Ancient Jaguars

[Balam]

(04-26-2021, 01:44 AM)Balam Wrote:

(04-26-2021, 12:27 AM)tigerluver Wrote:

(04-15-2021, 04:24 AM)Balam Wrote: This study hasn't been posted here but a paper that studied the genetic relationship between extinct Pleistocene Patagonian taxa through phylogenetic reconstructions based on mitochondrial DNA concluded that P. o. mesembrina was well within the genetic markers of P. onca, not P. atrox. The likelihood that Chimento and Agnolin's (2017) paper did in fact relate to P. atrox becomes even less substantiated considering that the genetic data from this species is completely lacking from the area. The cave paintings do not depict lion-like creatures (but they do depict spotted felids), and the remains of P. atrox have not been found in other South American or Central American sites southern from Mexico to infer a proper migration, as we do have with other species. 

Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions during the Last Deglaciation, by Metcalf et al (2016):

*This image is copyright of its original author

*This image is copyright of its original author

While the modern jaguar forms a monophyletic species, during the Pleistocene P. o. mesembrina could be genetically distinguished as a different subspecies, but not being different enough to be classified as a distinct species altogether. This is why using craniometric data from modern jaguars to rule out the possibility of P. o. mesembrina belonging to a different species is flawed, as the morphology of P. onca would vary from this other subspecies, and the environmental factors that could've contributed to the greater size on the Pleistocene form (such a larger prey availability and biomass during) are not present in the native ranges of extant jaguars. These ecological differences are key in distinguishing the morphological differences the two subspecies depict.

*This image is copyright of its original author

From the supplementary data:

*This image is copyright of its original author

*This image is copyright of its original author

If we are to take Chimento and Angolin's work with a degree of plausibility, we should also take into consideration other data that points towards the contrary with stronger DNA samples as opposed to ambiguous skull markers. The idea that P. atrox made it as far as the southern tip of the Patagonia is at best very dubious.

Furthermore, I found their work to lose credibility considering the degree of speculation in which they went to describe the supposed appearance of "P. atrox" based on factors that may have not been related at all, such as fur found on the caves which led them to believe it had a "reddish" coating, something that we do not see i the frozen remains of cave lion cubs.

Sorry I got to this so late. Great paper! 

I was comparing the datasets and they are from the same sites mentioned by Chimento and Agnolin (2017). The lack of P. atrox in the same can obviously mean there was no P. atrox or that the frequency of P. atrox was much less and thus it wasn't represented in the small random sample. The sample size is decent at 17.

I could not find it so I was wondering if you were able to find a divergence date between P. onca and P. onca mesembrina in the study? It would be helpful in our reconstructions.

I also have the legends for the excellent comparative photos in Chimento and Agnolin (2017). A is of course the "P. onca mesembrina" skull. B-D is P. leo, E is P. atrox, F and R-Y are extant P. onca, G-H are the fossil P. onca.

Here are the figures again:

*This image is copyright of its original author

*This image is copyright of its original author

From these comparative photos, Chimento and Agnolin (2017) are correct in the assertion that the incisive foramina of the skull in question are visible in superior view. Extant jaguars do not have this trait and would be solid evidence against the mystery skull being of the extant P. onca form. Even in the fossil P. onca we see the incisive foramina are not visible from the superior view. They also assert that the snout is indistinguishable from P. leo/P. atrox. To me, the rostrum looks more stout then pretty much all the other specimens in the photo except maybe P. spelaea (J) and the fossil P. onca (G and H specifically). Stoutness is however a more jaguar-like trait. I will note that the damage to the snout also makes it harder to ascertain the true stoutness of the rostrum.

It could be fair to say the skull does not group well with comparative specimens as its traits are a unique combination. If "P. onca mesembrina" is a genetically distinct taxon related to extant P. onca, this could make sense. I also want to highlight a new species of P. balamoides in this discussion. To quote, "Panthera balamoides sp. nov. combines characters of smilodontids and Panthera, with more similarities to Panthera onca." This asks the question if the "P. onca mesembrina" skull and P. balamoides are of the same species.

Quote:I was comparing the datasets and they are from the same sites mentioned by Chimento and Agnolin (2017). The lack of P. atrox in the same can obviously mean there was no P. atrox or that the frequency of P. atrox was much less and thus it wasn't represented in the small random sample. The sample size is decent at 17.

