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Description
Miracinonyx trumani
Cheetahs, a name that conjures up images of a magnificent and swift predator of the African savannah. Pursuing down gazelle, impala, and other swift mammals on the African Plains, these animals are among the fastest land vertebrates alive today. Estimates range between 55-80mph with 70mph being a commonly cited figure. However, the most accurately recorded speed is approximately 61mph. Whatever its top speed may be, this animal is an efficient specialist hunter of fast prey on the plains of Africa. However, some 13,000 years ago, another feline speedster dominated the plains of Ice Age North America, Miracinonyx trumani the American Cheetah.

History of Discovery:

This species that this profile is focusing on is Miracinonyx trumani, the American Cheetah. The type species is M. inexpectatus discovered by E.D. Cope. The species here, M. trumani was described by Phil Orr in 1969 as “Felis trumani”. The holotype specimen was a skull from the Crypt Cave in Nevada. It was named after former President Harry Truman. Orr noted that it was similar to the modern-day African Cheetah. A roughly triangular skull and wide nostrils, consistent with adaptations for running down prey. Some authors referred to the animal as “Acinonyx trumani” as being just an American cheetah.

A decade later, Daniel Adams described more material in a paper published in 1979. This was the dawn of the phylogenetic revolution that encompassed a lot of paleontology. In tandem with the new material and, he renamed the genus, dubbing the genus, Miracinonyx. The genus name is derived from the Greek meaning “Magnificent Immovable Claws”. A reference to the claws that couldn’t be retracted as is the case with the modern cheetah.

Taxonomy:

As previously discussed, the taxonomy and placement of the American cheetah was subject to confusion for many years. Some believed it was a true cheetah even after Miracinonyx was dubbed, others thought it was part of a broader genus of Cheetah or even a sister lineage to them. It wouldn’t be until 2016 when DNA of this animal was extracted, and it was found that this animal was not a true cheetah (in the genus Acinonyx) or a sister linneage.

It was found that this animal convergently evolved with the African cheetah and while closely related, the result of their evolution was the result of convergent evolution.

Roughly 3,000,000 years ago, the lineage of felines that would give rise to this animal was an animal that probably resembled the modern day Jaguarundi of South and Central America. Two different lines diverged, one would become the mountain lion, another line would become the American Cheetah. M. inexpectatus more or less resembled modern-day pumas but more lithely built. However, it still had features such as retractable claws and a more robust body compared to M. trumani. Filling the niche of not a cheetah, but more like a small leopard. The animal died out during the mid-Pleistocene some 1,000,000 years ago and in its place, its niche would be filled by animals such as the Jaguar, and its cousin, M. trumani, would shift its niche and become one of the fastest apex predators Pleistocene North America has ever seen.

Description:

Miracinonyx trumani was a lightly built felid, similar to its distant cousin, the cheetah. More or less, the animal would have resembled a cougar with cheetah-like proportions. Wider nasal passages, non-retractable claws and very long and lightly built limbs. The coloration or pattern of the animal is not known. It’s possible it could’ve been plainly colored like modern-day mountain lions, or it could have had some patterns designed to help it sneak up on prey. No cave paintings have been found associated to this animal nor have any mummified specimens have been found so the pattern is up to interpretation.

The animal was roughly 8.5-9ft long including the tail, 2.5ft tall and weighing in at around 140-160lbs. It was roughly on par if not slightly heavier than the modern cheetah. As for whether or not it was slower than the modern cheetah is not known, though this animal was definitely fast. Probably pursuing prey with very fast bursts of speed. For good reason.

Convergent Co-Evolution:

Modern day cheetahs run down lithely built animals like various species of gazelle and impalas. America has only one “antelope” species left today and that’s the pronghorn antelope. Despite its name, it's not a antelope or even a true bovine. Pronghorns are more closely related to giraffes and okapis than any antelope of the old world. They are part of the family Antilocapridae, and their body plan is a result of convergent evolution with antelopes. The pronghorn antelope of the American West is the only species of antilocaprid left. However, like most megafauna of America, their diversity was far greater with 4 genera existing in the Pleistocene.

Both the modern pronghorn and its extinct kin during the Pleistocene were swift animals. The pronghorn can reach speeds of 55mph today. Furthermore, it can sustain speeds for far longer than any other mammal. Smaller genera during the Pleistocene could have reached even faster speeds on the plains. Pronghorn limbs are highly specialized and have pretty much over-evolved muscles designed to reach extremely high speeds. Today, the only predators aside from humans that hunt them are mountain lions and wolves, both of which will either target a weak or injured individual or if there are perfect circumstances for them to bring them down. From a modern laymen’s perspective, it makes no sense. Why would such an animal evolve to run at high speeds if no modern predator can catch them reliably.

