WildFact
›
Information Section
›
Extinct Animals
›
Pleistocene Big Cats
Freak Felids - A Discussion of History's Largest Felines
Freak Felids - A Discussion of History's Largest Felines
|
Freak Felids - A Discussion of History's Largest Felines
|
Here is another wonderful article.
Date: July 11, 2012 Source: Bristol University Summary: Modern cats diverged in skull shape from their sabre-toothed ancestors early in their evolutionary history and then followed separate evolutionary trajectories, according to new research.  *This image is copyright of its original author Fossil skull and lower jaws of a sabre-toothed cat, Smilodon fatalis, from the La Brea tar pits of California, USA. Credit: Image by Simon Powell, School of Earth Sciences Short Description The study also found that the separation between modern domestic cats and big cats such as lions and tigers is also deeply rooted. Dr Manabu Sakamoto and Dr Marcello Ruta in the School of Earth Sciences studied the skull shape of extinct sabre-toothed cats, modern (conical-toothed) cats and prehistoric 'basal' cats (ancestors of modern cats). This is the first time these three different types of cats have been analysed together in a single dataset. The researchers quantified skull shape by taking various measurements, adjusting these measurements for size differences, then investigating the distribution of cat skulls in shape-space. By estimating ancestral positions through shape-space and time, they investigated patterns of skull shape evolution across the cat family tree. They found an early and conspicuous divergence between the conical-toothed cats and sabre-toothed cats, with all sabre-toothed cats being more closely related to each other than they were to modern conical-toothed cats. There was also a marked separation between modern small-medium cats (that is, the domestic cat and its close relatives, the cheetah, puma, ocelot, serval and lynx) and modern big cats (such as the lion, tiger, leopard and jaguar), with a divergence in skull shape early in their evolutionary history. This means that small-medium cats and large cats followed different evolutionary trajectories with respect to skull shape. Dr Sakamoto said: "Our study is the first to determine the interrelationships between modern conical-toothed cats, sabre-toothed cats, and some basal cats. "It also highlights how simple measurements can be used not only to investigate shape-space distribution, but also to successfully discriminate and identify different cat species -- this could be useful for museums who may have as yet unidentified cat specimens in their collections. "Lastly, our results show that differences in cat skull shape have deeply rooted evolutionary histories, first between the sabre-toothed and conical-toothed cats, and then between small-medium and large cats." Story Source:The above story is based on materials provided by Bristol University. Note: Materials may be edited for content and length. Journal Reference:
Original Source:http://www.sciencedaily.com/releases/2012/07/120711141010.htm 
The sabertooth cats were the earliest group that branched off from the Felidae family.
Yes, This article also suggest this. But What i found more interesting is that the medium-small size cats and big cats followed different evolutionary path with respect to skull shape.
  *This image is copyright of its original author 6/10/2015 edit note: I am adding the comparison image to the first page as a nice title picture to the topic. 10/30/2015 - I am introducing a table of contents to this: Format: Topic (page number(s) in parenthesis) Table of contents Smilodon populator mass (1) Large Tiger skulls of today (1) Mass vs. Total Length (2) Guate's Fact Sheets (2) Large cat estimates (somewhat outdated) (3) The megafauna of the Sunda shelf (3) What is robusticity and density of cat? (4-5) Javan Tiger Paws (5) The Ngandong femur (5) Smilodon II (5-6) von Reichenau's giant lion (7) How to measure long bones (7) Homotherium crenatidens (8) Manchuria's Mystery Mandible (10) A new cave lion fossil (15) Tiger geographic expansion (17) New findings from Ural (19) Fieryeel's new Solo river canines and new Chinese canine (23-32) Machairodus' skull (35) A cave lion in the flesh (nearly) (35) Acinonyx pardinensis morphology (37) Jaguars of old morphology (38) Follow up of frozen cave lion cubs (38)
We are not sure about the vague assumption of the 250cm head+body of Panthera atrox, also we don't know it is between peg or over curve.
But based on the femur measurement, we can assure that the largest Panthera atrox specimen discovered so far is dimentionally smaller than the 480mm femur specimen or Baikal (being physically identical to the 480mm femur specimen). As tigerluver gave the estimation of 415kg for the 480mm femur specimen, while Baikal was 386kg. But keep in mind that when they weighed Baikal, he was already 12 years old and past his prime. In a pic where he climbed up to a tree, he was way more athletic and also looked younger and more muscular. He should definitely weigh more, maybe up to 900 pounds. So i think Baikal should weigh around 900 pounds during his prime, same as the largest Ngandong specimen. Ngandong tiger and Amur tiger/other modern tigers should be proportionally similar to each other.
