Earth Sciences Unit: Neat Stuff - Palaeontology
The Tylosaur - A Voracious Sea Monster
The Earth Sciences Collection includes the 72-million year-old skeleton of a tylosaur. This tylosaur was found near Lake Diefenbaker and is the only specimen of its kind from Saskatchewan. A tylosaur is a type of mosasaur, a large streamlined marine reptile with large jaws for catching fish, swimming mollusks and small reptiles. Tylosaurs were widely distributed; specimens of similar animals have also been found in New Zealand. They probably spread into new habitats by migrating through North America's inland sea and across short stretches of open ocean.
The bones of the RSM's tylosaur are in excellent condition, and its skeleton is mostly complete from the base of the tail forward. When it was alive, it probably measured more than 6 metres from nose to tail, a formidable sea monster. Even more fascinating, a smaller mosasaur skeleton was found behind the ribcage area of the tylosaur, suggesting that the second mosasaur might have been dinner! This conclusion is uncertain, however, because the mosasaur bones do not show obvious signs of being partially dissolved or etched by the tylosaur's stomach acid. The two reptiles might have simply died and come to rest at the same spot. There is much to learn from the RSM's tylosaur fossil, and the skeleton is currently being studied by palaeontologists at the University of Alberta.
 Tylosaur quarry map showing bones as they were found in the field. |
 Tylosaur skull being prepared by RSM Paleo Technician. |
The Calf Creek Collection - An Amazingly Abundant Fossil Site
The Calf Creek Locality was discovered in the 1930s, northwest of Eastend in the eastern part of the Cypress Hills. An incredible number of fossils from the late Eocene (37-36 million years ago) have been found at this location. The RSM's Earth Sciences collection contains more than 4000 items from the Calf Creek Locality, from tiny mouse-sized teeth of small rodents to the enormous bones of rhinoceros-like brontotheres. Additional specimens are housed in eastern museums such as the Royal Ontario Museum in Toronto and the Canadian Museum of Nature in Ottawa. The abundant "microfossils," the bones and teeth of smaller animals, were concentrated by water currents in a "lag deposit" in an ancient stream. The sandy sediments were perfect for burying and preserving the fossils.
Many bones and teeth of mammals have been discovered at the Calf Creek Locality, and RSM and other palaeontologists have identified more than 70 mammal species, mostly from their teeth. Most species of mammal have distinctive-looking teeth, often with a unique pattern of ridges and bumps. It is usually more difficult to identify species of birds, reptiles and other organisms from small fossil fragments, which usually don't have unique features. Because the Calf Creek collection is so large, we feel that we have a reasonably complete picture of which mammals lived in southern Saskatchewan during that time period. All in all, the Calf Creek collection has provided an extremely important piece of the puzzle to Saskatchewan's past, at a time when temperatures were becoming cooler and forests were opening up into parkland habitat.
Reconstruction of the Calf Creek Locality on display in the Earth Sciences Gallery.
For further information contact the Curator of Earth Sciences
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