Ancient Jaguars

[Balam]

(06-19-2020, 07:09 AM)Richardrli Wrote: A few questions from me

1) How can we be so sure that mesembrina was actually larger than augusta? Any specific measurements of bones/skulls to compare? I have no agenda, just curious

2) What's the current situation regarding the confusion of these Pleistocene jaguars with Panthera atrox? Especially in South America how many of these speculative mesembrina remains are possibly/likely to be Atrox? Again no agenda, just want to know

3) Where exactly did the jaguar species originate? In Europe or somewhere in Asia?

These are good questions! First off, the initial post from this thread discusses the morphological differences between mesembrina and augusta and the researchers estimated their weights based off the skull and overall skeleton measurements they gathered from both subspecies using a formula (the formula is posted above). It's worth pointing that the fossils themselves are stated in the article to be unpublished so we don't have access to them, only they have. The entire article is this one and they go into more detail about the specifics of the equations used to determine body mass for both species as well as their prey items: https://www.sciencedirect.com/science/ar...8317301094

Also, colleague @epaiva had shared with us before this claim of maximum weight for augusta in the edge of extinction thread from a different source:

*This image is copyright of its original author

Notice that the difference between that estimation and the one gathered from the article is 20 kg, 190 to 210 kg. So regardless of the data used, augusta appears to present constant lower values than mesembrina.

Your second question is also touched upon in the article. The researches claim that the other Patagonia fossil remains could be confidently be inferred as belonging to atrox due to skulls and some other biological traces such as a claw and fur that present similarities with atrox remains in North America. This doesn't disprove the previously stated size calculations for mesembrina since it is coming from the same paper, especially since they described skull differences between atrox and mesembrina in detail to sustain why they made the claims that such remains belonged to the lion and not the jaguar.

Finally, jaguars most likely originated in Central Asia from a clade of African pantherines from whom leopards and lions also had their roots, then spread to Europe and eventually reached the Americas. I will be covering the European jaguar and jaguar evolution more in-depth in future posts. Reply