of a bornean tiger is it known much does that specimen is
also how did m. giganteus compare to these cats as i cant find much on them
I don't think that Smilodon populator weighed more than 450 kg even in a extream case, not even for the biggest skull of 408.4 mm in GSL.
The skull LACMHC 2900-3 for Panthera atrox is the second biggest from the sample known with a CBL of 410.4 mm and its weight is calculated at 351 kg, so the bigger one Univ.Calif.14001 with a CBL of 424.3 mm, which is marginally larger, probably was around 360 kg.
The Natodameri lion skull had a basal length of 380 mm which is smaller than the biggest Panthera atrox skulls, which suggest a lesser body mass, and I estimate that could be about 340 kg.
The Ngandong tiger was estimated at 368 kg by me, but an unpublished information from Dr Per Christiansen suggest a body mass of 380 kg.
Amont its genus, Amphimachairodus giganteus was big, but not extraordinary, with a shoulder height of up to 110 cm which match those from modern lions and tigres (remember that this genus had relative longer legs), with a biggest skull with a basal length of 315 mm (Turner & Anton, 1997), and a GSL of up to 363 mm (Sotnikova, 1992), it is in the range of the modern great cats, so probably a mass of 260-270 kg will be ok.
Maybe these figures are not as impresive as the ones proposed in the internet, but we must take in count that modern lions and tigers had average weights between 190 - 200 kg and those specimens are already big by any standard.
(05-04-2022, 11:04 AM)jrocks Wrote: so are these weights right for the largest specimens of each prehistoric cat
smilodon populator 16.07 inch skull at around 490 kg if isometric scaling is used to scale up the 15.4 inch skull specimen to the 16.07 inch one
american lion 18.4 inch skull at 375 kg
natadomeri lion 19.08 inch skull at 390 kg
ngandong tiger 480 mm femur at 368 kg, i think i saw somewhere that there was a huge mandible found of a bornean tiger is it known much does that specimen is
also how did m. giganteus compare to these cats as i cant find much on them
I don't think that Smilodon populator weighed more than 450 kg even in a extream case, not even for the biggest skull of 408.4 mm in GSL.
The skull LACMHC 2900-3 for Panthera atrox is the second biggest from the sample known with a CBL of 410.4 mm and its weight is calculated at 351 kg, so the bigger one Univ.Calif.14001 with a CBL of 424.3 mm, which is marginally larger, probably was around 360 kg.
The Natodameri lion skull had a basal length of 380 mm which is smaller than the biggest Panthera atrox skulls, which suggest a lesser body mass, and I estimate that could be about 340 kg.
The Ngandong tiger was estimated at 368 kg by me, but an unpublished information from Dr Per Christiansen suggest a body mass of 380 kg.
Amont its genus, Amphimachairodus giganteus was big, but not extraordinary, with a shoulder height of up to 110 cm which match those from modern lions and tigres (remember that this genus had relative longer legs), with a biggest skull with a basal length of 315 mm (Turner & Anton, 1997), and a GSL of up to 363 mm (Sotnikova, 1992), it is in the range of the modern great cats, so probably a mass of 260-270 kg will be ok.
Maybe these figures are not as impresive as the ones proposed in the internet, but we must take in count that modern lions and tigers had average weights between 190 - 200 kg and those specimens are already big by any standard.
oh wow, the basal length of the chateau natadomeri lion skull despite being 484.7 mm on total length was quite a lot less at 380 mm i never knew that
05-05-2022, 03:48 AM( This post was last modified: 05-05-2022, 03:49 AM by GuateGojira )
(05-05-2022, 02:21 AM)jrocks Wrote: oh wow, the basal length of the chateau natadomeri lion skull despite being 484.7 mm on total length was quite a lot less at 380 mm i never knew that
I see that there is a confusion here, the Natodameri lion is from Kenya and its ID is KNM-ND 59673 and for the moment is clasified as a modern lion Panthera leo. The Chateau "lion" came from France and its ID is CHA.1.98.C.3-246 and belong to the species Panthera spelaea fossilis.
So these are two different animals, from different species.
Now, if we focus specifically in the specimen CHA.1.98.C.3-246 from France, check that its skull is less than 2 cm bigger in the GSL than the biggest specimen of Panthera atrox (484.7 mm vs. 467.5 mm). In this case the estimated weight for an animal of that size was probably around 380 kg, but we nee to take in count that we don't know the body variations, for example, I remember that @tigerluver once told me (if I remember correctly) that Panthera spelaea had bigger skulls in relation to its body than Panthera atrox, and if that is the case, the 2 cm in difference will be irrelevant and both specimens could weight around the same.
