Friday, 28 December 2018

KOURISODON PUNTLEDGENSIS

Kourisodon puntledgensis
Mosasaurs were large, globally distributed marine predators who dominated our Late Cretaceous oceans. Since the unearthing of the first mosasaur in 1766 (Mulder, 2003) we've discovered their fossil remains most everywhere around the globe — New Zealand, Antarctica, Africa, North and South America, Europe and Japan.

We've now found the fossil remains of an elasmosaur and two mosasaurs along the banks of the Puntledge River, says Dan Bowen, Chair of the Vancouver Island Palaeontological Society.

The first set of about 10 mosasaurs vertebrae (Platecarpus) was found by Tim O’Bear and unearthed by a team of VIPS and Museum enthusiasts led by Dr. Rolf Ludvigsen. Dan Bowen and Joe Morin of the VIPS prepped these specimens for the Museum.

In 1993, a new species of mosasaur, Kourisodon puntledgensis, a razor-toothed mosasaur, was found upstream from the elasmosaur site by Joe Zembiliwich on a fossil field trip led by Mike Trask. A replica of this specimen now calls The Canadian Fossil Discovery Centre in Morden home. What is significant about this specimen is that it is a new genus and species. At 4.5 meters, it is a bit smaller than most mosasaurs and similar to Clidastes, but just as mighty. It shared its environment with a variety of Elasmosaurids, turtles, and other mosasaurs, although it seems that no polycotylids were present in its Pacific environment.

Interestingly, this species has been found in this one locality in Canada and across the Pacific in the basal part of the Upper Cretaceous — middle Campanian to Maastrichtian — of the Izumi Group, Izumi Mountains and Awaji Island of southwestern Japan. We see an interesting correlation with the ammonite fauna from these two regions as well. What we do not see is a correlation between our Pacific fauna and those from our neighbouring province to the east. Betsy Nicholls and Dirk Meckert published on the marine reptiles from the Nanaimo Group (Upper Cretaceous) of Vancouver Island in the Canadian Journal of Earth Sciences in 2002. What we see in our faunal mix reinforces the provinciality of the Pacific faunas and their isolation from contemporaneous faunas in the Western Interior Seaway.