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  • New genetic evidence shows Miracinonyx trumani is more closely related to modern pumas than to African or Asian cheetahs.
  • The animal's slender build resulted from convergent evolution rather than direct ancestry with today's cheetahs.
  • Isotopic analysis indicates the species had a diverse diet, ranging from pronghorn in Wyoming to salmon in the Yukon.

A widely accepted classification of an extinct North American predator has been overturned by new genetic evidence. For decades, paleontologists identified Miracinonyx trumani as the American cheetah, assuming it was a close relative of the swift felines found in Africa and Asia today. However, a study published in Current Biology on September 4 demonstrates that the ancient cat was actually part of the puma lineage. This reclassification fundamentally alters the understanding of how large cats evolved across the continents during the Pleistocene epoch.

The research team analyzed four fossils discovered in Wyoming and Canada’s Yukon Territory. By extracting DNA from these remains, scientists constructed a detailed evolutionary tree that places M. trumani firmly within the New World lineage of pumas, also known as mountain lions or cougars. The genetic data indicates that this extinct species diverged from the ancestors of modern pumas approximately 2.6 million years ago. In contrast, its split from the cheetah lineage occurred much earlier, around 4.7 million years ago.

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The previous classification relied heavily on physical similarities between M. trumani and modern cheetahs. When the species was first described in 1979, researchers noted its elongated legs, slender build, and enlarged nasal cavities. These features suggested a lifestyle centered on high-speed pursuit hunting, similar to that of contemporary cheetahs. However, the new findings suggest these physical traits were not inherited from a common cheetah ancestor but evolved independently.

This phenomenon is known as convergent evolution, where unrelated or distantly related species develop similar characteristics due to comparable environmental pressures. Molly Cassatt-Johnstone, a molecular ecologist at the University of California, Santa Cruz and co-author of the study, noted that labeling the animal an American cheetah implied specific behavioral and ecological traits that may not have been accurate. The slender body shape was likely an adaptation for speed in open grasslands, mirroring the cheetah’s form without sharing its direct ancestry.

The discovery began with fossils found in the Yukon Territory, a region where American cheetahs had never previously been identified. Researchers initially assumed the remains belonged to pumas because of their northern location. It was only after generating genetic data that they realized the specimens were M. trumani. This identification prompted a broader analysis that included a fossil from Wyoming, allowing for a more comprehensive view of the species' range and habits.

Isotopic analysis of nitrogen and carbon in the fossils provided insights into the dietary flexibility of M. trumani. The specimen from Wyoming, dating back roughly 23,000 years, showed evidence of a diet rich in herbivores such as pronghorn. Conversely, the Yukon specimens, which are approximately 31,000 years old, indicated a significant consumption of fish, likely salmon. This dietary diversity highlights the animal's ability to adapt to different ecosystems across a vast geographic range.

The study also uncovered genetic adaptations related to climate and sensory perception. Researchers identified mutations that blocked certain genes regulating circadian rhythms, suggesting the animals adapted to the extreme light cycles experienced in northern latitudes during summer and winter. Additionally, all cat species included in the evolutionary tree, including lions and Canada lynx, lacked a functional gene for sour taste receptors. This mutation appears to have occurred millions of years ago, though it had not been previously noted in this context.

Ross Barnett, an independent paleontologist who led a 2005 study on the species but was not involved in the current research, emphasized the significance of finding these animals in Arctic biomes. The ability of M. trumani to thrive in such diverse environments, from temperate grasslands to northern forests, underscores its resilience. As a versatile predator, it likely occupied an ecological niche similar to that of modern pumas, which are known for their adaptability and wide distribution across the Americas.

This reclassification resolves long-standing questions about the migration and evolution of large cats in North America. Since pumas are native to the Americas while cheetahs are Old World species, a direct relationship would have required complex migration events that lacked supporting evidence. The new genetic data confirms that M. trumani was a distinct branch of the puma family tree, offering a clearer picture of prehistoric wildlife dynamics. Future research may further explore how these ancient predators interacted with other Pleistocene megafauna and how their extinction fits into broader climatic shifts.

The findings serve as a reminder that physical appearance can be misleading in evolutionary biology. While M. trumani looked like a cheetah, its genetic heritage tells a different story. By integrating ancient DNA with isotopic analysis, scientists have corrected a decades-old misconception and provided a more accurate narrative of North America’s prehistoric ecosystems. This work not only refines the taxonomy of extinct species but also enhances understanding of how animals adapt to changing environments over millions of years.

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  • Smithsonian Magazine↗For Decades, Scientists Thought an 'American Cheetah' Once Roamed North America. Turns Out the Extinct Cat Wasn't a Cheetah