Upon Sanjay's request, I'll start this thread. I've some spare time these days, should be fun!
I think it would be interesting to discuss the evolution and morphology of prehistoric cats. I'll start by transferring my P. s. fossilis post here, and be back later. (06-22-2014, 10:27 AM)'tigerluver' Wrote: Dug up an old post I wrote from yuku, I haven't worked with cave lion data in a while. Another old post of mine which also discusses size estimation methods and the derivation of my Ngandong tiger estimate. Exceptions to Isometry I'd like to point out why the isometric approach is often times invalid. Data shows that not everything is isometric. Here is an example, based on tiger femur measurements and respective body masses: We will estimate the mass of CN5698 (P. tigris, FL = 411 mm, actual mass = 230 kg) with the isometric method using 3 other specimens. Estimations using isometry: 1. Specimen used for comparison measurements are FL = 408.5 mm and M = 225 kg. Applying isometry, the estimated mass is 229 kg. 2. Specimen used for comparison measurements are FL = 360.5 mm and M = 145 kg. Applying isometry, the estimated mass is 215 kg. 3. Specimen used for comparison measurements are FL = 341.5 mm and M = 115 kg. Applying isometry, the estimated mass is 200 kg. I won't bother giving the total average, as that is not helpful to the point being explained. Note, the smaller the individual used for comparison, the smaller the estimated mass. This means that body mass grows at a greater rate than cubically in respect to femur length. Now let's estimate the mass of small specimen with isometry, the specimen is labeled as CN5669 (P. tigris, FL = 341.5 mm, M = 115 kg). 1. Specimen used for comparison measurements are FL = 408.5 mm and M = 225 kg. Applying isometry, the estimated mass is 131 kg. 2. Specimen used for comparison measurements are FL = 360.5 mm and M = 145 kg. Applying isometry, the estimated mass is 123 kg. 3. Specimen used for comparison measurements are FL = 411 mm and M = 230 kg. Applying isometry, the estimated mass is 132 kg. Note that now the larger specimens are giving an overestimation of mass when compared with the small specimen. Had body mass scaled to femur length cubically, this would not have been the case. Though, again, as body mass grows a greater rate than cubically in respect to femur length, larger specimens give overestimations when compared with smaller specimens. This is where regression comes into play. The scale factor (which is the slope of line of best fit if scaled logistically) represents whether or not mass grows isometrically (cubically). Logistically scaling and graphing the data produces the scale factor of 3.6865. Using the cube law, substitute this scale factor for 3, and note how the estimates become much more accurate. What I have just explained is part of the basis for the use of linear regression rather than isometry in recent documents. It is interesting to note that within species(not genus or family, thus why Christiansen and Harris (2005) formula had scale factors of less than 3) from bears to tigers, mass to femur length seems to grow at a greater rate than cubically. Finally, the full equation derived from the 4 specimens cited in this posted is as follows: log(body mass) = 3.6865*log(femur length) - 7.273. Pertaining to our topic, this produces a mass of 409 kg for our largest specimen of P. t. soloensis. Also, a little fun fact, Panthera tigris soloensis roughly translates into "solo tiger," similar to how Homo erectus soloensis mean solo man.
What's your opinion about the comparison between Baikal and the Ngandong tiger?
I agree that Baikal is probably as close as the Ngandong tiger specimen as it gets. The weight discrepancy between my estimate and Baikal is only 6%, which is easily explained by deterioration with age.
Do you think that Baikal is a captive mutant or he is simply the reproduction of the Amur's gigantic genetic remain in the captivity?
If he is the later one, then it would make sense to say that the Pleistocene tiger was about the same size as the largest modern tiger. Since the Pleistocene lion and the modern lion don't belong to the same species, then this also explains why the modern tiger can retain its size compared to its Pleistocene counterpart, while the modern lion simply cannot.
I think he's a mix of the two. His size is well out of the range of even a large modern tiger. But his freak size may in some way be connected the tiger's historic maximum, freak size.
