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Ancient Jaguars
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Did the cougar species originate in North or South America or even in Eurasia (if it was there at at all)?
Here is a cast of a jaguar pugmark found in Craighead Caverns, Eastern Tennessee. A rule is to the right for scale. The picture is from this pdf.
 *This image is copyright of its original author Large jaguar bones were found in the caverns in 1939, and in 1940 George Simpson, the author of the linked paper, visited the caverns and collected more bones. He also descried several footprints. The bones may belong to more than one individual, as, I suppose, may the footprints. When discussing the origin of the tracks, and the assignment of their provenance to jaguars, the author writes the following: "Large recent male pumas of the F. concolor oregonensis or hippolestes group may leave tracks as much as 90 mm. across the three middle toe pads, but probably never much exceed that size. Since this dimension is about 120 mm. in the cave prints, these certainly could not have been made by any recent puma. They could have been made by a jaguar of about the maximum size for males of the largest South American races, and this is about the size of the bones found in Craighead Caverns. " Web publications, including Simpson's paper, variously describe the first recovered bones from Craighead Caverns as belonging to a "very large", "giant" or "great" jaguar, but this passage suggests that the animal in question was about the size of larger modern Pantanal specimens, which, honestly, seems like what really should be expected for most P. o .augusta and P .o. mesembrina, taking the morphometric studies done by various authors into consideration. The size descriptors used by Simpson are evidently in comparison to the smaller modern jaguars of North America, not to the most imposing examples of the species from South America.  *This image is copyright of its original author I don't think this specimen has been posted in this thread before. The image is from this pdf. According to the text, the prosthion-basion length of the skull is 227.8mm, or around 8.969 inches. I attempted to calculate the greatest length of the skull based on its apparent length relative to the scale bar in the photo. My results fluctuated but average out to around 10.25 inches. This might not be a very reliable method, but either way the skull is clearly well within the range of modern jaguar skulls length-wise. The text describes this specimen as " from a very large jaguar", but it's worth noting that, according to the same text, Kurten (1973: Fig. 1) briefly reported on this skull and concluded that it was a female jaguar on the basis of its relatively small size for P. onca augusta. Really though, measurements of augusta and mesembrina skulls have already been posted on WildFact, and they show skulls within the range of those of modern jaguars, so this is nothing new. I'm just making this post for people more unfamiliar with the late Pleistocene large jaguars.  (09-27-2020, 06:57 AM)KRA123 Wrote: Here is a cast of jaguar pugmark found in Craighead Caverns, Eastern Tennessee. A rule is to the right for scale. The picture is from this pdf.120mm print would be nothing to extraordinary, 127mm prints are a good sized male jaguar, usually in that 120-130kg range.
I'm wondering if somebody here could help me. I'm looking for a particular table with measurements for South American jaguar fossil skulls. I know that one such table was posted in this thread, but all the measurements in that one are below 300 mm; the table I'm thinking of had a few entries over 300 mm, but I cant find it for the life of me. I can't remember if it was posted here by @GuateGojira or @epaiva or someone else , or if I just found it in my own personal research; heck, now I 'm not convinced that it exists at all. Does anybody here know of such a table?
 (12-21-2020, 01:00 AM)Balam Wrote:I don't think comparisons like this are generally accurate knowing what we now know about the real sizes of Pleistocene North American jaguars, the giant specimen reported from the Oregon caves notwithstanding. P.S. I am currently working on getting information about that specimen, but it may take a while. I've ben told that something has been in the works for a while regarding it. (12-21-2020, 06:58 AM)KRA123 Wrote:(12-21-2020, 01:00 AM)Balam Wrote:I don't think comparisons like this are generally accurate knowing what we now know about the real sizes of Pleistocene North American jaguars, the giant specimen reported from the Oregon caves notwithstanding. Do you mind elaborating on the Oregon cave fossil notwithstanding? So far the only Pleistocene remains for Panthera onca that are disputed are those from the milodon cave in the Patagonia, that I know of at least. There are also records of canine teeth from Florida with a length of close to 9 cm, much greater than anything present with extant jaguars and closer in size to extant mainland tiger forms, especially considering that jaguars have shorter canines relative to their size.  (09-27-2020, 01:39 PM)KRA123 Wrote: I'm wondering if somebody here could help me. I'm looking for a particular table with measurements for South American jaguar fossil skulls. I know that one such table was posted in this thread, but all the measurements in that one are below 300 mm; the table I'm thinking of had a few entries over 300 mm, but I cant find it for the life of me. I can't remember if it was posted here by @GuateGojira or @epaiva or someone else , or if I just found it in my own personal research; heck, now I 'm not convinced that it exists at all. Does anybody here know of such a table? Were you able to ever find this? I searched Merriam and Stock to see if that was it but the skulls weren’t that large. (12-21-2020, 07:13 AM)Balam Wrote:(12-21-2020, 06:58 AM)KRA123 Wrote:(12-21-2020, 01:00 AM)Balam Wrote:I don't think comparisons like this are generally accurate knowing what we now know about the real sizes of Pleistocene North American jaguars, the giant specimen reported from the Oregon caves notwithstanding. In 1995 a jaguar fossil was found in the Oregon caves. This fossil was reported by the press to have a skull with a length of 14 inches. However, no thorough description of this specimen has yet been published, and apparently some of the skull is still cemented to the cave floor, so I consider this information to be tentative until we get something more concrete about the specimen. This specimen has been described in web articles as being 450 to 500 pounds, and that probably helped popularize the notion that augusta was the same size as adult mainland tigers. Considering it's the northernmost jaguar fossil found in America, any unusually large dimensions it possesses might be due to Bergmann's rule. On the Orgeon caves Facebook page I saw somebody post that this jaguar was the size of a young Bengal tigress. I have more to say about this specimen, but that will have to wait until a later post. (12-21-2020, 07:30 AM)tigerluver Wrote:(09-27-2020, 01:39 PM)KRA123 Wrote: I'm wondering if somebody here could help me. I'm looking for a particular table with measurements for South American jaguar fossil skulls. I know that one such table was posted in this thread, but all the measurements in that one are below 300 mm; the table I'm thinking of had a few entries over 300 mm, but I cant find it for the life of me. I can't remember if it was posted here by @GuateGojira or @epaiva or someone else , or if I just found it in my own personal research; heck, now I 'm not convinced that it exists at all. Does anybody here know of such a table? No, I never found it. I'm starting to suspect that it doesn't actually exist, but if I do find it eventually, I'll post it.
