Fossilized turtle found in Sask. a rare specimen, researchers say
A 66 million-year-old turtle discovered in Saskatchewan has researchers at the Royal Saskatchewan Museum (RSM) excited, as it is one of only two fossil specimens of its kind ever studied in North America.
The uniquely intact fossil has been identified as a new species of soft-shelled turtle, included in the same genus as the modern-day mud turtle.
Researchers named it Leiochelys tokaryki, or Tokaryk's smooth turtle, in recognition of former RSM curator Tim Tokaryk and his extensive contributions on Cretaceous-period fossils in the province.
“Tim Tokaryk put a good portion of his career into developing dinosaur and marine reptile paleontology in Saskatchewan, so it's great to see him recognized,” RSM paleontology curator Dr. Ryan McKellar said.
The turtle was found in 2016 during the excavation of a Triceratops near Grasslands National Park. The tiny creature was tucked underneath one of the larger dinosaur's limb bones when the dig crew found it.
“We started digging fairly carefully around the shell (and) bundled it all up in a very small package to bring back to the lab,” Mckellar said.
About the size of a fist, the small fossil is a very rare example, McKellar said. All of its bones are preserved cleanly within the shell, as well as the skull.
“The bones that make up the shell are very, very thin, with the shell itself only two or three millimetres thick,” Mckellar said.
The only other specimen in this condition came from Mexico, he added. Field work in Saskatchewan and Alberta has yielded fragments of shells, but rarely a specimen this complete.
The nature of the species means that most deposits are located in what used to be river channels, which means remains are often “disarticulated, scattered skeletons.”
“We find one or two partial shells each year in the fields, usually even a half or third or quarter if we're lucky,” Mckellar said. “So this is very special for the collection, and for paleontology on the whole.”
Paleontologists also have a hard time making a detailed identification with only fragments of shells available.
“The shells don't have much in the way of external texture, so we may know they are soft-shelled turtles but (not much) beyond that,” Mckellar said.
The team of researchers involved in looking at the exciting fossil, including Mckellar and University of Regina graduate student Caelan Libke, have only recently published their discovery.
The two worked closely with Alberta's Royal Tyrrell Museum curator emeritus Don Brinkman and Canadian Light Source synchrotron scientist Dr. Sergei Gasilov in Saskatoon in examining and identifying the specimen as a new species.
Scans of the delicate bones and shell were done using the synchrotron, which was monumental as it allowed a “deep dive” look at the bone features that otherwise would not have been possible.
It's also a burgeoning technique within the field of paleontology, Libke said, and one that he and Mckellar are pushing to use more.
“Synchrotrons in other areas of the world have been used to study the skulls of turtles, but I think this is one of the first — if not the first — time it's been used on a complete skeleton,” Libke said. “It was really
exciting to be a part of.”
A 3D-printed replica of the Tokaryk's smooth turtle fossil is now on display at the T.rex Discovery Centre in East End, Sask.