Jaguar vs Epicyon

[Runic]

No, you still don't get it.

No, it is you who doesn't understand.

It doesn't matter how many terms you put between them

YES IT DOES! This just showed you have no idea what you are talking about. 

if A is part of B which is part of C, A is also part of the C thing.

No A is part of B which is then a part of C

The ability to accellerate quickly is much more relevant here than top speed is,

Incorrect

so no matter what definitions you juggle, it remains that way.

Incorrect.

[theropod]

So, I guess humans (A) can impossibly be mammals (C), can they? They are after all, primates (B), which are mammals (C), so humans are only primates, no mammals, by what you just wrote.

For the "ability to change your bodies position", how quickly you can accellerate is of great importance. The quicker, the better.

Top speed on the other hand only plays a role if the body actually gets to be accellerated long enough to attain it, which would only happen in a race or a chase.

[Infinity Blade]

This is a very cool fight IMO. The Epicyon is a canid that can actually grapple with its forelimbs, and the only thing that it doesn't have that the jaguar does in that regard is retractile claws. I really don't believe this is going to be an overly huge issue, so when both are grappling/wrestling with each other, it'll come down to their jaws. Bite force is both animals' things and the borophagine most likely has the stronger bite, so I think I'd give it the edge.

[Infinity Blade]

Would anyone else like to express their opinion on this fight?

[Runic]

Epicyon imo.

[Vodmeister]

Can you specify this thread to Pantanal Jaguar? Otherwise the Epicyon has too much of a size advantage.

At equal weights this is one of the ultimate 50/50 fights IMO.

[Infinity Blade]

Looks like there already is a topic for this.

theworldofanimals.proboards.com/thread/414/jaguar-epicyon

[creature386]

I did my job.

[Vodmeister]

Epicyon was nowhere near as large as previously thought. According to blaze on CF, it only averaged about 160 pounds and maxed out at 216 pounds.

In which case, the Jag wins pretty convincingly.

[malikc6]

I think the big cat takes this. The jaguar has claws, better equipped forearms, and is heavier.

[blaze]

I'll repurpose my comment from cf.

The size of Epicyon haydeni is often exaggerated, a common figure you find on the internet is that large specimens weighted 170kg (375lbs), it comes from Sorkin (2008) and is a simple isometric scaling based on the largest E haydeni humerus and the humerus and weight of spotted hyena taken from the literature but, how accurate it really is?

To put its size in perspective we can compare the length of its skull, according to Munthe (1989), the average for the sample from the Port of Entry Pit (n=7) is 304mm, one centimeter longer than the skull of the dire wolf from Rancho La Brea, the "60kg" population. Munthe (1989) also provides limb measurements, which we can use to estimate body mass.

Measurements of Epicyon haydeni humeri.

Specimen	HL	HDW	HDAW
F:AM 67602	290	75	47.5
F:AM 67601	284	73.5	45.5
F:AM 67665	219	55	35.5

HL=humeral length
HDW=humeral distal width
HDAW=humeral distal articular width

Equations used

Source	Equation	R2	%PE	Notes
Christiansen (1999)	BM = 0.000009*HL2.881	0.977	28	All carnivora
Christiansen (1999)	BM = 0.002*HDW2.511	0.978	32	All carnivora
Figueridio et al. (2011)	logBM = 3.366*logHL - 6.215	0.978	22.4	Canidae+Ursidae
Figueridio et al. (2011)	logBM = 2.187*logHDW - 2.108	0.989	18	Canidae+Ursidae
Figueridio et al. (2011)	logBM = 2.276*logHDAW - 1.946	0.991	14.9	Canidae+Ursidae
Original	logBM = 2.8885*logHL - 5.2383	0.932	3.6	Canidae

Note: The equation labeled "original" I made it with the data from the supplemetal of Campione and Evans (2012)

Estimated mass of Epicyon haydeni

Specimen	C1999.HL	C1999.HDW	F2011.HL	F2011.HDW	F2011.HDAW	Original.HL	Mean
F:AM 67602	112	102	118	98	74	75	97
F:AM 67601	105	97	110	94	67	71	91
F:AM 67665	50	47	46	50	38	33	44

The smallest humerus comes from Port of Entry Pit while the larger two come from the Jack Swayze quarry, this quarry only turned up big specimens, averaging 15% larger than the those from Port of Entry Pit and other localities based on dental measurements but comparable to the larger specimens of those same localities (Baskin, 1998), whatever the two larger humeri represent average or large individuals in the context of that specific locality I don't know but they definitely are the largest Epicyon humeri known.

Regarding its robustness and grappling ability, this is what Munthe (1989) says:

The slenderer skeletons of Epicyon saevus and E. haydeni compared to those of the Aelurodon group, indicates that the former were more cursorial, possible capable of longer-distance travel. E. validus (junior synonym of E. haydeni), however, was quite a heavy animal; no living carnivore of that size is capable of long-distance running. Osteoborus (junior synonym of Borophagus) and Borophagus were possibly the least cursorial of the larger borophaghines. Their limbs in some cases are even more robust than those of E. validus, and aspects of their skeletons indicate a greater freedom of movement at the major limb joints than in other taxa. [...]

Comparisons between the forelimbs of borophagines and the extant carnivores discussed above show that, while possessing some modifications for cursorial locomotion, the borophagine forelimb, and particularly the antebrachium, was capable of a greater range of movement than is possible in living canids and hyaenids. It's versatility, however, was probably not as great as in felids.

