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Pleistocene Big Cats
Freak Felids - A Discussion of History's Largest Felines
Freak Felids - A Discussion of History's Largest Felines
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Freak Felids - A Discussion of History's Largest Felines
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I guess the giant cheetah must have proportionally a smaller skull, that's why it is prone to the underestimation.
Since in the modern paleontologist community might tend to mostly focus on the cranial measurement, while overlook the rests. 
I agree 100%, Van Valkenburg dental formulas give underestimations and the skull ones give overestimations.
Other issue is the differences between species. We know that lions have longer molars than tigers, so with those formulas, they would produce "heavier" lions without taking in count those differences. From my personal experience, I guess that the formulas of Legendre and Roth (1988) are better, at least they have give me reliable weights, for tigers at least. Normally scientists use skull and dental measurements because they are the most common fossils, but the problem is the real correlation between these bones and the actual body mass of the animals. Weight is a tricky business. 
Agreed @GuateGojira.
The number 1 issue is that these formulas are made with a bit of a fallacy. They use published means of weights but then use the mean of the 10 or so specimens the authors measure themselves. Most authors still use this method, except for Christiansen. When you use y-values that didn't belong to the x-values, overestimation and underestimation is going to happen. Another issue is that random chance within the small sample size can give a scale factor which underestimates or overestimates the specimen inaccurately. Isometry may be the safe bet in my head sometimes, as we're using a law to predict mass rather than scale factors that could have been skewed by random chance of the sample. I think I'll take a look at old jaguars to see if they were supersized as well, will post back soon. Dr. Marciszak has the crania of those specimens covered very well too. From here, I'll just use isometry to give mass values.  *This image is copyright of its original author I made an equation which predicts condylobasal length from m1 and p4 measurements using jaguar skulls mentioned in Merriam and Stock (1932). I found that the p3 had essentially no correlation to skull size, while the m1 had a moderate correlation. Thus, for m1, I used equation values for CBL reconstruction, but for the p3 I used an average ratio. From the m1 reconstructions, the largest CBLs for P. toscana and P. gombazoegensis of Bisnik were ~300 mm. The largest P. gombazoegensis CBL was 325 mm. Using modern jaguars from Mazak et al. (2013) as isometric comparison, these specimens weighed 130 kg, 130 kg, and 170 kg respectively. From the p3 reconstructions, the largest P. toscana and P. gombazoegensis of Bisnik were 260 mm and 295 mm, respectively. The largest P. gombazoegensis CBL was 300 mm. These measurements translate to 85 kg, 120 kg, and 130 kg, respectively. Leopard-based isometric comparisons showed a much heavier animal. I will stick to the jaguar based estimations for now as it seems the common agreement is that these are old jaguars, as well as the fact that I used jaguar data for the CBL reconstructions. van Valkenberg's formula found the Bisnik m1 specimen to weigh 145 kg. Marciszak corrected this value in accordance with Hemmer by 1.20x to give a value of 180 kg. The correction has a statistic issue however, as allometry does not allow a single correction factor to be accurately used as we are actually on an exponential rather than linear scale. Hemmer (2004) predicts P. gombazoegensis to weight 190 kg at the high end. Unfortunately I don't know his equation, but it most likely used the common approach of using literature masses with personal measurements. With that, does anyone know any detailed measurements of leopard skulls, including dentition? I'd like to explore my finding that the leopard-based estimate for these cats was much greater.
Meet Uyan and Dina, the two frozen Cave lion cubs have been officially named.
http://www.dailymail.co.uk/sciencetech/article-3321735/Meet-Uyan-Dina-10-000-year-old-cave-lion-cubs-close-pictures-ancient-predators-unveiled.html Maybe it is a male cub and a female cub?
Great news, some interesting quotes:
1. The cubs 'are complete with all their body parts: fur, ears, soft tissue and even whiskers'. They are, he claimed, unique in the world, the most complete remains of cave lions ever found. 2. 'I would not talk about cloning now. Our main task here is to decipher the genome and to work with it. I think that speculation about cloning is very premature.' 3. Comparing with the modern lion cubs, we think that these two were very small, maybe a week or two old. The eyes were not quite open, they have baby teeth and not all had appeared. 4. They definitely differed from the modern lions, and we think there should be something that allowed them to adapt to the climate. 5. We suppose that the cave lioness behaved like the modern lioness in pride. 'It seems like she gave birth to the cubs and hid them in cave or hole to protect from the hungry lion'. 6. Cave lions - Panthera spelaea (Goldfuss) - lived during Middle and Late Pleistocene times on the Eurasian continent, from the British Isles to Chukotka in the extreme east of Russia, and they also roamed Alaska and northwestern Canada. Source: http://siberiantimes.com/science/casestu...rian-cold/ Interestingly, at difference than the modern lion, this young cubs did not have any spot in they fur, and the adult ones seems to have a reddish color, not the tawny yellow that the modern specimens. Hopefully these new specimens and they DNA would settle the issue of "species vs. subspecies".
