Fossils in Focus: Mosasaur

Remember that scene in Jurassic World? The movie where the giant meat-eating fishy dino jumps out of the pool like a dolphin and eats the shark whole?

Pretty cool, right?

Yeah… that’s probably not what they were like at all.

I love the Jurassic World/Jurassic Park franchise, but they really love to embellish quite a bit when it comes to their portrayal of dinosaurs and reptiles of the past. And the Mosasaur is a prime example of that.

That also leads me to my next fossil!

Mosasaur is actually the name of a broad group of large, and extinct, predatory marine reptiles that lived in the late cretaceous period between 101-66 million years ago. Within that group, are the subfamilies you might be more familiar with such as Mosasaurinae, Halisaurinae, and Tylosaurinae…


You’re not familiar with those?

Ok then… how about an example like Mosasaurus? Yes?

Damn you, Jurassic World!

Fun fact: The name Mosasaur (and incidentally Mosasaurus) is derived from the Latin word Mosa and the Greek word sauros, meaning “lizard of the Meuse River.” It was so named in 1822, referring to the large fossil deposits near the Meuse. The man responsible, William Daniel Conybeare, was quite famous for discovering… nothing as far as I can tell. Really…he didn’t find a thing. He just studied stuff after the digging was done.

Alright, so, Mosasaurus (Mosasaurus hoffmani) is a genus of Mosasaur that lived more in the 82-66 million year range of the cretaceous period. As the largest of the species, this horrifying thing could theoretically reach up to a length of 17.1 meters. The largest confirmed specimen to date is approximately 13 meters. And this is also where Jurassic World gets it wildly wrong in favour of wowing you on the big screen. By comparison, the Mosasaurus from the first movie would be up to 40 meters in length. That’s more than three times the size of the largest fossil construct to date! We won’t even discuss what they’ve done with the poor guy in the sequel.

Fun fact: Mosasaurs were, on average, longer than a T.-rex

Another thing the movie most likely gets wrong is the water acrobatics display and its ability to jump out of the water. While muscular, this beast weighed probably close to 6 tons. The truth is, the tail probably wouldn’t be able to produce enough speed for it to move out of the water like an orca at a marine park.

I still love those movies, though…

Fun fact: The Mosasaurus gave birth to live young, much like modern-day whales and livebearing tropical fish.

Anyway. Back to the fossil!

This Mosasaurus jaw is a fossil I picked up in a shop in Drumheller, Alberta. It consists of a set of teeth embedded in sandstone. The piece is usually called a matrix and is often used to keep a section of fossils together for display or integrity purposes. This one measures 7.5″ x 6.5″ and is in good condition. Each tooth in the matrix measures between 1.5″ and 2” in length. The other thing to note about this piece, in particular, is that it includes several shards and sections of bone; some of them connected to the teeth, while others are sitting loose.

Now, you might recall that in one of my previous posts, I may have mentioned that if you don’t know what you’re doing with fossils, it’s easy to be taken advantage of. Here is an example of how dangerous this can be. Some of the most commonly faked fossils are Mosasaur Jaw sections such as these. The teeth can be replicated using a variety of materials and painted to look old. In addition, the bone sections can often come from common day animals such as goats or cattle. When I bought this piece, I didn’t know any better. However, I got a second opinion, and I ended up lucky. The teeth are genuine, which already makes it worthwhile. The bone is still in question though, and the piece, as a whole, is most likely a reconstruction. The alignment of the teeth alone are almost too perfect and can indicate intentional placement. That’s the downside. So please, remember to do your research! Only buy from reputable dealers and learn what to look for!

Regardless, there’s enough genuine fossil here to make me more than happy, and it looks great on the shelf. On top of that, I have a great conversation piece!

Reminder: I am an amateur collector. I’m still learning as I go, so if you have anything to add or want to point out that I’m wrong about something, I’m very receptive. I just ask that you be polite about it. I’d love to chat more!

And once again, that concludes another session of Fossils in Focus. I hope you learned something fun, new, or exciting. And if you didn’t, I hope you at least clicked on the link so I can tell people that someone actually visited for this post!

Until next time nerds!

Coverage Image Credit: EsthervanHulsen

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