Other things that diminish their grappling ability compared to cats according to Munthe (1989) are their blunt non-retractable claws and their relatively small paws with more appressed (pressed closely together) digits.

[Infinity Blade]

Palmqvist et al. (2016)

Here, we perform an ecomorphological study on the major bones (humerus, radius, and ulna) of the carnivoran forelimb using three-dimensional geometric morphometrics. More specifically, we test the association between forelimb morphology and predatory behavior. Our results suggest that the main morphological adaptions of carnivorans to different predatory behaviors relate to: (i) the capacity to perform long and efficient runs as in pounce/pursuit and pursuit predators; (ii) the ability to maneuver as in occasional predators; and (iii) the capacity to exert and resist large loads as in ambushing predators. We used borophagine canids as a case study, given the controversy on the predatory behavior of this extinct subfamily. Our results indicate that borophagines displayed a limited set of adaptions towards efficient running, including reduced joint mobility in both the elbow and the wrist, aspects in which they resemble the living canids. Furthermore, they had forelimbs as powerful as those of the extant ambushing carnivorans (i.e., most felids). This combination of traits suggests that the predatory behavior of borophagines was unique among carnivorans, as it was not fully equivalent to any of the living species.

For example, those species with a straight shaft and a long olecranon process (e.g., A. ferox; Fig. 3c, d) have a high mechanical advantage for the triceps brachii and the ability to develop a more flexed posture. This indicates that they could have used their forelimbs to some extent to grapple with prey. In contrast, those species with a curved shaft and a more upright posture (e.g., A. taxoides, E. saevus, and E. haydeni; Fig. 3c, d) were not clearly adapted to grapple with prey. In contrast, they could have developed a more efficient locomotion (e.g., A. taxoides and E. haydeni; Fig. 3e, f), although there is always the possibility that they were not secondarily adapted to grapple with prey if a cursorial condition was basal to these groups (e.g., E. saevus; Fig. 3e, f).

Sorkin (2008)

In fact, the humeri of Epicyon, Homotherium, and the living Hyaenidae were as robust as those of most felids (Fig. 5), but the deltoid ridges of Epicyon and the living Hyaenidae (represented by the spotted hyena) were significantly shorter than those of the Felidae (Fig. 6).

Among terrestrial mammalian predators with humeri of similar robustness (Epicyon, Hyaenidae, ‘Felinae’, and Amphicyoninae), the lineage with the relatively longest deltoid ridge/deltopectoral crest (Amphicyoninae) attained the greatest maximal body mass, greater even than those of the lineages with the more robust humeri, but shorter deltoid ridges (Smilodon and Panthera spelaea/atrox).

It seems that there wasn't just increased flexibility (relative to the forelimbs of modern canids) that made borophagine forelimbs more useful for prey acquisition. They were just as powerful as those of modern felids (their humeri in particular were comparable in robustness)! Granted they were still inferior at grappling than the arms of big cats due to their lack of raptorial claws, and Epicyon haydeni was leaning more towards cursorial locomotion than some other borophagines. But the fact that their forelimbs were apparently just as powerful is surprising. In addition to some extent of grappling ability, it's been proposed that borophagines could still have hit their prey and knock them down during a chase, like what brown bears do when hunting ungulates (Van Valkenburgh et al., 2003).

I wonder if this is why borophagines were (putatively) outcompeted by canines and felids (and to a lesser extent, barbourofelids). Felids and barbourofelids were superior grapplers than borophagines were, so these canids faced competition more formidable than they were in this regard. They were more developed cursors than the grappling carnivorans, so theoretically competition with cats and barbourofelids could have selected for individuals better adapted for running and eventually resulted in even more cursorial borophagines. There was just one problem: the canines were there too, and they were better cursors than the borophagines. Coexisting with better grapplers and better runners, they would have had nowhere to turn ecologically speaking.

It may be worth noting that in 2015, another study independently estimated two different specimens of Epicyon haydeni to weigh well over 100 kg (one at 139.7 kg and the other at 175.7 kg). Even the smallest individual in that study still weighed 92.9 kg. These estimates seem to be based on elbow centroid size (Figueirido et al., 2015).

References:

- Figueirido, B., Martín-Serra, A., Tseng, Z. et al. Habitat changes and changing predatory habits in North American fossil canids. Nat Commun 6, 7976 (2015). doi.org/10.1038/ncomms897

- Palmqvist, P.; Martín-Serra, A; Figueirido, B. In the Pursuit of the Predatory Behavior of Borophagines (Mammalia, Carnivora, Canidae): Inferences from Forelimb Morphology. Journal of Mammalian Evolution. DOI: 10.1007/s10914-016-9321-5

- Silvestro, D; Antonelli, A; Salamin, N; Quental, T.B. The role of clade competition in the diversification of North American canids. Proceedings of the National Academy of Sciences of the United States of America. DOI: 10.1073/pnas.1502803112

- Sorkin, B. (2008). A biomechanical constraint on body mass in terrestrial mammalian predators. Lethaia, 41(4), 333-347.

- VAN VALKENBURGH, B. L. A. I. R. E., SACCO, T., & WANG, X. (2003). Chapter 7: Pack hunting in Miocene Borophagine dogs: evidence from craniodental morphology and body size. Bulletin of the American Museum of Natural History, 147-162.

[jhg]

The 'epic dog' wins after getting its face badly rearranged. It's an epic match.

[Deleted]

Indeed it is, and I back the latter.

[dinosauria101]

Jaguar wins this easily. Epicyon's been downsized