I feel the Ngandong tiger at max sizes was probably larger than modern tigers. Out of a handful of specimens, we already have such a large find. Thus I'd be inclined to say the 409 kg specimen was likely not a freak, rather something like 300 kg modern tiger. The Wahnsien tiger is much more similar in size to our modern tigers. I reconstructed the skull of a large molar we've discussed before (cannot remember which one), and my equations estimated a weight of about 313 kg, similar to our largest modern tigers. Good last point. The size discrepancy between the modern lion and cave lion indicates to me that the two species could not interbreed, and thus modern lions do not have those giant genes in the mix. On the other hand, the Ngandong tiger was a tiger , and it could freely interbreed with the modern tiger we know. It's interesting that we've found 3 specimens of P. s. fossilis that approach 400 kg. It might be safe to say these specimens probably weren't freaks either. I feel that both the Ngandong tiger and the early cave lion probably give Smilodon populator a run for it's money in terms of size. I'll try to write might next about my thought on Smilodon.
Before the Toba eruption, the Ngandong tiger's homeland was connected with the Asian mainland.
With the geographic proximity, i think the Ngandong tigers may be able to interbreed with its Asian mainland cousins AKA the Wanhsien tigers, the direct ancestor of the modern tigers. Maybe this could be the reason that we have some freak individuals of the Wanhsien tigers in the private collection, but also the modern genetic twin such as Baikal.
Now I'll share my thoughts of Smilodon, Smilodon populator specifically.
The largest specimen estimate for S. populator is 358 kg by Christiansen and Harris 2005 based on a humerus. I have some concerns over the estimates of this study. Christiansen and Harris themselves cite and state that allometry is more often positive, thus bigger bone should be a proportionately heavier animal. Though, their data says otherwise. Working with the numbers I've made two observations: 1. On the species scale, the smaller big cats are much stouter than the larger ones, and thus negative allometry as species (note, not individual) size increases. 2. On the individual scale, individuals of a species relate to each other with positive allometry. Bigger animals are stouter within a species. Now it gets messy and confusing. To try to compensate for this, I decided to limit the database to only lion and tigers on the basis that these two species are closest in size to the prehistoric giants. Using tigers and lions as the database works under the assumption that the fossil in question is in the middle ground in terms of built (tigers are significantly heavier in proportion in lengths and even width measurements in some case as tigers have thinner bones yet heavier masses). The smaller cats are simply too proportionately different in Christiansen and Harris's database (althoughg Anyonge finds positive allometry across the board, on a species and individual scale, though he did not publish his database, so further analysis is impossible). From there, I generate the log equations to estimate mass. There is one major problem, the tiger and lion database derivation works well only in the case of bone lengths, but when applied to bone widths, everything so haywire. The reason? Tigers have thinner bones, yet are heavier, and vice versa for lions. As the database is composed of more small tigers, the allometry becomes extremely negative, to the point which I consider unreasonable. This hindrance also extends to the Christiansen and Harris equations. The main culprit for this problem is the tiger's oddness. Its specimens lie far right, at the largest weights, yet its diameters are lower than they should be. This creates a stronger false negative allometry for the other species, thus giving lower estimates. Therefore, I feel that Christiansen and Harris's estiamte for the largest S. populator may be an underestimate. Like we compared Baikal to the giant Ngandong specimen to validate an estimate, let's compare this Smilodon bone to some extant specimens. The parameters (in mm) of this humerus bone that I'll discuss are: Length: 387.5 Least circumference: 155 Forget comparing this bone to a cat for now, it's way too stocky. The stockiness is probably not due to cursoriality either, as Smilodon wasn't much of a runner with its bobtail and for the fact that the relatively stout boned cursorial lions of today are not even close to this fossil humerus. Let's compare these measurements to a Grizzly humerus (in mm): Length: 400.5 Least circumference: 146.25 Mass: 435.5 kg The Smilodon humerus is, interestingly enough, even wider than the Grizzly bone even though it is shorter. From this, Smilodon was not built like a bear, it was built like a Smilodon. Now the point we all love, mass. The Smilodon humerus is about 3% shorter and 6% wider than the bear humerus, leading me to believe we have a specimen which probably weighed around the bear's mass. Of course, Smilodon being built differently from a cat and a bear in terms of dimensions (e.g. the sloping back) would likely have an effect on mass. But from what we have available, the bear bone is a good reference point. So, what do you guys think?
This is really great discussion going on. I like the information. TFS tigerluver and grizzlyclaws
How about the Duisburg specimen? Could he be a modern genetic twin of the Wanhsien tiger?
It is interesting to see so many modern incarnations of the prehistoric tigers.
Amur tigers as a whole share some similarities to Wahnsien tigers, especially the proportionately large head, which the Duisburg specimen was an extreme example of. Though, isn't it said that the indochinese tiger was the earliest of what we have left now? Maybe Amur tigers are more primitive than thought.
|
| Users browsing this thread: |
| 1 Guest(s) |