Tuesday, August 27, 2013

Summer's End

So today marks the end of field season for us summer staff! For most of us, school starts next week (!), so it's time to pack up our fossil gear and get back into the swing of doing essays and lab reports. Joe, our curator, will still be outside digging fossils and giving tours until the end of October, so don't worry, there's still lots of time to get a personal tour of the CFDC.

It seems like we've only been here a month, but there's a lot we've accomplished; doing tons of plaster jackets (many more than last year), exploring Pembina Valley Provincial Park in much greater detail than has been done before, and, of course, finding a whole bunch of new fossils, including squid, bony fish, sharks, and lots of mosasaurs. The museum's first ever Shark Week gave us the opportunity to display some of our best fossil shark material that, to my knowledge, has never been put on exhibit before (and next year will be even better!), while Bruce's Birthday, Kidsfest in Winnipeg, and Morden's Corn & Apple were awesome events that put us in touch with tons of people who didn't even know that fossils existed in Manitoba.

While travelling in the Provincial Park was a lot of fun, my favorite part of the year was finding a teensy-tiny, really well-preserved mosasaur backbone, one of the smallest in the entire collection. Digging for fossils can become frustrating after a while, but a sweet find like that vertebra instantly injects new enthusiasm into the hunt. I didn't achieve my goal of locating a pterosaur (flying reptile) skull, but a mosasaur's pretty nice too!

The Fossil Crew (mostly Aaron) has been working on improvements and replacements for various CFDC exhibits. Hopefully, we'll be installing many of these in the coming months and years, so even though we may be gone by then, there'll be a bunch of cool stuff for you to see that we'll have left behind. If that's not incentive to come visit, then I don't know what is! Meanwhile, there's plenty of things to check out already, so come on down. Until next year,

Matt Remple
Field Tech

Friday, August 23, 2013

Corn & Apple

The Corn & Apple Festival is fast approaching! The city's biggest event of the year is this weekend, when Morden is flooded with festival-goers and the temperature attains new heights (this year, at least). If you'd like to enjoy a fossil dig as part of the weekend's activities, there's tours leaving from the booth downtown three times a day today and tomorrow (but not Sunday). I can (almost) promise that there won't be any ticks out in the field! Failing that, we'd be more than happy to see you at the museum or at the booth.

Shark Week culminated with the Beach Blast at Minnewasta Lake this past Saturday, complete with a Dunk Tank and a shark tooth hunt in the sand. During the week, we had Discovery Channel's Shark Week playing the gallery, complemented by a display courtesy of the University of Manitoba, size comparisons of our fossil sharks to Bruce, and a big skeleton from a Cretoxyrhina, one of the biggest sharks to swim in the Cretaceous period. Don't worry (too much) if you missed it, though; we plan to celebrate Shark Week every year from now on! The exclusive exhibits will only get better.

Recent discoveries from the field include a number of ribs and vertebrae (backbones) from a mosasaur that we're currently uncovering; multiple fish teeth and vertebrae from the same site, some of which belong to Xiphactinus, our biggest bony (non-shark) fish at a maximum length of 18 feet; part of a squid pen from a 40-foot-long Tusoteuthis; and a nice tibiotarsus (leg bone) from a diving bird (like a penguin) called Hesperornis, one of the few bird fossils found this year. We've done a lot of plaster jacketing in the last week or so too, which involves covering a section of fossil-containing shale in a protective plaster cast, similar to those used to stabilize broken bones. Once the cast hardens, we bring it back to the museum; with all the recently-made jackets, the lab preparators are going to have a lot of work this winter! Their task of cleaning the surrounding shale matrix off the fossils is a difficult and time-consuming process.

Matt Remple
Field Tech

Monday, August 12, 2013

Shark Week!

Shark Week's coming to the CFDC! For those of you who haven't gotten your fill of sharks from Discovery Channel's Shark Week, we're staging our own six-day event, complete with a new exhibit, shark activities for kids during Dino Day Camp, and special digs for shark fossils. We've been pretty busy setting everything up, and the final display is going to look pretty awesome; there's preserved sharks from the University of Manitoba, a microscope set up with slides of shark skin, and a giant fossilized Cretoxyrhina shark that comprises three huge field jackets.
Cretoxyrhina vertebra with the
jaws of a baby Great White.

Because of the emphasis on sharks, I thought I'd do a little feature on the ones that we find around Morden, kind of like the one I wrote about mosasaurs a few weeks ago. We get four different kinds of shark here, all of which lived during the Late Cretaceous and went extinct millions of years ago. Since sharks are cartilaginous, their skeletons don't fossilize very easily (cartilage is the soft tissue that your nose and ears are made out of); usually, we'll only find their teeth, which are much harder and more durable.

I'm not so sure about this...
Cretoxyrhina is our most awesome shark, topping out at 24 feet (similar to Great Whites) and possessing a dominant spot in Western Interior Seaway ecology. Its size enabled it to confidently challenge and defeat plesiosaurs, small and mid-size mosasaurs, and every other kind of fish that lived at the time, and its teeth are large and smooth, helping it to slice straight through bone and cause catastrophic injury to its prey. Despite its effectiveness in combat, however, it eventually lost the fight for top spot in the food chain to bigger mosasaur genera like Tylosaurus and went extinct about 80 million years ago. As such, we only find Cretoxyrhina in older shale layers where mosasaurs are very uncommon. Fortunately, it tends to fossilize extremely well in those layers relative to other prehistoric sharks, with a number of nicely articulated (meaning that much of the skeleton is still in one piece) specimens having been discovered in North America, including some at the CFDC.

Squalicorax is our most common shark in terms of the number of teeth we find; at about 10 to 16 feet long, it was lower down on the food chain than mosasaurs, plesiosaurs, and the biggest of fish, and as such, it likely engaged in a lot of scavenging activity in addition to the normal predation on smaller marine creatures that people expect from the well-known sharks of today. This versatility combined with a smaller food requirement made it a better survivor than Cretoxyrhina, living until the end of the Cretaceous period when the dinosaurs finally went extinct. For whatever reason, Squalicorax is the only local shark that has serrated teeth, which would have been useful for peeling flesh off of bones.

We also get sharks called Cretolamna and Archaeolamna around Morden, but they're very rare and there isn't much known about our local species. They were likely a little smaller than Squalicorax, but didn't possess the more effective serrated teeth. Worldwide, the Cretolamna genus is known to have survived the mass extinction 65 million years ago, living for about another eight million years in North America and 25 million years around the north-western regions of Africa before going extinct, while Archaeolamna probably died out with the dinosaurs and marine reptiles.

Sharks as a group survived the end of the Cretaceous and, being efficient and sophisticated hunters, are the preeminent marine creatures in many ocean habitats today. This week coming up, we're going to have all our best shark material on display, so be sure to come see it! Everything will be taken down after August 17 to be put away for next year.

Matt Remple
Field Tech