Yes, most of the analyzed remains come overwhelmingly from the Mylodon cave which was the site used in Chimento and Agnolin's study. This is really good because it keeps us from inferring if the two genetic data gathered from Metcalf et al. directly correlates with the 2017 paper.

Quote:I could not find it so I was wondering if you were able to find a divergence date between P. onca and P. onca mesembrina in the study? It would be helpful in our reconstructions.

Unfortunately the study didn't mention the divergence date between both subspecies beyond their genetic proximity and how they relate to other pantherines. Perhaps this data will come along in further studies in the future. My guess is that the genetic split between P. onca and P. onca mesembrina would be between 300,000 at most to 150,000, if we use similar evolutionary patterns based on the relationships between the subspecies of P. leo.

Quote:From these comparative photos, Chimento and Agnolin (2017) are correct in the assertion that the incisive foramina of the skull in question are visible in superior view. Extant jaguars do not have this trait and would be solid evidence against the mystery skull being of the extant P. onca form. Even in the fossil P. onca we see the incisive foramina are not visible from the superior view. They also assert that the snout is indistinguishable from P. leo/P. atrox. To me, the rostrum looks more stout then pretty much all the other specimens in the photo except maybe P. spelaea (J) and the fossil P. onca (G and H specifically). Stoutness is however a more jaguar-like trait. I will note that the damage to the snout also makes it harder to ascertain the true stoutness of the rostrum.

 
I think this area becomes more tricky to assess and where most of the controversy centers around, hence my dissatisfaction with Chimento and Agnolin's work relying almost entirely on ambiguous skull markers to make very bold claims. While the incisive foramina are certainly visible on the P. onca mesembrina skull, the conclusion from the 2017 study concerning the muzzle is in my opinion completely erroneous. As you said the snout in P. onca mesembrina is more stout than in P. leo or P. atrox and almost resembles perfectly the H skull belonging to fossil P. onca. Furthermore, while the skull for P. onca mesembrina is not complete, one can tell from looking at the beginning of the zygoma (and based on the rendition performed in the study itself) that it would've been significantly wider than the zygomatic arches of P. leo and P. atrox. In fact, the difference between P. onca mesembrina and P. atrox is this regard is the most pronounced in the entire sample, while it matches almost perfectly with the remains of fossil P. onca, IMO. 

Quote:It could be fair to say the skull does not group well with comparative specimens as its traits are a unique combination. If "P. onca mesembrina" is a genetically distinct taxon related to extant P. onca, this could make sense. I also want to highlight a new species of P. balamoides in this discussion. To quote, "Panthera balamoides sp. nov. combines characters of smilodontids and Panthera, with more similarities to Panthera onca." This asks the question if the "P. onca mesembrina" skull and P. balamoides are of the same species.

Personally, I think that the traits present in the P. onca mesembrina skull align more closely to P. onca than any other pantherine, granted that some differences are appreciated but this could be explained by morphological adaptations that evolved from the basal P. onca as the mitochondrial data has concluded them to be different subspecies. 

In regards to "P. balamoides", this was a potential species I was very interested in some time ago as it would've expanded the range of the pantherine felids in the New World considering many people thought this was a different species from P. onca, P. atrox or P. spelaea. However recent studies strongly point towards the possibility that these remain in fact belong to the ursid Arcotherium and it was never a true felid after all. See Yucatán carnivorans shed light on the Great American Biotic Interchange, by Schubert et al. (2019).

Another layer that puts into question the existence of P. atrox in the Patagonia is the lack of cave paintings associated with this taxon in contrast to jaguar paintings. We discussed the ones from the Mylodon cave some time ago, but here's some more from adjacent areas. These paintings were described in the paper La Cueva de los Yaguaretés by Ramirez in 2002 from the Santa Cruz province in the Argentine Patagonia:

*This image is copyright of its original author

And likewise from Santa Cruz Arte rupestre pleistoceno de Santa Cruz, Patagonia Argentina, Paunero (2012):

*This image is copyright of its original author

*This image is copyright of its original author

Granted that we do not have radiocarbon dating for these specific rock paintings which makes it hard to assess their temporal proximity to P. onca mesembrina and Patagonian post-glacial P. onca, but the depictions are consistent with the cave paintings described by Chimento and Agnolin, with a spotted cat being the common denominator. We know from cave paintings in Europe that local human tribes did not shy away from describing the lion in their art. It is likely that they saw them as extremely important species and held plenty of reverence to them, and we should expect the same phenomenon with human settlements that utilized similar art methods in caves to describe the world around them, as was the case in the Patagonia. Yet we get a complete absence of lion paintings from this region in contrast to the jaguar, this leads me to believe that the relationship between local Patagonian tribes and the jaguar was similar to that of Europeans with cave lions.