The only predator capable of hunting them reliably was Miracinonyx trumani. With its powerful fast bursts of speed, its believed that the high speed of pronghorn was the result of an evolutionary arms race between antilocaprids and Miracinonyx. If the predator-prey relationship was anything like the Serengeti, it’s not hard to imagine an adult M. trumani running down a pronghorn separating one from its group and then tackling it to the ground before strangulating it with its jaws.

Today, with its primary predators all but extinct, the pronghorn is equipped with the ability to outrun nearly all predators on the plains. An ability gifted to it from a predator now long gone.

Extinction:

The extinction of this fast felid is open to debate. Most paleontologists believe it was due to both climate change and human related factors. While pronghorn persisted past the quaternary extinction event some 10-11,000 years ago, other pronghorn did not. Its possible due to prey population decline, that contributed to it as well, however, as stated, it’s open to debate. One thing is known for sure. Some 12,000 years ago, the American cheetah vanishes from the fossil record.

Interestingly enough, genetic studies from the 2010s indicate that African cheetahs went through a population bottleneck resulting in varying degrees of inbreeding on par with some species of purebred dogs. How cheetahs survived is not known. Though what’s unfortunate is that cheetahs in Africa are at risk of extinction too. With only 7,000 individuals left in Africa, it’s far from certain if African cheetahs will escape to the same fate as their close cousins.
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Here's an animal I've been putting off for a while, but since today I have the day off from work, I thought I'd finally finish it. The pose here is inspired by PhilipEdwin 's marvelous American Cheetah he did almost a decade ago, thought I'd replicate it here. So, full credit to your amazing photo manipulation work.

Will this be in PMP? TBH, IDK at this point. It may be or may not. I can tell you firsthand, posing this guy is not an easy thing. Cheetah's running is an act in nature that's really hard to get good refs for. Still, I pulled as many pics as I could and I resulted in this pose here. Hope you guys like it!

American Cheetah by Tamara Henson:
American Cheetah (Dinosaur & Tamara Henson) | ZT2 Download Library Wiki | Fandom
Pronghorn by TycoonFan:
Pronghorn (Tycoonfan) | ZT2 Download Library Wiki | Fandom

Description
Miracinonyx trumani
Cheetahs, a name that conjures up images of a magnificent and swift predator of the African savannah. Pursuing down gazelle, impala, and other swift mammals on the African Plains, these animals are among the fastest land vertebrates alive today. Estimates range between 55-80mph with 70mph being a commonly cited figure. However, the most accurately recorded speed is approximately 61mph. Whatever its top speed may be, this animal is an efficient specialist hunter of fast prey on the plains of Africa. However, some 13,000 years ago, another feline speedster dominated the plains of Ice Age North America, Miracinonyx trumani the American Cheetah.

History of Discovery:

This species that this profile is focusing on is Miracinonyx trumani, the American Cheetah. The type species is M. inexpectatus discovered by E.D. Cope. The species here, M. trumani was described by Phil Orr in 1969 as “Felis trumani”. The holotype specimen was a skull from the Crypt Cave in Nevada. It was named after former President Harry Truman. Orr noted that it was similar to the modern-day African Cheetah. A roughly triangular skull and wide nostrils, consistent with adaptations for running down prey. Some authors referred to the animal as “Acinonyx trumani” as being just an American cheetah.

A decade later, Daniel Adams described more material in a paper published in 1979. This was the dawn of the phylogenetic revolution that encompassed a lot of paleontology. In tandem with the new material and, he renamed the genus, dubbing the genus, Miracinonyx. The genus name is derived from the Greek meaning “Magnificent Immovable Claws”. A reference to the claws that couldn’t be retracted as is the case with the modern cheetah.

Taxonomy:

As previously discussed, the taxonomy and placement of the American cheetah was subject to confusion for many years. Some believed it was a true cheetah even after Miracinonyx was dubbed, others thought it was part of a broader genus of Cheetah or even a sister lineage to them. It wouldn’t be until 2016 when DNA of this animal was extracted, and it was found that this animal was not a true cheetah (in the genus Acinonyx) or a sister linneage.

It was found that this animal convergently evolved with the African cheetah and while closely related, the result of their evolution was the result of convergent evolution.

