(CN) — After over a decade of research and hundreds of new fossils recovered from the hot mines of India, researchers say they have uncovered new details regarding the evolutionary history of Earth’s most famous hoofed animals.
For centuries, scientists have labored to construct comprehensive records that detail how Earth’s many creatures have evolved and adapted. Perhaps one of the most explored animal groups are perissodactyls, a specific group of hoofed animals that includes horses, zebras and even rhinoceroses that have played crucial roles in societies and cultures around the world for centuries.
Despite being on researchers’ radar for so long, questions have long swirled over some key details in the evolutionary backstory of perissodactyls, perhaps most notably where on Earth they evolved in the first place.
In a study published Friday in the Journal of Vertebrate Paleontology, experts say that they may have answered some of these pressing questions after an exhaustive research effort that stretches back 15 years.
Friday’s study reports that researchers have amassed data from more than 350 new fossils to create a virtually complete profile of the skeletal makeup of the cambaytherium, a long extinct sheep-like animal that researchers say is an evolutionary cousin of perissodactyls.
After analyzing cambaytherium bones and comparing them with other mammals, both living and extinct, researchers concluded the cambaytherium represents one of the earliest and most primitive stages for any known perissodactyl.
With the fossil record suggesting that cambaytherium lived on the Indian subcontinent roughly 55 million years ago before eventually dispersing to other parts of the world, this area likely served as the earliest known evolutionary home for perissodactyls as well.
Ken Rose, emeritus professor at Johns Hopkins University and lead author of the study, said that given what researchers were able to uncover about the cambaytherium and how closely they connect with perissodactyls, experts now have a much more comprehensive understanding of perissodactyls and their earliest ancestors.
“You can think of a sister-group as a cousin to perissodactyls; the fossil evidence suggests that both perissodactyls and cambaytherium shared a common ancestor, i.e., they had the same grandpa,” Rose said in an email. “Cambaytherium, while showing evidence of relationship to perissodactyls, retains more primitive features (grandpa’s features) than do perissodactyls, so it gives us a clearer picture of what the ancestor of perissodactyls was like.”
While the cambaytherium was first revealed in 2005 and it became clear that they branched off on their own prior to the evolution of perissodactyls as they’re know today, researchers say it has taken years to fully explore their hypothesis that perissodactyls first evolved in India where cambaytherium thrived millions of years ago.
Researchers say they had to make several expeditions to India in their hunt for rare fossils throughout the years before eventually coming across the Vastan Mine in Gujarat. At this active open-pit lignite mine, researchers worked through hot and dusty conditions to at last collect enough fossils to support their theory.
Rose says he is optimistic that this new and critical information, gathered after more than a decade’s worth of challenging fieldwork and examination of hundreds of prehistoric fossils, will significantly shakeup the ongoing research into perissodactyls and help to answer more questions regarding this well-debated order of animals.
“I hope these two main conclusions — adding two new pieces to the puzzle — will stimulate a lively discussion/debate among paleontologists about the origin of the order Perissodactyla,” Rose said.
Read the Top 8
Sign up for the Top 8, a roundup of the day's top stories delivered directly to your inbox Monday through Friday.