We know that Chimento and Agnolin have in their position fur enclaved to a claw and a patch of skin, it would be interesting if they could analyze the genetic composition of those fragments of fur to determine what species they belonged to, rather than liberally guessing. My guess is that they would come back matching Smilodon populator. If further studies like these are not performed by them my suspicions that the conclusions on the supposed presence of P. atrox in the Patagonia by them were simply rushed and may have been driven by bias (wanting to have the presence of P. atrox in South America). I believe that the lack of DNA from P. atrox from Metcalf et al. is a strong enough deterrent to at least put into question the veracity of the claims made in the other paper. 

As it is often said extraordinary claims require extraordinary evidence and Chimento and Agnolin have yet to provide us that.

A quick correction on my part, from Paunero's Arte rupestre pleistoceno de Santa Cruz, Patagonia Argentina paper, the dating for the paintings are in fact inferred and the appearance of P. onca mesembrina is deducted:

*This image is copyright of its original author

"The archaeological record indicates that the first human groups arrived at southern Patagonia at the end of the Pleistocene, these times are characterized by great climatic changes, with fluctuations in flora and extinction processes of fauna (Borrero 2001; Borromei 2003; Páez et al. 1999). If we put aside the dates discussed by the academic community (Goebel et al. 2008; Paunero 2009a; Rubinos Pérez 2003; Waters & Stafford 2007), the evidence indicates that Initial human occupations on the Central Plateau of Santa Cruz were contemporaries of the event known as the Antarctic Reverse Cold Episode (Hajdas et al. 2003; Heusser & Rabassa 1987), related to Younger Dryas from northern hemisphere and that the situation with a trend similar to the current one, it would reflect from 8 ka AP. (McCulloch & Davies 2001; Miotti 2004; Paunero 2009a). Expressed in time ranges and according to knowledge current archaeological, exploratory events and initial colonizing phases
they would be in the range of: 10,000 to 11,200 years 14C BP. (Tables 1-2)."

*This image is copyright of its original author

"Archaeological, palaeoenvironmental and paleontological evidence shows us that in the Central Plateau, the vegetation was of the herbaceous steppe type, that is, with more abundant and tender grasslands that allowed a greater diversity of animals and the survival of large mammal species adapted to these media and are currently extinct, such as the Hippidion saldiasi (equid), the Lama (Vicugna) gracilis (camelid), Hemiauchenia paradoxus (camelid), Panthera onca mesembrina (large jaguar), the American Rhea (rhea large that persists in the north of Argentina), the Dusicyon avus (species of fox), coexisting with current species, such as Lama Guanicoe (guanaco), Dusicyon griseus (gray fox), Dusicyon culpaeus (red fox), Pterocnemia pennata (choique), Eudromia elegans (martineta) and Félix concolor (puma) (Miotti 2004; Paunero 2009a)."

*This image is copyright of its original author

"The María Bajo is also present, in this case with another variety of design, the animal, probably a jaguar, can be seen with negatives of close hands, seen from above, with the characteristic spots on its fur, its long tail and the vertebral column, as we can see in Figure 11. A unique and striking case, constitutes the large polychrome feline of cave 6B of El Ceibo, a ranch bordering The Mary, whose image we can see in Figure 12, this has a little more 1.50 m long, it is painted in red with the spots of its fur in black, it also has a bristling back and prominent claw-like legs. Cardich (1979) has interpreted this figure as corresponding to a species of large jaguar currently extinct, Panthera onca mesembrina, which inhabited the region more than 10,000 years ago. In this regard, it should be mentioned that in recent excavations carried out in the La María Quebrada Tunnel Cave, we have recorded a tooth of this species, associated with the buried evidence of the first colonizing human groups in the region." Reply