It was a prehistoric jigsaw puzzle that had stumped paleontologists at the University of Alberta for close to 30 years.
For years, researchers at the Edmonton-based university kept finding tall, sharply pointed teeth - some the shape of an hourglass - and jaw fragments along the banks of the Blindman River in central Alberta. But the small, 60-million-year-old fossils, which were found by meticulously picking through shale and sandstone, didn't seem to belong to any known extinct mammals.
But tooth by tooth, the ancient puzzle slowly started to come together, and the Alberta scientists were eventually able to provide the first and only account of a small extinct creature they've dubbed Horolodectes sunae. Their findings were recently published in the Journal of Paleontology.
"In an area of North America that's been fairly well studied, it's unusual to have a new critter pop up," said Craig Scott, a University of Alberta PhD student and lead author of the study. "It's not known anywhere else, just in Alberta. And it's quite distinct."
He said the mystery took so long to solve because the mammal's upper and lower teeth were never found together, "so they weren't recognized as belonging to the same thing."
Horolodectes sunae, which ate mainly insects and grubs, was likely a furry creature about the size of a hedgehog (between 10 to 15 centimetres long).
However, it's difficult to describe exactly what it looked like because researchers have not yet recovered a complete skeleton. In Greek, Horolodectes means "hourglass biter."
The animal wandered in what is now modern Alberta during the Paleocene epoch, the 10 million years after the extinction of dinosaurs when mammals emerged as the planet's dominant animal, before eventually hitting an "evolutionary dead-end" during that same period, according to Mr. Scott.
"Alberta is known for its dinosaurs, and rightly so. But there were a lot of other things that were living at the time of the dinosaurs and after the dinosaurs that you don't hear so much about," he added.
Richard Fox, a renowned vertebrae paleontologist at the university, who worked on the study from the beginning, said it was sparked by an accidental discovery by an amateur paleontologist in 1977.
He said a University of Alberta genetics professor was actually hunting for insect fossils when he stumbled across some of the prehistoric teeth, which helped sparked the long-standing mystery.
"I'm 73 years old and I still get a charge out of these kinds of things," said Prof. Fox, who is professor emeritus of biological sciences at the University of Alberta, about the discovery of the previously undocumented extinct mammal.
He said fossils are abundant in the province's Blindman River region, which meanders through farmland in central Alberta, and will likely yield even more undocumented species in the future.
Mr. Scott said that while the discovery of Ho rolodectes sunae is "a window into the natural history" of Alberta, more works need to be done on this mysterious creature because other body parts haven't yet been found.
Until that happens, more information about the ancient mammal remains an "open question."