I think the Cave lion should be classified as two subspecies; the European subspecies and the Siberian subspecies.
And the Alaskan Cave lion should be considered as the North American population of the Siberian subspecies.
Smilodon populator - A new fossil and questions about bone robusticity to cursoriality, among other issues
Browsing through some older document, I found one of great insight to Smilodon fatalis and S. populator morphology, Relationships between North and South American Smilodon by Björn Kurtén and Lars Werdelin. The differences between the forms were analyzed by this work, and you can read up on it in the attachment. Postcranial anatomy interests me the most. For one, I found a record size humerus of 410 mm. Isometrically comparing to the bear humerus of 400.5 mm, this specimen would be about 470 kg (a post on p. 1 explains why bears may be better isometric basis for this species). This humerus puts S. populator back at the top of felid weights. But there's a caveat. The same document found that "the forelimb of S. populator is somewhat longer, relative to the hindlimb, than in S. fatalis. Such a lengthening of the forelimb is a characteristic of the open plains." An example of this observation is the fact that lion has a proportionally longer humerus and ulna compared to the hindlimb bones, being the only big cat living almost exclusively in the open plains. This morphological characteristic results in overestimation of mass from all bone measurements when comparing to a more average proportional individual. Bone length overestimates because the bone is disproportionately long, and width dimensions overestimate because the width is more for accommodating running stress than muscle in such cases. The brown bear has much shorter frontlimbs than hindlimbs are compared to S. populator, and a bit shorter proportions compared to S. fatalis. In this form, S. fatalis is more robust and bear-like than S. populator, but neither were probably as muscular as a bear, but rather some of the bone width was more for running stress similarly to how lions bones have widened so greatly as compared to other cats. With that, the S. populator estimation using the brown bear as the base is probably an overestimate, or faulty at the least. S. fatalis reconstructions from a brown bear may be a bit less of an overestimate. Smilodon would lack the posterior weight the bear would in the this areas due to the FL/HL discrepancy, and thus the two species are not analogous, at least for humerus calculations. It is very possible the opposite effects of mass estimation would occur if a brown bear femur is being compared to the proportionately shorter Smilodon femur. Smilodon's femur is proportionately much larger than its tibia compared to all pantherines by a long ways. Its humerus is also proportionately larger than its ulna, a ratio only matched by the very robust leopard and jaguar. The longer proximal bones is indicative of the fact that Smilodon is indeed much more heavily built than the lion and the tiger, and somewhat more heavyset than the leopard and jaguar. From this, maybe the best route of Smilodon reconstruction would be one width dimensions and/or the length dimension of the bone, either allometrically or isometrically compared to only jaguars and leopards. The type of bone being used would also have to be taken into account to predict the accuracy of the estimation. Forelimb estimates may be overestimates somewhat, and vice versa for hindlimb estimates.
It is pretty interesting that the Smilodon fatalis is built closer to a Pantherine cat, while their South American cousins are built like Hyena with a slope back.
Because the Pleistocene North America was like a prehistoric Serengeti, we can find out many comparable species from the Elephantidae to the Bovidae such as the Mammoth and the Bison. The Smilodon fatalis could be built like the modern African lions for the purpose to running down the preys similar to those modern African preys, while the Smilodon populator was built with more stamina to running down those primitive exotic preys in the Pleistocene South America. 
When we are comparing these cats to Hyena, is it because they also have a more rigid spine?
I recently learned as to what morphological advantage a hyena build has compared to a cat build. When comparing them, a hyena has a more rigid or stiff spine with large deltoids, traps, lats etc. (back and shoulder muscles) which allow them to become "battering rams" which is why they seem to "steamroll" their way into a carcass if another predator is there unless its a larger cat of course, than a bit of finesse is required. (12-04-2015, 09:57 PM)Pckts Wrote: When we are comparing these cats to Hyena, is it because they also have a more rigid spine? They can only pursue their preys in a straight line, but when their preys has made a sharp turn, they would lose the track. (12-04-2015, 11:54 PM)GrizzlyClaws Wrote:(12-04-2015, 09:57 PM)Pckts Wrote: When we are comparing these cats to Hyena, is it because they also have a more rigid spine? Was this the hypothesis on the Smilodon cats? If that is the case, they would obviously need to hunt slower moving prey aka large animals or resort to scavenging much like hyena today.
Has there ever been any talk on lung capacity of these cats?
I wonder if they adapted the long hunt or were they ambush predators?
It is harder to study on the anatomy of the extinct animals than the extant ones.
But I heard that the South American Populator was built for stamina, while their North American cousins are more akin to the modern big cats, the speed over the stamina. |
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