Roughly 3,000,000 years ago, the lineage of felines that would give rise to this animal was an animal that probably resembled the modern day Jaguarundi of South and Central America. Two different lines diverged, one would become the mountain lion, another line would become the American Cheetah. M. inexpectatus more or less resembled modern-day pumas but more lithely built. However, it still had features such as retractable claws and a more robust body compared to M. trumani. Filling the niche of not a cheetah, but more like a small leopard. The animal died out during the mid-Pleistocene some 1,000,000 years ago and in its place, its niche would be filled by animals such as the Jaguar, and its cousin, M. trumani, would shift its niche and become one of the fastest apex predators Pleistocene North America has ever seen.

Description:

Miracinonyx trumani was a lightly built felid, similar to its distant cousin, the cheetah. More or less, the animal would have resembled a cougar with cheetah-like proportions. Wider nasal passages, non-retractable claws and very long and lightly built limbs. The coloration or pattern of the animal is not known. It’s possible it could’ve been plainly colored like modern-day mountain lions, or it could have had some patterns designed to help it sneak up on prey. No cave paintings have been found associated to this animal nor have any mummified specimens have been found so the pattern is up to interpretation.

The animal was roughly 8.5-9ft long including the tail, 2.5ft tall and weighing in at around 140-160lbs. It was roughly on par if not slightly heavier than the modern cheetah. As for whether or not it was slower than the modern cheetah is not known, though this animal was definitely fast. Probably pursuing prey with very fast bursts of speed. For good reason.

Convergent Co-Evolution:

Modern day cheetahs run down lithely built animals like various species of gazelle and impalas. America has only one “antelope” species left today and that’s the pronghorn antelope. Despite its name, it's not a antelope or even a true bovine. Pronghorns are more closely related to giraffes and okapis than any antelope of the old world. They are part of the family Antilocapridae, and their body plan is a result of convergent evolution with antelopes. The pronghorn antelope of the American West is the only species of antilocaprid left. However, like most megafauna of America, their diversity was far greater with 4 genera existing in the Pleistocene.

Both the modern pronghorn and its extinct kin during the Pleistocene were swift animals. The pronghorn can reach speeds of 55mph today. Furthermore, it can sustain speeds for far longer than any other mammal. Smaller genera during the Pleistocene could have reached even faster speeds on the plains. Pronghorn limbs are highly specialized and have pretty much over-evolved muscles designed to reach extremely high speeds. Today, the only predators aside from humans that hunt them are mountain lions and wolves, both of which will either target a weak or injured individual or if there are perfect circumstances for them to bring them down. From a modern laymen’s perspective, it makes no sense. Why would such an animal evolve to run at high speeds if no modern predator can catch them reliably.

The only predator capable of hunting them reliably was Miracinonyx trumani. With its powerful fast bursts of speed, its believed that the high speed of pronghorn was the result of an evolutionary arms race between antilocaprids and Miracinonyx. If the predator-prey relationship was anything like the Serengeti, it’s not hard to imagine an adult M. trumani running down a pronghorn separating one from its group and then tackling it to the ground before strangulating it with its jaws.

Today, with its primary predators all but extinct, the pronghorn is equipped with the ability to outrun nearly all predators on the plains. An ability gifted to it from a predator now long gone.

Extinction:

The extinction of this fast felid is open to debate. Most paleontologists believe it was due to both climate change and human related factors. While pronghorn persisted past the quaternary extinction event some 10-11,000 years ago, other pronghorn did not. Its possible due to prey population decline, that contributed to it as well, however, as stated, it’s open to debate. One thing is known for sure. Some 12,000 years ago, the American cheetah vanishes from the fossil record.

Interestingly enough, genetic studies from the 2010s indicate that African cheetahs went through a population bottleneck resulting in varying degrees of inbreeding on par with some species of purebred dogs. How cheetahs survived is not known. Though what’s unfortunate is that cheetahs in Africa are at risk of extinction too. With only 7,000 individuals left in Africa, it’s far from certain if African cheetahs will escape to the same fate as their close cousins.
___________________________________________________________________________________________

Here's an animal I've been putting off for a while, but since today I have the day off from work, I thought I'd finally finish it. The pose here is inspired by PhilipEdwin 's marvelous American Cheetah he did almost a decade ago, thought I'd replicate it here. So, full credit to your amazing photo manipulation work.

Will this be in PMP? TBH, IDK at this point. It may be or may not. I can tell you firsthand, posing this guy is not an easy thing. Cheetah's running is an act in nature that's really hard to get good refs for. Still, I pulled as many pics as I could and I resulted in this pose here. Hope you guys like it!

American Cheetah by Tamara Henson:
American Cheetah (Dinosaur & Tamara Henson) | ZT2 Download Library Wiki | Fandom
Pronghorn by TycoonFan:
Pronghorn (Tycoonfan) | ZT2 Download Library Wiki | Fandom