Oldie But Goodie

[sseth]

I would like to share my new fossil. It is one that truly tells a story and fills in missing pieces of information in the history of the evolution of Ancient Cat-like animals. The fossil itself is rare, but it possesses many features that help us understand these amazing animals.

Pogonodon Platycopis

A long time ago in a galex… I guess that really doesn’t work here. It is much closer to home.

Millions of years before members of the cat family (felidae) evolve into the famous saber-tooths, a primitive group of carnivores, now extinct, had already adapted themselves to this specialized niche. These were the Nimravids, which diversified into many of the specializations we see in living felids. In addition to developing a saber-toothed morphology, Nimravids had invaded the predatory niches occupied by todays Bobcats, Leopards, Lions, and Cheetahs.

Based on fossils dating from the Eocene of North America, approximately 40 million years ago, the Nimravids had already acquired many of the diagnostic features of the feline family. These ancestral species had already developed small chin flanges, small lower canines, reduced dentition and many other incipient characteristics associated with smilodonty (could be a made-up word).

The Oligocene provided ideal conditions to develop and perfect forms such as Dinictis, Hoplophoneus, Nimravus, Dinaelurus and Pogonodon. They evolved, survived, and flourished. During most of the Oligocene Epoch, Dinictis species were widespread and diverse, and ranged in size from a Bobcat to a Leopard. Near the end of the epoch, certain populations of Dinictis gave rise to extreme hyper-developed forms. One of them was Pogonodon, which evolved into a top super-predator.

The decline of hyaenodonts during that time may have allowed species of Pogonodon to evolve into a larger, more dominant, saber toothed type of carnivore.

The current fossil record indicates that the evolutionary history of Pogonodon is restricted to the Late Oligocene of North America.

Features of this skull also indicate that like modern lions, Pogonodon may have lived in groups or prides consisting of many individuals who hunted and fed together. This skull of a very old individual has teeth, which in many cases, are worn down to nothing more than nubs. The condition of these teeth would have made it very difficult for the animal to have hunted and killed other creatures and suggest that it may have just participated in group feedings after the hunt.

Unlike most animals, the upper teeth of Pogonodon have an inward curve and continued their growth until the animal died, or the teeth fell out. The lower teeth had an outward curve, causing them to constantly rub against the top teeth, creating an efficient way to keep the teeth sharp over the animal’s lifetime. These features are visible clearly in the teeth of this animal. The teeth have been worn down past the enamel and the molars are still sharp. One tooth has been exposed to the root, and the curve can be plainly seen. At one point, this was believed to only be a feature present in hyaenodonts.

This Pogonodon skull also sports a distinctive canine that was broken off at some point in life, and then used and worn down extensively to gain a polished and rounded tip. The skull is also mussing a number of teeth that were lost during life and the bone in the law has partially or completely filled in the root spacing. This indicates that this was indeed a very old animal indeed.

It took me some time to acquire and authenticate this skull, but I had suspicions for quite some time.

Edited December 16, 2014 by sseth

[sseth]

Here is the skull compared to a fairly large Hoplophoneus.

[sseth]

Here is another worn tooth picture showing the curve of the tooth and the lack of enamel

[jpc]

I would agree that this guy survived nicely despite having worn teeth, but I might add a separate theory. Maybe he changed his behavior. My inspiration for this is the fact that Swainson's hawks have been known to survive quite well in the wilds thank you, with broken wings. They have been shown to take to an active running carnivory method of hunting. Changed his behavior form what to what, I venture not a guess.

Oh, um, yeah... nice fossil.

[Auspex]

Thanks for the wonderful species account! This fantastic specimen tells a real story.

[Triceratops]

An amazing fossil and a great story to go with it!

Edited December 15, 2014 by Triceratops