@KRA123 I agree with you on the Oregon cave skull, while more information is required to reach a solid conclusion, all decks are on the table as it pertains to that particular specimen. We've seen tremendous overlap with Pa. onca and Pa. atrox remains, so to be cautious from jumping to conclusions is reasonable.
That being said, the opposition in placing P. onca augusta as a different species based on craniometric analysis is not as strong as what has been publicized for Pa. onca mesembrina by Chimento et al. in 2017. Even with the latter, that those remains analysized belong to Pa. atrox remains a contested claim. In regards to Pa. onca augusta remains, the canine teeth mentioned by me before was posted by the account "Prehisotirc Florida" on Instagram which is run by a curator of fossil remains from the state. The measurements and comparison with Pa. atrox are foud below (credits to epaiva for originally posting this):  *This image is copyright of its original author  *This image is copyright of its original author More remains for a Pleistocene Pa. onca specimen can be found at fossil action Paleo Enterprise with its respective measurements:  *This image is copyright of its original author  *This image is copyright of its original author In both cases, the length of the canines puts it in the range of what is seen with extant lions and tigers, with the first fossil representing a particularly large canine. In terms of scientific data, the first widely available publicized paper on the species comes from Schultz et al (1985), from the University of Nebraska, the paper was titled: A Pleistocene Jaguar from North-Central Nebraska, it goes in-depth about the skull measurements of one particular specimen, thout to belong to a female. The complete dimensions of the skull were not disclosed, but the lengths for points within the skull between the border of the palette and the posterior of the snout are given. I don't really know of similar measures taken for tigers or lions to compare, but the paper mentions these values as particularly large for an extant jaguar, while on par with different skulls allocate to Pa. onca augusta examined by Schultz previously:  *This image is copyright of its original author  *This image is copyright of its original author A more recent paper, The large jaguar that lived in the past of México: a forgotten fossil, goes into more detail as it pertains to remains found in Mexico for a Panthera species that shows craniometric proportions of a jaguar, but with much larger proportions. In this case, only a mandible could be studied:  *This image is copyright of its original author  *This image is copyright of its original author The doubt in placing these remains into Pa. onca is derived from the proportions of the skull, which is why the classification of augusta is put in place as the dentition from these specimens do not show affinity with those of the cave or American lion.  *This image is copyright of its original author Material: a mandible with molars and canines of a felid of great size, from the Pleistocene in Jalisco, Mexico. I would also challenge the idea that Bergmann's rule is actually a scientific theory (i.e. has been proven beyond a reasonable doubt), there's plenty of scientific work publicized which shows that the correlation between the increment of mass in an animal and the latitude in which those species live, is not directly correlated by their proximity to the poles, as it is widely believed. We can discuss this further if you want, but to conclude my position on the topic at hand, there seems to be more than enough data to suggest larger sizes for Pleistocene jaguar forms in North America, baring that the difference in the skulls and dentition of Pa. onca, atrox and spelaea can all be discerned thanks to the abundance of fossil records from the last two. (12-21-2020, 09:14 AM)Balam Wrote: @KRA123 I agree with you on the Oregon cave skull, while more information is required to reach a solid conclusion, all decks are on the table as it pertains to that particular specimen. We've seen tremendous overlap with Pa. onca and Pa. atrox remains, so to be cautious from jumping to conclusions is reasonable.Check my post #33 in this thread, I posted some information about the UNSM 1,104 skull. It's within the size range of extant jaguars. Definitely Bergmann's rule is controversial, I was just spitballling. Anyway, it is important to determine which modern jaguars the fossil are being compared to when they are described as particularly large. I recently read a study where modern jaguars were compared to Rancholabrean and Irvingtonian specimens, as well as one particularly large South American individual. If I remember correctly, the large modern individual turned out to be larger than both the Rancholabrean and Irvingtonian averages. Also, consider that the Oregon caves page described the 1995 jaguar fossil individual (which apparently has proportions similar to a modern jaguar) as being the same size as young Bengal tigress; well, a huge modern Jaguar like Lopez should also be around the size of a Bengal tigress, right? Unfortunately, I don't have the time to go look for or write about that study right now, so i think we will have to agree to disagree, at least until a later date.
@KRA123 we can continue this conversation at a later time, if you could link the recent study where the measurements of modern jaguars are taken into consideration that could help us paint a broader picture of the claims at hand.
With the recent data we have on the largest Pantanal jaguars, one could deduct that the largest males (Edno, López, Joker, etc.) represent individuals who have shown the potential of reaching prehistoric proportions under the right ecological and genetic factors, but for now I think we haven't seen any living jaguars attain the maximum sizes estimated for Pleistocene forms, baring those estimates are accurate. |
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