An incredible Fossil with an even more incredible story.
Millions
of years before members of the cat family (felidae) evolved 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.
Seth Sorensen
President/CEO
Fossil Shack
www.fossilshack.com
