Panthera atrox--a giant jaguar?

[ambulocetus]

I read recently that panthera atrox, or the North American "cave lion", was actually a giant jaguar. Is there anything definitive on this, or is the jury still out? one recent aquistion to my collection is the La Brea bronze version. It actually looks more like a European cave lion, as it lacks an actual mane. P. atrox was assumed to have mane in hunt in prides like African lions today, only much larger.

[sbell]

May 22, 2011 3:01:11 GMT ambulocetus said:

I read recently that panthera atrox, or the North American "cave lion", was actually a giant jaguar. Is there anything definitive on this, or is the jury still out? one recent aquistion to my collection is the La Brea bronze version. It actually looks more like a European cave lion, as it lacks an actual mane. P. atrox was assumed to have mane in hunt in prides like African lions today, only much larger.

There is no evidence for a mane--just as there is no evidence for pride hunting (an aberrant cat behaviour to say the least). The word "lion" just automatically assumes a mane and prides are involved. The same goes for animals like Smilodon; we can't say they didn't (manes or prides) but parsimony means it is unlikely.

But yes, P.atrox is assumed to be a large relative of P.onca now.

[Horridus]

Abstract from "Craniomandibular Morphology and Phylogenetic Affinities of Panthera atrox: Implications for the Evolution and Paleobiology of the Lion Lineage" - Per Christiansen & John M. Harris

"The great North American Pleistocene pantherine felid Panthera atrox has had a turbulent phylogenetic history, and has been claimed to show affinities to both the jaguar and the tiger; currently, it is most often regarded as a subspecies of the extant lion. The cranial, mandibular, and dental morphology of Panthera atrox was compared with those of extant lions, jaguars, and tigers using bivariate, multivariate, and shape analyses. Results indicate that the skull of Panthera atrox shows lion affinities, but also deviates from lions in numerous aspects. Mandibular morphology is more similar to jaguars and tigers and, as with cranial morphology, the mandible shows a number of traits not present among extant pantherines. Multivariate analyses grouped Panthera atrox separately from other pantherines. Panthera atrox was no lion, and cannot be assigned to any of the extant pantherines; it constituted a separate species. A possible scenario for evolution of P. atrox is that it formed part of a pantherine lineage that entered the Americas in the mid-Pleistocene and gave rise to the extant jaguar and Panthera atrox in the late Pleistocene of North America. These studies suggest that previous models of lion biogeography are incorrect, and although lions may have been present in Beringia, they did not penetrate into the American mainland."

www.bioone.org/doi/abs/10.1671/039.029.0314

It's still generally classified as a subspecies of Panthera leo though, right? (I have no idea, I've been reading about this in the last 10 minutes or so - it's interesting!)

[sbell]

May 22, 2011 19:15:31 GMT Horridus said:

Abstract from "Craniomandibular Morphology and Phylogenetic Affinities of Panthera atrox: Implications for the Evolution and Paleobiology of the Lion Lineage" - Per Christiansen & John M. Harris

"The great North American Pleistocene pantherine felid Panthera atrox has had a turbulent phylogenetic history, and has been claimed to show affinities to both the jaguar and the tiger; currently, it is most often regarded as a subspecies of the extant lion. The cranial, mandibular, and dental morphology of Panthera atrox was compared with those of extant lions, jaguars, and tigers using bivariate, multivariate, and shape analyses. Results indicate that the skull of Panthera atrox shows lion affinities, but also deviates from lions in numerous aspects. Mandibular morphology is more similar to jaguars and tigers and, as with cranial morphology, the mandible shows a number of traits not present among extant pantherines. Multivariate analyses grouped Panthera atrox separately from other pantherines. Panthera atrox was no lion, and cannot be assigned to any of the extant pantherines; it constituted a separate species. A possible scenario for evolution of P. atrox is that it formed part of a pantherine lineage that entered the Americas in the mid-Pleistocene and gave rise to the extant jaguar and Panthera atrox in the late Pleistocene of North America. These studies suggest that previous models of lion biogeography are incorrect, and although lions may have been present in Beringia, they did not penetrate into the American mainland."

www.bioone.org/doi/abs/10.1671/039.029.0314

It's still generally classified as a subspecies of Panthera leo though, right? (I have no idea, I've been reading about this in the last 10 minutes or so - it's interesting!)

Given that they keep referring it to Panthera atrox, and not P. leo atrox, that should give a bit of a clue!

[Horridus]

But...Wikipedia cannot be lying to me! en.wikipedia.org/wiki/American_Lion

Weirdly, there's some discussion about how to classify it on the talk page, and they reached the conclusion that it should be Panthera atrox, as you say. And yet - the article still presents the animal as Panthera leo atrox.

[eriorguez]

I'm just going to drop this: A GENETIC study showed it to be closer to P.leo that to P.onca. You cannot try to use a MORPHOLOGICAL study to counter that. Tenrecs are closer to elephants that to hedgehogs, despite all morphological evidency to the contrary.

I'd separate P.atrox from leo and onca; I'd even keep P.speala separated, and I'm a lumper. Also, P.uncia, not Uncia uncia. Closest relative of P.tigris, and we aren't taking the tiger out of the genus, because it is the ****ing tiger. XD

[dinoguy2]

May 30, 2011 8:52:35 GMT eriorguez said:

I'm just going to drop this: A GENETIC study showed it to be closer to P.leo that to P.onca. You cannot try to use a MORPHOLOGICAL study to counter that.

Plenty of people would argue with you on that one. Genetic studies can and have produced some very weird results, and there are flaws in reconstructing phylogeny based on genetics just as there are with morphological phylogenies.

I don't know about this particular study, but I'd caution that many genetic studies in the past have made some pretty big assumptions, like assuming a standard rate of mutation, that are simply unsupportable and completely pollute the results.

dml.cmnh.org/2006Jan/msg00611.html

Do you have a reference for the genetic study? I'm curious about its sample size, etc.

The other thing to remember about phylogeny, is that it's relative what we mean by "close." P. atrox could be closer to P. onca than to P. leo in a phylogenetic sense (i.e. part of the clade onca > leo rather than onca < leo), but if it's at or near the base of that branch, it would still be genetically closer to P. leo. That is to say, if jaguars evolved from a lion-like ancestor, P. atrox might be close to that ancestor and have diverged after the lion/jaguar split occurred. So while it was still extremely lion like in appearance and genetics, it is still technically part of the jaguar clade, though a very primitive, and still very lion-like member. Jaguars would since have diverged even farther, and their genes with them.

I'll try to put this in a dinosaur sense... Coelurus is one of the most primitive coelurosaurs, but we know it IS a coelurosaur--that is, it's more closely related to birds than to Allosaurus. If we tested it's genes against those of a pigeon and those of an Allosaurus, however, it would certainly be *genetically* closer to an Allosaurus, despite being part of the bird group in terms of actual relationships.

[eriorguez]

You got me there. I would argue in the favor of comparing secuences with very low mutational rates (IIRC some cytochrome coding region was the one of choice for this), and using molecular clocks to verify it...

Still, Pantherinae taxonomy, even with extant species only, is still a mess (the only thing we are quite sure about is that Neofelis is basal), so I won't try to go on and touch it without any insight.