As in the end the goal of these estimations is comparison, here is a comparative look:
Wheeler and Jefferson (2009) tentatively associate 458 mm femur with the 458 mm P. atrox skull. This is a 1:1 GSL:FL ratio. By extension, the 467.5 mm skull has a 467.5 mm femur.
The very large Sabol P. spelaea has a GSL of 437 mm with an average FL of 433 mm, a ratio of 0.99 which shows a rather huge skull for any known cat. By extension, the Chateau skull of 484.5 mm has a FL of 480 mm.
The estimated basal length of the Natodomeri skull hints at a GSL of around 445 mm-450 mm (CBL about 400 mm). If this specimen maintains extant male P. leo proportions then we can use the Mazak et al. (2011) data to extrapolate a FL of 460 mm-470 mm. If it has cave lion-esque proportions then the FL would be a bit less.
The largest Late Pleistocene P. spelaea femur is 470 mm in FL.
The Ngandong tiger femur is 480 mm in FL. Tigers have a bit more volume/weight to femur length due to having a longer torso as compared to femur length (see Christiansen and Adolfssen 2007 and how tigers are longer for their shoulder height).
05-05-2022, 11:52 PM( This post was last modified: 05-05-2022, 11:55 PM by GuateGojira )
(05-05-2022, 03:48 AM)GuateGojira Wrote: The Chateau "lion" came from France and its ID is CHA.1.98.C.3-246 and belong to the species Panthera spelaea fossilis.
Speaking about this specimen, I tried several times to search a picture of it, or at least any other reference about it, but failed until now.....
In the paper "The big cats of the fossil site Château Breccia Northern Section (Saône-et-Loire, Burgundy, France): stratigraphy, palaeoenvironment, ethology and biochronological dating" from Argant and team (2007) I found a small mention about this specimen, check it:
*This image is copyright of its original author
Based in it, it seems that there are other bones related, which is great as we could have a better idea of the proportions of this specimen and this species overall.
I found a comparison in the web, check it:
*This image is copyright of its original author
Interesesting altough exagerated in both size and weight, what called my attention is the image of the supposed skull of the Chateau specimen, this one:
*This image is copyright of its original author
I don't know if that is the real skull, but that amorphous image do not look like the description made by Argant, although been honest they do not mention if the skull, even been complete, was crushed.
If anyone have more information about this specimen, it will be great if you can share it.
Wooooow! Great information man, thank you for sharing.
Now, if I am not mistaken, this table is about all the bones of the specimen asociated, correct?
*This image is copyright of its original author
If that is correct, the bones are not exceptional at all, in fact, they are average for Panthera atrox and just slightly longer than the biggest modern tigers. And checking the skull, it is so crushed that it could be possible that its sceptional length could be just an efect of that?
*This image is copyright of its original author
So, this is the skull CHA.1‑98‑C3‑246 of 483.6 mm, is very flat and deformed, but please tell me your appreciation.
05-06-2022, 04:04 AM( This post was last modified: 05-06-2022, 04:12 AM by tigerluver )
I think I will need to post in two parts. One for the skull itself then one on investigating the associations.
For the skull, here is a comparison with two other Middle Pleistocene lions per Marciszak et al. (2014), P. spelaea (Sabol 2018), and P. atrox (Merriam and Stock 1932):
*This image is copyright of its original author
From top to bottom: P. atrox (458 mm), P. spelaea (437 mm), Chateau (484 mm), Mauer (442 mm), Petralona (416 mm)
Now from visual assessment, either Chateau is presenting a very weasel-like, low, and long skull that shows some extreme uniqueness in P. fossilis, or the taphonomic distortion due to crushing is immense.
*This image is copyright of its original author
Note the following:
1. The relative position of the prosthion to the condyles. In all lions, the condyles are higher. In Chateau, the condyles are lower.
2. The ventral margin of the snout shows where the skull is clearly crushed. One can follow the dashed line to see the break's boundary. Now here is a figure that is attempting to put the two halves back together in a more anatomically natural position (outlined white is the old area and position of the skull):
*This image is copyright of its original author
Note this fixes the relative positions of the prosthion and condyles:
*This image is copyright of its original author
This morphology better matches with the other Middle Pleistocene lions and therefore I feel that the low set nature of the skull as it is presented is due to taphonomic distortion/crushing and not actually representative of a unique morphology. Had the other two Middle Pleistocene lion skulls not been available, I would not be as convinced.
With that, the 484 mm value is seemingly then not the true length of the skull. From the 2D image comparison it appears the GSL measurements shrinks by about 5%. Then we have to factor in the crushing force lengthening the skull as a whole. This probably reduces the true GSL to around 460 mm. Still giant of course, but in the ranks of P. atrox and P. spelaea.
