Freak Felids - A Discussion of History's Largest Felines

[tigerluver]

On tiger lengths, the 388 kg specimen was not used in the length estimate in the final table. By greatest length, I was referring to the 305-315 cm tigers that were around 300-320 kg. Regardless, I concluded a while back that long bones aren't that well correlated with total length, and one can't be certain of the bone robusticities of those specimens, so reconstruction estimates were discarded. Pleistocene cats differ a bit too much.

I see you have looked through the old discussions on yuku. The old equations are outdated at this point, including the early ones here. For lions, at the time, I only had the three poorly correlated datapoints of Christiansen and Harris. Same for tigers. Using tigers with lions does put some false allometry (overestimate lions, underestimate tigers) if you are strictly applying the equation to only tigers or only lions. The same false negative allometry occurs when you use jaguars with lions when applying it to a certained species (overestimate jagaurs, underestimate lions). Cave lions were given the benefit of the doubt in their proportion, and a midway was assumed. All the equations I use now are slightly different and also log scaled (power approach causing asymptotic issues), thanks to the newer database, so smaller species don't have to be relied on (as they can cause strong issues with allometry, as Anyonge and Christiansen showed). The outlier was removed after email contact with a staff at the museum regarding the specimen's health at death, when it was weighed. The 220 kg tiger is actually 230 kg, confirmed by future works of Christiansen and another author (Campione, 2012) who posted a huge database on animal femurs and humerus. I can attach that file here if people would be interested. Other than that, not much to be discussed, no point in going over what's outdated and weaker in power. Points I did not address about the equation were already addressed, I had the same doubts you did and fixed them. Not every post's equations and estimates have been updated here. The equations at the start of the thread were copied from yuku and not altered. Once things get locked into publishing, I can't update equations anyhow for obvious copyright reasons. This thread and old threads are a timeline of the evolution of our understanding of paleobiology, with like science, recent posts applying changes to previous status quo.

Day and Jane's equation was based on the animal in the flesh, so all that you have brought up had been accounted for. What basis did you use your body length estimation, as based on published data, 2500 mm is a bit of an overestimate. Here I could slide in a "bias" accusation as you did again a few times, but I'd rather leave space for explanation. Lastly, the point goes back to the high variability of MT proportions. If long bones are not a great predictor of body length, MTs and MCs are even worse, being one possible explanation to why published data does not match your estimate.

What build would you say cave lions were? Tigers are proportionately heavier than lions. I used long bone ratios (they reflect proportional weight) and late cave lions match lions exactly, i's here on this thread, but I haven't given the new regression estimates, which result in a bit lower masses, with lions only due to the doubts. In the latest posts, I kept it to isometry off lions for simplicity.

Another note, bones closer to the body (femur, humerus) scale more positively allometrically in terms of length than bones further away (ulna, tibia, etc.). Closer bones are more incorporated in the core body, and maybe that explains correlations. Lower bones could simply elongate for cursoriality purposes and not robusicity purposes in the taller species, explaining the negative allometry. Turner's table might support this. Epiphysis diameters also scaled quite negatively while shaft diameters positively.

On articular and greatest length. Christiansen's humerus length actually included the entirety of the femur, under the assumption that the protruding spur of the distal humerus is articular as most definitions says, test from his images yourself. Femur, tibia, etc. articular and greatest lengths are also the same, the articular surfaces are at the official ends of such bones. Ulna length had to be differentiated due to the nature of the bone itself, as you know, and is why Christiansen took the time to go over the ulna. All in all, his lengths are greatest lengths, refer to Christiansen 1999b for the assertion from the man himself.

On the tiger's femur bone itself. I also recognize the distortion possibility. The bone is straightened in the manner vK measured it, the condyles are even. All the doubts you have stated are reasonable, I've had the same ones before I posted anything. So here's how I tried to address them. I tested distortion out by measuring myself other pictures in vK's book with measurements he published, and everything matched very well with ratios being equal to the hundredths place , thus distortion did not look to be there. The femoral thinning above midshaft from this view is actually seen in some tigers, such as the Trinil femur. Albeit, this is not considered the point of least circumference as the posterior side is actually more robust there. A greatest LM width of 94 mm for a femur of 480 mm would require the lengthening the femur vK's photo shows to an irrational amount. Plus, as long as the item is in the center of the frame the distortion is left out to the far sides of the frame. Christiansen used photos to measure as well with likely the same methods, so that would balance that out as well. Albeit, my measurements are measured by hand, but I don't think this would be a problem as I've just described. Next, vK actually differentiated between diameter and greatest width in his book from proximal/distal. Furthermore, I went into Dawkins to extrapolate vK's measurements. They were at odd places, and not the greatest width whatsoever. Actually Dawkin's himself measured cave lion bones awkwardly too, where proximal and distal diameters were smaller than they would have been if it was DAW, making it look like they were thinner than modern species. For example, a 422 mm femur had LM proximal width of 76.2 mm. Such a value cannot be of greatest proximal width on a lion bone of that length, something around the 100 mm is more realistic. vK seems to have followed suit. Next, Christiansen's DAW scales to equally the distal frontal breadth as long as there's no spurs and frontal plane widening as some femurs have, especially in cats due to the nature of the curvature. You can test it on pictoral femurs such as in Brongersma or yourself or on any femur of any species without a spur or frontal widening (occurs in some species like humans).

Supplemental picture straight from Brogersma, as the wording may not have explained everything clearly:

*This image is copyright of its original author

On the proximal widths of the tiger femur. A LM proximal width of 94 mm cannot have a AP diameter of 59 mm in any cat or bear, it's impossible. Proximal AP/LM is in the low .40s for bears and high .40s for all cats, including P. atrox. The ratio itself is wrong and one must remember tigers have thin bones compared to the rest of Panthera, in both the LM and AP angles. 59 mm to the 110 mm shown in the picture is at the high end of cat range, makes more sense. The distal diameter vK gave of 88 mm cannot be DAW either, as explained by the notch width he also wrote on. Lastly, the proximal, distal, and midshaft widths are very similar to that of the modern Javan tiger. 

On that note, if I did not address something, please let me know. I spend a good hour plus writing this and your posts are mighty long (not a bad thing by any means), and it makes it easy to miss words. Also, we have continuously answered your questions, if you could please respond to our's as well. Especially, what is your mathematical model, as based on your Crater example, it seems more prone to interpretation than regression. Again, there is no way giving this general information can hurt, especially, as it looks to be, there is no expectations of getting anything published. You must admit, a large portion of the data you have found, as in the case of all of our members here, has come from this community. Collectively, posters have put the entirety of sources together and have all corners covered.

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